AudioCircle

Audio/Video Gear and Systems => The Lab => Topic started by: wushuliu on 8 Mar 2010, 09:31 pm

Title: DIY DAC Kits and Easy Mods
Post by: wushuliu on 8 Mar 2010, 09:31 pm
I did some searching through AC to see if there was any info on the recent spate of DAC kits out of China/HK that are very popular on other forums. I didn't find much info at all so I thought I would add some info as well as easy mods to get improved performance.

The most documented are the 24/192 upsampling boards offered by Gigawork and Snow48-6. Both are reliable sellers with speedy (for HK overseas) shipping.



(http://www.audiocircle.com/image.php?id=27584)

This one comes with USB/Coaxial/Toslink input, upsampling board, and a high quality R-core transformer. Best bargain. These DACs use cs4398 chip and come stock with 5532 opamps. The opamps are not soldered and are therefore swappable.

http://cgi.ebay.com/Gigawork-24-192-Up-sampling-DAC-DA-CONVERTER-w-USB-kit_W0QQitemZ120540707231QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c10c9399f (http://cgi.ebay.com/Gigawork-24-192-Up-sampling-DAC-DA-CONVERTER-w-USB-kit_W0QQitemZ120540707231QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c10c9399f)


(http://www.audiocircle.com/image.php?id=27585)

This one is cheaper with no USB, no upsampling, and no transformer.

http://cgi.ebay.com/NEW-BIG-24bit-192Hz-HI-FI-DAC-DIY-KIT-ASSEMBLED-MODULE_W0QQitemZ140389033636QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item20afd6a6a4 (http://cgi.ebay.com/NEW-BIG-24bit-192Hz-HI-FI-DAC-DIY-KIT-ASSEMBLED-MODULE_W0QQitemZ140389033636QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item20afd6a6a4)


(http://www.audiocircle.com/image.php?id=27586)

This guy is the cheapest but requires the most modding. I would recommend sticking with one of the above.

http://cgi.ebay.com/24bit-192KHz-DAC-DIY-KIT-FULL-ASSEMBLED-KIT_W0QQitemZ230445112086QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item35a7995b16 (http://cgi.ebay.com/24bit-192KHz-DAC-DIY-KIT-FULL-ASSEMBLED-KIT_W0QQitemZ230445112086QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item35a7995b16)


Apparently you can request a completely built version of the first kit with a nice aluminum enclosure for $250 shipped. There are pics on the Aussie forum linked below.


The general consensus seems to be that stock/opamps mod they compete w/ retail anywhere from $600 to $2k range. Once you add transformer outputs, however, all bets are off and you open the vortex that is audio nirvana. Not bad for $150 inc. power supply.

There are quite a few threads out there on these:

This aussie thread is a good one w/ pics and info

http://www.stereo.net.au/forums/showthread.php/16138-My-new-dac (http://www.stereo.net.au/forums/showthread.php/16138-My-new-dac)

For masochists, the Diyaudio thread is a monster at 250 pages:

http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac.html (http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac.html)



I’ll come back to add more info once I’m done w/ the B1 tutorial.
Title: Re: DIY DAC Kits and Easy Mods
Post by: Mariusz on 8 Mar 2010, 09:37 pm
THX Wushuliu.  :thumb:
We need more of these IMHO.


Cheers
Mariusz :P
Title: Re: DIY DAC Kits and Easy Mods
Post by: avionic on 9 Mar 2010, 02:08 am
Wushuliu, I can't read any more of your threads. Every time I do I end up spending more $$. Seriously though I will be following this one with great interest.
Title: Re: DIY DAC Kits and Easy Mods
Post by: HT cOz on 15 Mar 2010, 01:12 pm
Very cool thread  :hyper:  I can see a future B1-DAC combo.  These threads have me thinking I really need to get in on the action.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 15 Mar 2010, 07:57 pm
Yeah, I'm *real* happy with mine. I am waiting for the nice new transformer that now comes with the kit (I have the older one that's not so great quality), then I will start the tutorial. I also have very inexpensive Edcor transformers coming for the output so I am really, really excited.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 15 Mar 2010, 08:06 pm
Based on component choice and PCB layout, I would avoid the first two. Cirrus Logic, the company that makes the CS8416 S/PDIF receiver chip, gives very specific recommendations regarding components and layout to maximize performance and minimize jitter. Locating the CS8416 on a daughter board and using through-hole passive components is contrary to Cirrus’ advice.

The general consensus seems to be that stock/opamps mod they compete w/ retail anywhere from $600 to $2k range. Once you add transformer outputs, however, all bets are off and you open the vortex that is audio nirvana.

Are you kidding? Not with the crap power supplies and voltage regulators. A poorly implemented Sigma-Delta DAC is more like audio hell.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 15 Mar 2010, 08:10 pm
Based on component choice and PCB layout, I would avoid the first two. Cirrus Logic, the company that makes the CS8416 S/PDIF receiver chip, gives very specific recommendations regarding components and layout to maximize performance and minimize jitter. Locating the CS8416 on a daughter board and using through-hole passive components is contrary to Cirrus’ advice.

Are you kidding? Not with the crap power supplies and voltage regulators. A poorly implemented Sigma-Delta DAC is more like audio hell.

Yeah, well it must have froze over cause it sounds pretty good down here!
Title: Re: DIY DAC Kits and Easy Mods
Post by: Atlplasma on 15 Mar 2010, 08:27 pm
I purchased the big Gigaworks DAC in 2009. I'm using it with my Mac Mini music server over USB. So far it's been very reliable. I've also purchased the parts for the DIY output mods but haven't gotten around to putting them in.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Mar 2010, 09:54 pm
Tutorial


Ok, let me start off by saying that there are quite a few mods out there for these kits. I am only covering what I consider to be the easiest as I am lazy and believe in getting the most with the least amount of work.

Also, it goes without saying to please be careful and I am not responsible for anything that may go wrong. Proceed at own risk, etc.

These mods pertain to the first two kits; Power supply pertains to the R-core provided for the first kit (and the second I'm sure if you ask the seller)

I will focus on 3 choices: Stock, opamp/cap mods, and output transformer mods.

1. Stock

There is nothing that needs to be modified or added to the stock kits. You can swap opamps at your leisure. All you need do is attach the power supply and then plug in the inputs and rca's as you see fit. Be sure to consult documentation re: dac switches and jumpers for the different inputs. The seller should have provided a cd w/ the necessary info. Now you can go straight to the Power Supply Transformer section below.

2. Opamp/cap mods

The Goal : get rid of some bypass/filter caps next to the dac, jumper them, replace output caps

Startin' w/ these guys

(http://www.audiocircle.com/image.php?id=28115)

(http://www.audiocircle.com/image.php?id=28116)

Now if your board has different color capacitors or slightly different values, don't matter. There'll
be 4 of them and they need to go.

Important: This solder on this board is finicky. I do not recommend applying the soldering iron to the bottom of the board. In my experience the pads tend to melt or just disappear into the board. So I recommend working only with the top side.

What I did was rock each cap back and forth until they broke off. (Given the finickiness of the board I wouldn't worry about 'saving' them so you can put them back in. It'll be more trouble than it's worth unless you're a pro with an adjustable temp workstation, etc.)

Then I bridged each side of each cap positive and negative side with some solder. You can also use a piece of wire, etc.

(http://www.audiocircle.com/image.php?id=28117)


Next, Output caps

This may be tricky w/ the rca inputs in the way. I recommend pulling those out of there as they're very flimsy, and using some decent rca inputs and wire. Chances are to accomodate an enclosure you'll have to anyways...

Output caps can be replaced with the cap of your choice. The holes require small leads, so I clipped off thin leads from spare resistors and soldered them to my cap leads.

(http://www.audiocircle.com/image.php?id=28118)

In the rear you'll see I also replaced the caps before the second opamp. Whether you want to try this is up to you. Since the layout of these boards seem to change every six months, some boards may not even have them.

That's it!

I found this mod to be far superior to the stock sound. Clears things up a lot.

You can also try some of Dave's mods below: getting rid of those 4 bypass caps, getting rid of the second opamp and jumping the bypass caps that sit before it. Jump the pins to keep mute relay (see his post), and losing the output caps altogether.

This is a good option as it doesn't involve replacing any of the caps, just pulling stuff out and jumping with wire, etc. And losing the second opamp is a plus


to be cont'd














Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Mar 2010, 09:55 pm
Line Output Transformer Mod

Next up is the output transformer mod. This is also fairly easy.

1) You bypass opamps altogether.

2) Minimal contact w/ the board, reducing risk of screwing something up while (de)soldering.

2) Since you don't need the opamps you won't need to use the ~ 12v -0- 12v part of the power
supply, only the ~9v-0 part (see Transformer/PS section below). So basically you can run out to Radio Shack or digikey or wherever and use a cheap 9v transformer, buy the kit w/o transformer from ebay and save money to use towards the *line output* transformers.

Next, Getting signal from Bypass caps

This is what you're going for. Here's a great basic pic from diyaudio:


(http://www.audiocircle.com/image.php?id=28135)

and a diagram (applies to both Left and Right):



(http://www.audiocircle.com/image.php?id=28137)


You will need resistors and caps for the filters. You can start with ~500ohms for R1 and 1nf
for C1 and then adjust up or down to taste. I also recommend PRP or Takman resistors. They are cheap
and I think preferable to the usual dale, etc. in this application. Or better yet, compare for yourself.

Let's get started.


You want to solder in the 4 signal wires. They will go the transformers and from the transformers to your RCAs

In the Opamp mod section I showed the 4 Bypass caps by the dac chip that were tossed. Same
applies here. However, instead of jumping them we will be drawing the audio signal.

From Left to Right the signal goes: R-/R+/L+/L-

You will only need to deal with the positive (unstriped) side of each one. Like so:


(http://www.audiocircle.com/image.php?id=28133)

I still recommend rocking the caps to break them off, thus avoiding full desoldering on the bottom side of the board. Then use tweezers to pull out the leads. Much easier and reduces iron time on the pads.

Also, the dac chip is removeable. So if you feel a little cramped during this part, gently pull up the dac chip from its sockets...

When you're done, should look like this:


(http://www.audiocircle.com/image.php?id=28134)

That's it for the board. Phew. Now you can be butterfingers all you want with the output transformers!


Which Output Transformers?

A wide bandwidth (20hz - 20khz or higher) 500/600:500/600 is a good start. The average price for a pair is ~$100 - 150. American-made Edcors, however are a budget alternative. Not a huge amount of feedback on their quality, but it's a reputable company.

Most Popular

UTC/TRW A-20

http://cgi.ebay.com/Pair-UTC-A-20-Input-Transformer-500-500-Ohm_W0QQitemZ310206172473QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item4839ba8d39

(http://www.audiocircle.com/image.php?id=28131)

Cinemag - ~$56 ea.

CMOB - 2H

http://www.cinemag.biz/output/output.html (http://www.cinemag.biz/output/output.html)

Altec 15356/A (on and off on ebay)


(http://www.audiocircle.com/image.php?id=28132)

EDCOR XSM600 - ~$13 ea.

http://www.edcorusa.com/Products/ShowProduct.aspx?ID=327 (http://www.edcorusa.com/Products/ShowProduct.aspx?ID=327)

These are just a few of the many to choose from. I also focused on options easily available to those
in the U.S.. Internationally there are Sowters, LLundahls, Monacors,etc. that are easier to find. You get the idea.

Now each transformer brand is different as far as their primaries (input) and secondaries (output to RCA). We want to follow the 5 or 600: 5 or 600 diagrams. In the UTC pic above for instance you can see the writing on the side:

Pins 1 and 6 = primary, signal from the board
      7 and 12 = secondary, signals to RCA
      3 and 4, 9 & 10 = Center Tap, you jump/connect these two w/ wire

So consult the transformer you have and if you have any questions just ask.

Now add the resistors and cap filter to the signal wires.

Just as in the diagram above.


(http://www.audiocircle.com/image.php?id=28138)


then attach, solder, etc to appropriate pins on your transformer.



(http://www.audiocircle.com/image.php?id=28140)


You can see the white output wires that are going to the RCAs. I did not take a close pic of the
1K, 1nf R-C filter but you can kind of see here. Just follow the diagram above.


(http://www.audiocircle.com/image.php?id=28141)

(http://www.audiocircle.com/image.php?id=28152)

There ya be. Not too tough was it?

















Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Mar 2010, 09:55 pm
Power Supply Transformer

The first kit comes with a R-core R26-34 transformer for the power supply. It is also available separately on ebay. It's a mad jumble of wires but you'll only be using some, not all.

Note: The wiring in this post pertains to US/115v only!

Stock/Opamp mod wiring

On the board you will see at the back two inputs for 7-10v and three inputs for (12 to) 15v-0-15v

(http://www.audiocircle.com/image.php?id=28153)


For the 7-10v you will use the two brown wires

For the 15v-0-15v you will use a grey at one end, blue at the other, and BOTH in the center

Here is a great diagram  provided at diyaudio:

(http://www.audiocircle.com/image.php?id=28154)

The remaining wires on that side should clipped/taped up and tucked away


For Output Transformer/No Opamps Mod

Since you will be bypassing the opamps completely, there's no need to worry about the 15v-0-15v
side. Nip/Tuck those away and just wire up the 7-10v with the two brown wires!


Primary/Mains

OK, please look at the diagram above.

Wire the Red and Green together for your LINE voltage

Wire the Orange and Yellow together for Neutral.

(http://www.audiocircle.com/image.php?id=28155)



Remember this applies to 115v/USA only


You will want to add the Power switch to the Line of course.

The rest of the setup is up to you.

Here endeth the Lesson. Be Careful and Have Fun. 8)





Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Mar 2010, 09:56 pm
I purchased the big Gigaworks DAC in 2009. I'm using it with my Mac Mini music server over USB. So far it's been very reliable. I've also purchased the parts for the DIY output mods but haven't gotten around to putting them in.

I thought I read you bought the Altec 15356 transformers. I just got some on the 'bay...
Title: Re: DIY DAC Kits and Easy Mods
Post by: Atlplasma on 18 Mar 2010, 10:47 pm
I thought I read you bought the Altec 15356 transformers. I just got some on the 'bay...

That's correct. I have everything I need for the mod but have been waiting for some downtime to take it on. I'd be curious to see how yours turns out.

Steve
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 21 Mar 2010, 07:07 am
IT'S ALIVE!

(http://www.audiocircle.com/image.php?id=28048)

(http://www.audiocircle.com/image.php?id=28119)





Gonna give it some time to settle and I have some higher quality parts coming to replace some of what's being used now.

First impression w/ these Altec transformers (and R-core transformer)  is that the sound is indeed more natural and very three dimensional compared to mod I had before and of course far better than stock.

I'll add pics and more info later on this week.

Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 22 Mar 2010, 07:17 pm
I'm going to grab one of these and do some of the diy mods as well.  I might try to add the decware tube output too.

Is there an organized tutorial for the mods somewhere or are you referring to the lampizator site?  I I was worried I would have trouble following that website if all the PCB IDs are different on the "better boards," rather than the third one above, which it appears was the board used on the lampizator site.  I am a proficient solderer, but these types of mods are totally new to me, so I don't want to bite off more than I can chew:)
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 22 Mar 2010, 08:48 pm
I'm going to grab one of these and do some of the diy mods as well.  I might try to add the decware tube output too.

Is there an organized tutorial for the mods somewhere or are you referring to the lampizator site?  I I was worried I would have trouble following that website if all the PCB IDs are different on the "better boards," rather than the third one above, which it appears was the board used on the lampizator site.  I am a proficient solderer, but these types of mods are totally new to me, so I don't want to bite off more than I can chew:)

This *is* (or will be) the only organized tutorial on this kit (as far as basic and transformer output mods). Otherwise you can slog through the 225 pages on diyaudio, which is where I draw my info. There are several kinds of mods for these boards. The Lampizator takes a different approach altogether and I won't be covering that (just looks too messy to me). My focus is on getting the most benefit w/ the least amount of work/mess. I'll have the pics and info up very, very soon.
Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 22 Mar 2010, 09:10 pm
That's awesome.  Its noble of you to finally pull a tutorial together given how in depth and fragmented the discussion of this DAC has been on the numerous boards.  I look forward to hearing about your experience.
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 22 Mar 2010, 09:52 pm
I did some searching through AC to see if there was any info on the recent spate of DAC kits out of China/HK that are very popular on other forums. I didn't find much info at all so I thought I would add some info as well as easy mods to get improved performance.

The most documented are the 24/192 upsampling boards offered by Gigawork and Snow48-6. Both are reliable sellers with speedy (for HK overseas) shipping.



(http://www.audiocircle.com/image.php?id=27584)

This one comes with USB/Coaxial/Toslink input, upsampling board, and a high quality R-core transformer. Best bargain. These DACs use cs4398 chip and come stock with 5532 opamps. The opamps are not soldered and are therefore swappable.

http://cgi.ebay.com/Gigawork-24-192-Up-sampling-DAC-DA-CONVERTER-w-USB-kit_W0QQitemZ120540707231QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c10c9399f (http://cgi.ebay.com/Gigawork-24-192-Up-sampling-DAC-DA-CONVERTER-w-USB-kit_W0QQitemZ120540707231QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c10c9399f)


(http://www.audiocircle.com/image.php?id=27585)

This one is cheaper with no USB, no upsampling, and no transformer.

http://cgi.ebay.com/NEW-BIG-24bit-192Hz-HI-FI-DAC-DIY-KIT-ASSEMBLED-MODULE_W0QQitemZ140389033636QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item20afd6a6a4 (http://cgi.ebay.com/NEW-BIG-24bit-192Hz-HI-FI-DAC-DIY-KIT-ASSEMBLED-MODULE_W0QQitemZ140389033636QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item20afd6a6a4)


(http://www.audiocircle.com/image.php?id=27586)

This guy is the cheapest but requires the most modding. I would recommend sticking with one of the above.

http://cgi.ebay.com/24bit-192KHz-DAC-DIY-KIT-FULL-ASSEMBLED-KIT_W0QQitemZ230445112086QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item35a7995b16 (http://cgi.ebay.com/24bit-192KHz-DAC-DIY-KIT-FULL-ASSEMBLED-KIT_W0QQitemZ230445112086QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item35a7995b16)


Apparently you can request a completely built version of the first kit with a nice aluminum enclosure for $250 shipped. There are pics on the Aussie forum linked below.


The general consensus seems to be that stock/opamps mod they compete w/ retail anywhere from $600 to $2k range. Once you add transformer outputs, however, all bets are off and you open the vortex that is audio nirvana. Not bad for $150 inc. power supply.

There are quite a few threads out there on these:

This aussie thread is a good one w/ pics and info

http://www.stereo.net.au/forums/showthread.php/16138-My-new-dac (http://www.stereo.net.au/forums/showthread.php/16138-My-new-dac)

For masochists, the Diyaudio thread is a monster at 250 pages:

http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac.html (http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac.html)



I’ll come back to add more info once I’m done w/ the B1 tutorial.
I bought a couple of these and I have done the mods on the diyAudio forum + a couple:

Replaced the Philips diodes with 1A 100V schottkys

Added additional bypassing on the caps in the power supplies

Removed all of the coupling capacitors and replaced them with jumpers

Removed the buffer op amp and added 1/3 & 5-7 jumpers to allow the mute relay to still be used

Replaced the latching diode at the relay with a UF4007 (I have a million of them for guitar amps)

Replaced the output opamp with Gigaworks dual OPA627 daughter board

Removed the USB input assembly in totality

Mortite damped the upsampling daughter board

Lead damped the Crystal DAC and input receiver

I will be using the coax out only so I ordered Canare 75 ohm RCA's and plugs for the case

I will replace the output RCAs with Gigaworks silver RCAs

Both of the last mods will happen when I receive the cases that I ordered for the DACS

I have sourced cases with extruded side panels (w/card slots), plate top, bottom and end panels in natural aluminum.  They are sized to just let the board slide in and are nominally 12" x 5.35" x 3.5" to allow the TX, IEC inlet and all other goodies room to breathe.  I did not order the panels machined to allow for the end user to use any type of configuration they wish.  If anyone is interested in one of these cases, drop me a PM and we can talk. 

The DAC sounds quite good with these mods.  I'm using a Blue Jeans 1M RCA digital interconnect right now.  It is very open with great dynamics and very good detail and lacks any harshness.  It is musical and even though it is no match for my old Cary 306 it is more fun to listen to for extended periods.  Last word: my wife likes it the best.

I'll be rolling some digital cables of my own and several other manufacturers, including the Nady.

My .02

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 22 Mar 2010, 09:58 pm
Thanks Dave. You got busy on that thing. Happen to have any pics?
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 22 Mar 2010, 10:01 pm
Thanks Dave. You got busy on that thing. Happen to have any pics?
I went ahead and took some new pictures.  I forgot to shoot the new diodes, but, hey:  they are just diodes :)



(http://www.audiocircle.com/image.php?id=28106)

This is an overview of the mule




(http://www.audiocircle.com/image.php?id=28107)

This captures most of the mods in one picture




(http://www.audiocircle.com/image.php?id=28108)

USB input area stripped.  I removed the 3-pin regulator in the bottom of the board




(http://www.audiocircle.com/image.php?id=28109)

The replacement RCAs - Canare and Gigawork



I auditioned opamps:
   
    AD826 - forward and hard, almost brittle sounding
    OPA2134 - smooth but not very articulate
    LM4562 - woofy and vague sounding, hard to define some instruments especially in the mid
          to upper bass
    Twin OPA627 (Gigawork) - as always very good with nice bass and smooth yet detailed, very
          dynamic

There you have it so far.  The journey will continue............................... ......

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Mar 2010, 09:14 am
thanks dave!
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 23 Mar 2010, 01:24 pm
thanks dave!
Absolutely!  Any time... I play well with others (mostly see: http://www.audiocircle.com/index.php?topic=79128.new;topicseen#new ) and I share my toys.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: roscoeiii on 23 Mar 2010, 05:51 pm
Mighty tempting stuff in this thread. Could anyone comment on how any of these DACs sound, both before/after the various mods, as well as in comparison to some other DACs to which you may have been able to compare them?
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Mar 2010, 07:50 pm
Mighty tempting stuff in this thread. Could anyone comment on how any of these DACs sound, both before/after the various mods, as well as in comparison to some other DACs to which you may have been able to compare them?

I don't have much experience with other dac's aside from my ht receiver and Oppo 980H, so I am curious to hear how it compares to others as well. I will say that so far the output transformer mod is stellar, with resolution that reminds me of good vinyl.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 23 Mar 2010, 08:37 pm
GIGO. No matter how you upgrade and tweak the opamps and power supply capacitors, the sound you get will be limited by the quality of the output of the DAC chip and the output of the DAC chip will be limited by the quality of the digital output of the S/PDIF receiver chip. In the Gigaworks design, both the receiver and the DAC are hobbled by the use of daughter boards and through-hole components. However, when it comes to modding, the daughter boards are a blessing.

I suggest replacing both the DAC and receiver daughter boards with ones that are augmented with ultra low noise voltage regulators, ferrite beads, C0G and X7R surface mount capacitors, and surface mount resistors. Of course, observing good PCB layout practices to minimize the digital nasties.  Only then can you realize the full potential of the Gigaworks board.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Mar 2010, 08:45 pm
GIGO. No matter how you upgrade and tweak the opamps and power supply capacitors, the sound you get will be limited by the quality of the output of the DAC chip and the output of the DAC chip will be limited by the quality of the digital output of the S/PDIF receiver chip. In the Gigaworks design, both the receiver and the DAC are hobbled by the use of daughter boards and through-hole components. However, when it comes to modding, the daughter boards are a blessing.

I suggest replacing both the DAC and receiver daughter boards with ones that are augmented with ultra low noise voltage regulators, ferrite beads, C0G and X7R surface mount capacitors, and surface mount resistors. Of course, observing good PCB layout practices to minimize the digital nasties.  Only then can you realize the full potential of the Gigaworks board.

Have you made these mods w/ the Gigaworks board? Do you have pics? Can you do a step-by-step tutorial on implementing these mods? Do you have any soldering tips to prevent damaging the sensitive board since quite a few components will be handled?

Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 23 Mar 2010, 09:09 pm
Have you made these mods w/ the Gigaworks board? Do you have pics? Can you do a step-by-step tutorial on implementing these mods? Do you have any soldering tips to prevent damaging the sensitive board since quite a few components will be handled?

No, I don't have a Gigaworks board, nor do I want one. I have enough DACs and I dislike delta-sigma types. I've done digital mods on a similar scale and the results are worth the effort. I posted one such mod in this circle. See: http://www.audiocircle.com/index.php?topic=54998.0
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Mar 2010, 09:16 pm
No, I don't have a Gigaworks board, nor do I want one. I have enough DACs and I dislike delta-sigma types. I've done digital mods on a similar scale and the results are worth the effort. I posted one such mod in this circle. See: http://www.audiocircle.com/index.php?topic=54998.0

Then it does not appear there's much more to be shared on the subject of this thread which is Easy. Kit. Mods.

That said, I highly recommend diyaudio's dac section where many original dac concepts are being explored.

Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Mar 2010, 11:26 pm
Tutorial is under way on Page 1...
Title: Re: DIY DAC Kits and Easy Mods
Post by: Mariusz on 24 Mar 2010, 12:01 am
Cool. :drool: :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 24 Mar 2010, 12:43 am
Then it does not appear there's much more to be shared on the subject of this thread which is Easy. Kit. Mods.

I thought my suggestion was apropos. The CS8412 mod I linked to was my very first scratch designed PCB and the first time I worked with surface mount components. I thought it was very easy. Also, the Audio Note DAC I modded was built from a kit. It was an Easy Mod for a DIY DAC Kit. My suggestions for the Gigaworks DAC would be even easier because they don’t involve any digital circuits, just voltage regulators, ferrites, capacitors, and resistors.

Step by step:
1: Study pinouts of the Gigaworks daughter boards.
2: Study datasheets of the chips involved.
3: Choose components.
4: Design circuits.
5: Layout PCBs.
6: Order PCBs and components.
7: Receive PCBs and components.
8: Solder components on PCBs.
9: Install PCBs.
10: Enjoy.

Below is another view of the CS8412 mod. Left is the CS8412 it replaced. Center is the finished mod. Right is the view from below showing the CS8415A with bypass caps soldered directly to the chip leads. That eliminates ALL trace impedance and reduces lead impedance; both of which reduce noise and ground bounce. For the Gigaworks I would put the CS8416, PLL filter, and bypassing surface mounts on one side of the daughter board and the voltage regulators on the other. Neat, simple, and easy.

(http://internet.cybermesa.com/~jmlpartners/images/dir6a-12.jpg)
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 24 Mar 2010, 01:14 am
I thought my suggestion was apropos. The CS8412 mod I linked to was my very first scratch designed PCB and the first time I worked with surface mount components. I thought it was very easy. Also, the Audio Note DAC I modded was built from a kit. It was an Easy Mod for a DIY DAC Kit. My suggestions for the Gigaworks DAC would be even easier because they don’t involve any digital circuits, just voltage regulators, ferrites, capacitors, and resistors.

Step by step:
1: Study pinouts of the Gigaworks daughter boards.
2: Study datasheets of the chips involved.
3: Choose components.
4: Design circuits.
5: Layout PCBs.
6: Order PCBs and components.
7: Receive PCBs and components.
8: Solder components on PCBs.
9: Install PCBs.
10: Enjoy.

Below is another view of the CS8412 mod. Left is the CS8412 it replaced. Center is the finished mod. Right is the view from below showing the CS8415A with bypass caps soldered directly to the chip leads. That eliminates ALL trace inductance and reduces lead inductance; both of which reduce noise and ground bounce. For the Gigaworks I would put the CS8416, PLL filter, and bypassing surface mounts on one side of the daughter board and the voltage regulators on the other. Neat, simple, and easy.

(http://internet.cybermesa.com/~jmlpartners/images/dir6a-12.jpg)

Looks intriguing but there is no way that what you have outlined is recommended for someone with little or no experience with soldering diy circuits or studying schematics. You are basically saying that one would need to design a tiny pcb from scratch (literally!) with a bunch of smd components. There is no way someone without solid soldering experience with smd's to begin w/ would want to tackle any of that.

This is not a criticism of your design, of course. I'll keep my eye on the thread you linked. It just seems that you're taking for granted the abilities of those for whom this thread is primarily oriented. I still think diyaudio would be a good home for your project. Or better yet. Do an actual step-by-step. Saying 'Study pinouts' is not as helpful as it may seem and again assumes a certain amount of knowledge. Since it's an original design by you you'd want to break it down thoroughly, piece by piece anyway, yes? :scratch:

Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 24 Mar 2010, 01:48 am
You are basically saying that one would need to design a tiny pcb from scratch (literally!) with a bunch of smd components. There is no way someone without solid soldering experience with smd's to begin w/ would want to tackle any of that.

Maybe you missed it. I said the CS8412 project was my very first PCB and my first try at soldering SMD. Hand soldering SMD looks intimidating until you get the courage to try it. It's really very easy. In fact, and most assemblers will agree, it's easier and faster than through-hole! Yes, it takes a little practice and a good soldering iron, but those requirements are no different then when first soldering through-hole components.

Quote
It just seems that you're taking for granted the abilities of those for whom this thread is primarily oriented.

I take nothing for granted except that anyone interested in getting the most from a DAC will do what I did: Read, Think, Study, and Learn. Then use that knowledge to evaluate what others have done and try to improve upon it. BTW, I don’t have any formal education or training beyond high school. If I can do it, anybody can.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 24 Mar 2010, 03:03 am
Maybe you missed it. I said the CS8412 project was my very first PCB and my first try at soldering SMD. Hand soldering SMD looks intimidating until you get the courage to try it. It's really very easy. In fact, and most assemblers will agree, it's easier and faster than through-hole! Yes, it takes a little practice and a good soldering iron, but those requirements are no different then when first soldering through-hole components.

I take nothing for granted except that anyone interested in getting the most from a DAC will do what I did: Read, Think, Study, and Learn. Then use that knowledge to evaluate what others have done and try to improve upon it. BTW, I don’t have any formal education or training beyond high school. If I can do it, anybody can.

Then once again I recommend doing a step-by-step build of your mod with links and pics so we can all benefit.
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 24 Mar 2010, 03:37 am
Mighty tempting stuff in this thread. Could anyone comment on how any of these DACs sound, both before/after the various mods, as well as in comparison to some other DACs to which you may have been able to compare them?
The Gigawork is OK straight out of the box.  It doesn't do anything badly and sounds pretty good for $150.00 (including shipping).  It just sounded kind of hazy due to the 5532 opamps.  They lack resolution and punch.  The first thing I did was to roll in some different opamps without a lot of success.  Sounded better, but not great.  I was using BB OPA2134 opamps.  Next I replaced the Philips diodes with IR 1A 100V schottkys and that helped smooth things out a bit.  Next, I pulled the second buffer opamp and all of the coupling caps and replaced them with appropriate jumpers.   This really opened things up and the soundstage got BWD - big, wide and deep.  I then tried all of the opamps that I mentioned in my earlier post with the results noted.  The double OPA627 board from Gigawork is a steal at $29.95 for a pair with $5.00 shipping.  Single OPA627 opamps are ~ $15.00 each from Digikey.  Gigawork gives you 4 mounted on nicely done adapter boards.  Best thing is that they sound great!  The last mod that I did was to remove the Toslink and USB components from the board.  I will not be using them and it is my observation that unused components, particularly digital parts and pieces, can pollute the groundplane and supply rails with RF and extraneous noise as well as draw power from the system.  This last mod was suprising to me in it's effectiveness in that the jumper positions on the board for USB, coax and Toslink operation "should" have disabled power to the parts I removed when I had the jumpers in the coax setting.  Perhaps I am mistaken in what I hear (and well could be due to the fact that I can't go back and reinstall them to check), but everything just sounds better.  There is more "there" there now.  Everything sounds more open and transparent.  Maybe it wasn't ALL powered down. 

Oh, yeah, I am using a Cambridge Azur 640Cv2 as a transport through a Blue Jeans 1 meter digital cable right now.

Anyway, that is my experience so far.  I have noted the comparison to my Cary 306-200.  Frankly, I like what I am hearing right now.  My system is far from being complete: I still have my GR Research Super V's to bring online, but my little Jordan JX92S single driver speakers are making sweet music as I type this.

HTH.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 24 Mar 2010, 04:36 am
Thanks to everyone's helpful photos and explanations, I think I am ready to take the leap into DIY and grab one of these.  I am really tempted to use the Zkit4 tube output stage from Decware (http://www.decware.com/newsite/zkit4.htm) with the Zkit5.1 power supply (http://www.decware.com/newsite/zkit5.htm).  I am assuming I would pull the R-, R+, L-, L+ from the same place I would pull it if I were using line output transformers?

I don't know if anyone has used these Decware kits before, but do you think there is anything I should be concerned about, or are there other tube output stages I should consider that are in roughly the same range?

If all goes well, I'd like to pair this with a Pass B-1 set-up with a HT bypass switch (not to get ahead of myself).

Thanks in advance.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 24 Mar 2010, 06:07 am
Tutorial all done.

Just let your Soul Glo.

w
Title: Re: DIY DAC Kits and Easy Mods
Post by: jeffjazz on 24 Mar 2010, 06:58 am
Another Tube output  More $$$ but better caps and a separate power supply. http://www.diyhifisupply.com/node/399 (http://www.diyhifisupply.com/node/399)
 There is someone on this site that has used it to good effect.  I am looking to jump on the gigaworks Dac bandwagon, but not sure it would be up to my CD player (Esound) which sounds excellent. 
Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 24 Mar 2010, 02:04 pm
Thanks for the link.  I think I actually saw the post you are referring to.  I was hoping to spend less than that, but maybe it is a better option.  I suppose I could always upgrade the caps onthe decware down the road.  Also, isn't the zkit5 a separate power supply for the stage?  I am pretty new to all this, so I could be missing something.
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 24 Mar 2010, 03:07 pm
Tutorial all done.

Just let your Soul Glo.

w
Thanks for putting all of this together in one place for all to see. 

It is great to tweak on these things (or anything, for that matter) and listen to them come alive.

I will be getting another to do the transformer mod on.  My friend, Sheldon Stokes, has told me that he really likes the Sowter transformers so I think I will start with them and order a couple of other types to keep the learning curve going on these.  They really are over achievers when modded a bit.

Edit: for the TX types:  I just got an email from Sheldon and he told me that for this application he would look to Lundahl or UTC.  He knows transformers, so that is the way I'll go.

Once again: GOOD JOB!   :thumb:

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: Turnandcough on 24 Mar 2010, 04:43 pm
Removed the USB input assembly in totality

Does removing this and the optical input reap any audible benefits or only theoretical? The reason I ask is that the first one of these that I modded(output trafos) was the basic non-USB/upsampling version. For some reason I had also removed the optical input. I'm currently using a "fully loaded" upsampling version board with optical and USB inputs still attached. Maybe my memory is playing tricks on me but it seems that the old board sounded better. Before I start butchering this one I would just like to make sure that I won't be doing it for nothing.
BTW - I'd really like to perform some of those other mods you did but for that I'd need to have the procedure spelled out for me. :wink:
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 24 Mar 2010, 04:57 pm
Does removing this and the optical input reap any audible benefits or only theoretical? The reason I ask is that the first one of these that I modded(output trafos) was the basic non-USB/upsampling version. For some reason I had also removed the optical input. I'm currently using a "fully loaded" upsampling version board with optical and USB inputs still attached. Maybe my memory is playing tricks on me but it seems that the old board sounded better. Before I start butchering this one I would just like to make sure that I won't be doing it for nothing.
BTW - I'd really like to perform some of those other mods you did but for that I'd need to have the procedure spelled out for me. :wink:
You've gotta be a doctor with that moniker  :icon_lol:

Like I said in my post, anything that is not functional in gear that I modify I remove because of the parasitics... either actual or theoretical.  Another reason is that I just hate making square holes in sheet metal when I don't have the punch die.  That is a PITA!

I really do "think" that it sounds better with all of the unused hardware removed.  It is really open, smooth with delicate detail now.  Could be a function of break in, but I doubt it.  I put over a hundred hours on it with a Purist Audio break in disc before I started any of the mods.  Diodes are noisy and I've read that the diode in Toslinks are very much so.  If you aren't going to use it I'd say yank the sucker out!

I will do a detailed modification document with pictures when I take it all apart to put into the case.  I have a stock one here to shoot before and after photos of to help it along.

Hang in there.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: Turnandcough on 24 Mar 2010, 09:49 pm
You've gotta be a doctor with that moniker  :icon_lol:

If you aren't going to use it I'd say yank the sucker out!

I will do a detailed modification document with pictures when I take it all apart to put into the case.  I have a stock one here to shoot before and after photos of to help it along.


I wish I was a doctor then I could cure myself of this disease that makes me want to obsessively change parts on these cheap Chinese DACs.

Let the yanking begin.

Looking forward to your step by step.
Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 26 Mar 2010, 06:21 pm
I ordered the gigawork board without the transformer last night, as I am not going to use the op-amps.  I know I can just use a cheap 9v wallwart to power the digital side, but I wanted to see if it was worth it to look into a better power source?  If so, is there some place I should look?  I would be game for building it myself if it would not be too hard and actually worth my time.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 26 Mar 2010, 07:02 pm
I ordered the gigawork board without the transformer last night, as I am not going to use the op-amps.  I know I can just use a cheap 9v wallwart to power the digital side, but I wanted to see if it was worth it to look into a better power source?  If so, is there some place I should look?  I would be game for building it myself if it would not be too hard and actually worth my time.

Time and money spent on a power source won't be of much benefit unless you also replace the crappy voltage regulators.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 26 Mar 2010, 07:13 pm
Time and money spent on a power source won't be of much benefit unless you also replace the crappy voltage regulators.

In the spirit of the thread why don't you take one of the pics already provided (or off the web), show exactly which regulators you are talking about, then provide some links to replacement voltage regulators that you recommend.
Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 26 Mar 2010, 07:22 pm
In the spirit of the thread why don't you take one of the pics already provided (or off the web), show exactly which regulators you are talking about, then provide some links to replacement voltage regulators that you recommend.

I know I would like that.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 27 Mar 2010, 06:39 am
In the spirit of the thread why don't you take one of the pics already provided (or off the web), show exactly which regulators you are talking about, then provide some links to replacement voltage regulators that you recommend.

I’m afraid any specific suggestion I make will be disparaged as my previous suggestion was. After all, you guys think you know it all.

Some at diyAudio prefer shunt regulators and other like the so-called super regulators. Either of those would be a significant improvement over the cheapo series regulators supplied with the kit. They also have the advantage of being drop in replacements. I prefer ultra low noise LDO regulators. The disadvantage is they are not drop in replacements. They are a different form factor and usually source less current. But, at least for me, the advantage is that they can be sprinkled around to provide clean power to individual or small groups of chips that need clean power that is not contaminated with the noise spewed out by every other part of the circuit. That was the basis for my earlier suggestion that the daughter boards for the DAC and DIR be reworked to include ULN LDO regulators.

I can’t tell what to use because I don’t know what voltages are being used and what input DC voltages are available. Besides, if you are not willing to do PCB layout and SMD soldering, there is no point because, as I said, they are not direct replacements for the existing regulators.

I use Linear regulators. I think they were the first on the market. National also makes them. I mount them on tiny PCBs with the required input, output, and bypass caps making a convenient module that can be added where needed, can be easily replaced, and takes up very little space on the PCB to which it is added.

(http://internet.cybermesa.com/~jmlpartners/images/vr.jpg)

I repeatedly bring up this subject because I am flabbergasted that you are investing considerable time and money in an attempt to turn a sow’s ear into a silk purse but seem to be willing to settle for a burlap bag. The voltage regulator and related components are some of the most critical parts of the circuit. This is what Cirrus has to say about it.

Quote
For applications where the recovered input clock, output on the RMCK pin, is required to be low jitter, use a separate, quite, analog +3.3 V supply for VA, decoupled to AGND. Make certain no digital traces are routed near VA, AGND, or FILT as noise may couple and degrade performance. These pins should be well isolated from switching signals and other noise sources. Extensive use of power and ground planes, ground plane fill in unused areas and surface mount decoupling capacitors are recommended. Decoupling capacitors should be mounted on the same side of the board as the CS8416 to minimize inductance effects, and all decoupling capacitors should be as close to the CS8416 as possible.

They are equally specific about the components in the PLL filter.

Quote
The type of capacitor used for the PLL filter can have a significant effect on receiver performance. Large or exotic film capacitors are not necessary as their leads and the required longer circuit board traces add undesirable inductance to the circuit. Surface mount ceramic capacitors are a good choice because their own inductance is low, and they can be mounted close to the FILT pin to minimize trace inductance. For Crip, a C0G or NPO dielectric is recommended, and for Cflt, an X7R dielectric is preferred.

The Gigawork DAC meets none of those requirements. If you are serious about getting the most performance out of an inexpensive kit that is poorly designed in the first place, than you better get really serious about the modifications you are planning to make, otherwise you are wasting your time. That’s why I suggested you avoid the first two DAC kits pictured in the original post. The photo of the third one is not clear enough to reveal details of the circuit implementation but it looks a lot closer to the ideal then the others.  On the other hand, if you just want to have fun replacing caps and opamps and think that will bring you audio nirvana, have fun. It takes more than simple parts swaps to really improve a digital circuit. It’s your money and your time, do what you want.

A word to the wise: Output caps are there for a purpose; to block DC. Amps don’t like DC. That’s why they often have input caps, but you probably remove those too, don’t you? Signal transformers don’t like DC either, but you probably already know that, don’t you? What you may not know is that some Sigma-Delta DACs have considerable DC offset in their analog output, by design. If you don’t remove the DC in the reconstruction filter or with output caps, you are asking for trouble.

Why is it audiophiles, who can’t read schematics and who don’t read datasheets, think they know more than the engineers who designed the components, drew the schematics, and wrote the datasheets?
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 27 Mar 2010, 08:08 am
I’m afraid any specific suggestion I make will be disparaged as my previous suggestion was. After all, you guys think you know it all.


Jb, no one (in this thread, anyway) is trying to disparage you. I suggest you re-read your first post in this thread vs. all that came before it. You effectively showed up, pulled a Woo and peed on the rug while calling Lebowski a deadbeat for not having the money. Your posts are effectively: don't waste your time with these, or if you do you need to basically gut everything. That perspective is all well and good but it has nothing to do with the purpose of this thread. You seem to not believe that this thread is oriented toward a skill level or diy interest that is not up to searching datasheets, schematics and literally designing pcb's.

If you've read the threads I've linked it's clear that there are folks with a pretty high technical knowledge who do not feel these are crap, but quite the opposite. Why you won't post on diyaudio where the main thread is as I suggested, I don't know. You are bound to have a more robust discussion there. :?

And I've already suggested doing a step by step of your mod so that everyone can benefit.

I don't know what else to tell you, and this is as much I wish to say about it.



Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 27 Mar 2010, 04:41 pm
I’m afraid any specific suggestion I make will be disparaged as my previous suggestion was. After all, you guys think you know it all.

Some at diyAudio prefer shunt regulators and other like the so-called super regulators. Either of those would be a significant improvement over the cheapo series regulators supplied with the kit. They also have the advantage of being drop in replacements. I prefer ultra low noise LDO regulators. The disadvantage is they are not drop in replacements. They are a different form factor and usually source less current. But, at least for me, the advantage is that they can be sprinkled around to provide clean power to individual or small groups of chips that need clean power that is not contaminated with the noise spewed out by every other part of the circuit. That was the basis for my earlier suggestion that the daughter boards for the DAC and DIR be reworked to include ULN LDO regulators.

I can’t tell what to use because I don’t know what voltages are being used and what input DC voltages are available. Besides, if you are not willing to do PCB layout and SMD soldering, there is no point because, as I said, they are not direct replacements for the existing regulators.

I use Linear regulators. I think they were the first on the market. National also makes them. I mount them on tiny PCBs with the required input, output, and bypass caps making a convenient module that can be added where needed, can be easily replaced, and takes up very little space on the PCB to which it is added.

(http://internet.cybermesa.com/~jmlpartners/images/vr.jpg)

I repeatedly bring up this subject because I am flabbergasted that you are investing considerable time and money in an attempt to turn a sow’s ear into a silk purse but seem to be willing to settle for a burlap bag. The voltage regulator and related components are some of the most critical parts of the circuit. This is what Cirrus has to say about it.

They are equally specific about the components in the PLL filter.

The Gigawork DAC meets none of those requirements. If you are serious about getting the most performance out of an inexpensive kit that is poorly designed in the first place, than you better get really serious about the modifications you are planning to make, otherwise you are wasting your time. That’s why I suggested you avoid the first two DAC kits pictured in the original post. The photo of the third one is not clear enough to reveal details of the circuit implementation but it looks a lot closer to the ideal then the others.  On the other hand, if you just want to have fun replacing caps and opamps and think that will bring you audio nirvana, have fun. It takes more than simple parts swaps to really improve a digital circuit. It’s your money and your time, do what you want.

A word to the wise: Output caps are there for a purpose; to block DC. Amps don’t like DC. That’s why they often have input caps, but you probably remove those too, don’t you? Signal transformers don’t like DC either, but you probably already know that, don’t you? What you may not know is that some Sigma-Delta DACs have considerable DC offset in their analog output, by design. If you don’t remove the DC in the reconstruction filter or with output caps, you are asking for trouble.

Why is it audiophiles, who can’t read schematics and who don’t read datasheets, think they know more than the engineers who designed the components, drew the schematics, and wrote the datasheets?
jb, you seem to be obsessed with dissing this entire thread.  Why don't you either put up or take your elitist views elsewhere.  You have been asked on several occasions to add to the discourse and you have yet to do so.  A tutorial would be a good thing from you.

As to your diatribe about this DAC... we don't care.  For some of us enjoyment is in the doing and sharing, not in dismissive attitudes and condescention.

FYI, the Cirrus DAC takes care of DC offset internally.  The opamps that I am using are very low offset and the piece of gear that this unit feeds has a VHQ coupling capacitor at the input stage.  That ios why I took out the coupling caps in the unit... I don't need them in my application.  I assume that anyone that is reading these pages will be smart enough to know that you can't send DC to a preamp and make it happy.

Do us all a favor and either add somethig constructive to the conversation or go away.  Better yet, become an entrepreneur and whip up a batch of your super-duper gimswitches and offer them for sale.  If the price were right I would buy some.  Teach, don't lecture.

Like you said: a word to the wise.  Some of us like pork. 

My .02.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: TrungT on 27 Mar 2010, 05:54 pm
Dave
Well said  :thumb:
Wish I can type that good  :wink:
Thanks for the mod tips
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 27 Mar 2010, 07:29 pm
You have been asked on several occasions to add to the discourse and you have yet to do so.  A tutorial would be a good thing from you.

Exactly what kind of tutorial would you like?

Title: Re: DIY DAC Kits and Easy Mods
Post by: Occam on 27 Mar 2010, 10:24 pm

(http://www.audiocircle.com/image.php?id=28107)

This captures most of the mods in one picture
.........
I auditioned opamps:
   
    AD826 - forward and hard, almost brittle sounding
    OPA2134 - smooth but not very articulate
    LM4562 - woofy and vague sounding, hard to define some instruments especially in the mid
          to upper bass
    Twin OPA627 (Gigawork) - as always very good with nice bass and smooth yet detailed, very
          dynamic

There you have it so far.  The journey will continue............................... ......

Dave

Dave,

Based on the above picture, can I assume that both channel's differential outputs are handled(combined/'single ended') by a single dual opamp, and that the output buffering for both channels are handled by the other (no longer there) dual opamp? or did you reroute the signals to use that single dual opamp?
If your mods didn't require that signal rerouting an alternative might be replacing the opamp recieving the differential outputs with an OPA2107 (or that wonderfully priced dual OPA627) and using a LM4562/LME49720 for the output dual opamp. This would also facilitate removing all signal coupling caps. While I do like the sound of the OPA627, I subjectively prefer the sound  of a 2107/627 coupled to a LM4562. Its not necessarily better, just voiced differently.

Quote
.... (to jb) Better yet, become an entrepreneur and whip up a batch of your super-duper gimswitches and offer them for sale.  If the price were right I would buy some.
Great suggestion! I'm in for that group buy. The LT176x/196x LDO regulators are excellent.

Regards,
Paul
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 28 Mar 2010, 04:01 am
Exactly what kind of tutorial would you like?
Anything that you would consider doping to educate us ignorant audiophiles would be a good start.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 28 Mar 2010, 04:16 am
Dave,

Based on the above picture, can I assume that both channel's differential outputs are handled(combined/'single ended') by a single dual opamp, and that the output buffering for both channels are handled by the other (no longer there) dual opamp? or did you reroute the signals to use that single dual opamp?
If your mods didn't require that signal rerouting an alternative might be replacing the opamp recieving the differential outputs with an OPA2107 (or that wonderfully priced dual OPA627) and using a LM4562/LME49720 for the output dual opamp. This would also facilitate removing all signal coupling caps. While I do like the sound of the OPA627, I subjectively prefer the sound  of a 2107/627 coupled to a LM4562. Its not necessarily better, just voiced differently.
Great suggestion! I'm in for that group buy. The LT176x/196x LDO regulators are excellent.

Regards,
Paul
Paul, the output is summed to one dual opamp and then to a buffer on the stock board.  What you see is a dual OPA627 board that was also sourced from Gigawork.  The boards sell for $29.95 for a pair of the dual /627 boards and cost $6.00 to get them from Hong Kong to Albuquerque.  A heck of a deal.  I tried several different opamps: OPA2604, OPA2134, LM4562 and AD826.  In my rig - Dodd battery powered Buffer and Stereo amp - the OPA627 sounded the best as judged by me and 4 out of 4 guys that heard the opamps.  The LM4562 was second choice and the OPA2134 third.  The AD was just hard sounding in my system.

I am a 'less is more' guy and eliminating the buffer lifted another veil from the soundstage and it got wider and deeper with improved timbre.  For what I've got in this DAC, it doesn't suck.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: Occam on 28 Mar 2010, 04:48 am
....
I am a 'less is more' guy and eliminating the buffer lifted another veil from the soundstage and it got wider and deeper with improved timbre.  For what I've got in this DAC, it doesn't suck.

Dave

Indeed, and obviously opamp eugenics is fraught with cosmic humor; one might get the worst of combined characteristics, rather than the best. But OPA 2107 works particularly well with the LM4562, fed from the CS4398, and the architecture seems to allow a simple swap of opamps in the extant sockets, and a bypass of signal coupling caps. IMO, preferable to a Zapfilter handling the CS4398 outputs.

....  during the height of eugenics popularity among the English, a lady suggested to her fellow dinner guest, George Bernard Shaw that they should reproduce for Society's benefit, to which he responded -
'But Madame, suppose they get MY looks, and YOUR brains?'

Regards,
Paul
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 28 Mar 2010, 05:02 am
Indeed, and obviously opamp eugenics is fraught with cosmic humor; one might get the worst of combined characteristics, rather than the best. But OPA 2107 works particularly well with the LM4562, fed from the CS4398, and the architecture seems to allow a simple swap of opamps in the extant sockets, and a bypass of signal coupling caps. IMO, preferable to a Zapfilter handling the CS4398 outputs.

....  during the height of eugenics popularity among the English, a lady suggested to her fellow dinner guest, George Bernard Shaw that they should reproduce for Society's benefit, to which he responded -
'But Madame, suppose they get MY looks, and YOUR brains?'

Regards,
Paul
Paul, thanks for the insight.  I have a couple of these units here that I am going to mod for some folks.  I'll order in a few of the OPA 2107 opamps and give them a try.  I have a half a dozen of the Nationals.  Maybe that 2107 will help with the bloat that we heard with the single 4562. 

That is what I love about this stuff: the learn by doing aspect.  I'm a victim of POOGE-mania.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 28 Mar 2010, 05:48 am
Anything that you would consider doping to educate us ignorant audiophiles would be a good start.

I tried that. I described the importance of voltage regulators in DAC design quoting from the Cirrus datasheet. You complained that I was preaching. Before that I explained that unless you replace the voltage regulators on the Gigawork DAC you'll feed the DAC chip a dirty clock and dirty power and changing caps and opamps will not clean it up. I also ponted out the the Gigawork DAC did not meet Cirrus' advice regarding component selection and PCB layout and was a poor chice for further modding. Wushuliu didn't like hearing any of that. I think you guys just don't like hearing that you picked the wrong DAC. As I said, I think the third DAC pictured in the original post would have been a much better starting point for further modification. There was less wrong with it to begin with.

Pick a topic and I'll share what I know. It appears no one here is comforatable with surface mount and all high performance digital audio hardware today is surface mount. That kinda rules out hardware discussions. You should be happy it hasn't transitioned to BGA or "chips without pins." It's no more difficult to work with than SMD, or so I'm told, but you need specialized equipment. That will leave hobbyists out inthe cold. Maybe you want to talk about software. I do that too.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 28 Mar 2010, 08:10 am
Anything that you would consider doping to educate us ignorant audiophiles would be a good start.

Dave

It's kind of like Jay Kim: the Early Years, on PE!
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 28 Mar 2010, 03:19 pm
I tried that. I described the importance of voltage regulators in DAC design quoting from the Cirrus datasheet. You complained that I was preaching. Before that I explained that unless you replace the voltage regulators on the Gigawork DAC you'll feed the DAC chip a dirty clock and dirty power and changing caps and opamps will not clean it up. I also ponted out the the Gigawork DAC did not meet Cirrus' advice regarding component selection and PCB layout and was a poor chice for further modding. Wushuliu didn't like hearing any of that. I think you guys just don't like hearing that you picked the wrong DAC. As I said, I think the third DAC pictured in the original post would have been a much better starting point for further modification. There was less wrong with it to begin with.

Pick a topic and I'll share what I know. It appears no one here is comforatable with surface mount and all high performance digital audio hardware today is surface mount. That kinda rules out hardware discussions. You should be happy it hasn't transitioned to BGA or "chips without pins." It's no more difficult to work with than SMD, or so I'm told, but you need specialized equipment. That will leave hobbyists out inthe cold. Maybe you want to talk about software. I do that too.
jb, I think that you are missing my point on this.  This is a DIY thread about taking some cheap, run of the mill DACs and doing some simple mods on them to improve their performance.  There is no one on this thread that I know of that assumes that it can provode SOTA performance.  All we want to do is make something that is OK, better... good enough th be a DAC that we don't hate listening to and to have a little satisfaction in know that it sounds better because we had our hands in it.  No more, no less.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: Atlplasma on 28 Mar 2010, 04:34 pm
Well put, Dave. I have the Gigawork dac and posted a few times on the DIY thread that deals with this device. Even though I'm a novice at this stuff, I got lots of support from the more experienced DIY modders. My impression was that this threat had the same sort of goals. That is, it was a resource for sharing information and practical instructions on how to make some modest improvements in an affordable piece of technology.

While I'm impressed by JB's  ability to master a significant amount of technical information, I don't feel his posts are really adding much to the thread. (Sorry, JB.) I suppose many of us only have a limited amount of time to spend on this hobby. I certainly would like to know a great deal more about the technical side of things, but I have to acquire that information incrementally--and perhaps through a bit of hands-on experience.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 28 Mar 2010, 07:13 pm
jb, I think that you are missing my point on this.  This is a DIY thread about taking some cheap, run of the mill DACs and doing some simple mods on them to improve their performance.  There is no one on this thread that I know of that assumes that it can provode SOTA performance.  All we want to do is make something that is OK, better... good enough th be a DAC that we don't hate listening to and to have a little satisfaction in know that it sounds better because we had our hands in it.  No more, no less.

OK, but I thought SOTA was the goal.

The general consensus seems to be that stock/opamps mod they compete w/ retail anywhere from $600 to $2k range. Once you add transformer outputs, however, all bets are off and you open the vortex that is audio nirvana

With the potential of the chipsets on those cheap DACs there is no reason they can't be modded to give true SOTA performance. If you're happy polishing turds, I'll try not to spoil your fun.
Title: Re: DIY DAC Kits and Easy Mods
Post by: doug s. on 28 Mar 2010, 07:19 pm
OK, but I thought SOTA was the goal.

With the potential of the chipsets on those cheap DACs there is no reason they can't be modded to give true SOTA performance. If you're happy polishing turds, I'll try not to spoil your fun.
jb, all that's being asked of you is to post step-by-step description of mods, w/included marked-up pics for us parts swappers that aren't knowledgeable about the actual curcuits.  similar to what wu has done.  is that so difficult?  comments like polishing turds aren't helpful. 

doug s.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jb on 29 Mar 2010, 07:19 pm
jb, all that's being asked of you is to post step-by-step description of mods, w/included marked-up pics for us parts swappers that aren't knowledgeable about the actual curcuits.  similar to what wu has done.  is that so difficult?

Actually, for me your request is very difficult. I don’t have a Gigawork DAC and I don’t want one. It’s a turd. Had you guys settled on the third DAC in the group presented I might have be curious enough to buy one just to see how far it could go with simple parts swapping and minor circuit changes. The trouble is, with a combined digital IQ in single digits, you guys can’t tell the difference between a diamond-in-the-rough and a turd.

I won’t be posting here anymore because it’s impossible to discern if a poster is seeking the very best or is simply looking for camaraderie with fellow turd polishers.
Title: Re: DIY DAC Kits and Easy Mods
Post by: dBe on 29 Mar 2010, 07:29 pm
Actually, for me your request is very difficult. I don’t have a Gigawork DAC and I don’t want one. It’s a turd. Had you guys settled on the third DAC in the group presented I might have be curious enough to buy one just to see how far it could go with simple parts swapping and minor circuit changes. The trouble is, with a combined digital IQ in single digits, you guys can’t tell the difference between a diamond-in-the-rough and a turd.

I won’t be posting here anymore because it’s impossible to discern if a poster is seeking the very best or is simply looking for camaraderie with fellow turd polishers.
We will be able to tell people that we have the shiniest turd DACs around.  I think I'll have my faceplate engraved "ST-DAC" in your honor.

Buh-bye.

Dave
Title: Re: DIY DAC Kits and Easy Mods
Post by: doug s. on 30 Mar 2010, 01:03 am
Actually, for me your request is very difficult. I don’t have a Gigawork DAC and I don’t want one. It’s a turd. Had you guys settled on the third DAC in the group presented I might have be curious enough to buy one just to see how far it could go with simple parts swapping and minor circuit changes. The trouble is, with a combined digital IQ in single digits, you guys can’t tell the difference between a diamond-in-the-rough and a turd.

I won’t be posting here anymore because it’s impossible to discern if a poster is seeking the very best or is simply looking for camaraderie with fellow turd polishers.
w/o going back thru this thread to dig up your prior posts, i thought you talked about another dac you have worked on.  i was yust saying you could post in-depth tutorial w/pics of what you had done.  while you have made it clear that you do not want to be coming across as a turd polisher, do you really believe it's better to come across as a turd?   better be careful, before someone comes up and starts trying to polish you!  8)

doug s.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 3 Apr 2010, 08:51 am
Not content to leave well enough alone I went and ordered this guy:

(http://www.audiocircle.com/image.php?id=28518)


http://cgi.ebay.com/DAC-kit-AD1865N-K-NOS-1-0-NOS_W0QQitemZ220578977025QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item335b881501#ht_2518wt_1165 (http://cgi.ebay.com/DAC-kit-AD1865N-K-NOS-1-0-NOS_W0QQitemZ220578977025QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item335b881501#ht_2518wt_1165)

going to do the easy mods on Lukasz' Lampizator site:

http://www.lampizator.eu/LAMPIZATOR/REFERENCES/NOS-DAC_AD1865/ad1865.html (http://www.lampizator.eu/LAMPIZATOR/REFERENCES/NOS-DAC_AD1865/ad1865.html)

DAC kit AD1865N-K NOS 1.0 NOS
 
A. DAC AD1865N-K NOS 1.0
    DAC kit construction:
 1. Input : SPDIF (coaxial)
 2. 26C32+CS8414+74HC02+AD1865N-K
 3. NOS (non-oversampling) application
 4. low noise JFET with class A buffer for analog output
 4. 2 stages regulator with LT1084 for digital section
 5. Audio grade components were used.
 6. SIC-SAFCO elect-cap for digital receiving section and ELNA for AD1865 D/A section filtering,
 7. High speed with low resistance D3S rectifier and Military grade resistors were used.
 8. Reserve the analog output from AD1865 chip directly for matching with HDAM, tube driver
      ***Means the kit can output from JFET stage, HDAM stage and Tube buffer stage to suit for you’re listening interests.****
 
B. Power supply
 . 0-9V*2 & 0-18V*2
     
C. PCB size:
     224mm x 145mm with double size gold plated.
 
D. Optional : HDAM kit, tube buffer module from my ebay shop

 
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 11 Apr 2010, 04:27 pm
How does this one compare to Gigawork?

Not content to leave well enough alone I went and ordered this guy:


Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 11 Apr 2010, 05:32 pm
So I wanted to ask a basic question here.

For DAC, if I have the USB input, I can use it to replace the sound card on the laptop when I play MP3 or digital music. 

If I have digital input on my DAC and my CD player has digital out, I can bypass the dac inside the CD player and use the DAC for converting. 

So essentially, I can connect my music server (USB) and CD player (Digital) to DAC and connect the DAC to the Pass B1 Preamp and to the Class D Amp.  Am I understanding the whole scenario correctly?

In the CD player case, a high end DAC will transform a good CD player into a high end CD player.  Is that true?

Thanks!
Title: Re: DIY DAC Kits and Easy Mods
Post by: srb on 11 Apr 2010, 05:55 pm
Am I understanding the whole scenario correctly?

Yes.

In the CD player case, a high end DAC will transform a good CD player into a high end CD player.  Is that true?

It can be!  The CD player has a slight advantage in that the connection between the transport and the internal DAC chip is usually via I2S, and doesn't need to rely on the S/PDIF conversion that is used to transmit digital audio over a digital cable to an external DAC.
 
Also, the inherent jitter (or minute mistiming of the digital signal) sometimes comes into play when making external connections to a DAC.
 
But, in general, most people realize an improvement if the external DAC is of significantly better performance than the internal DAC.
 
Steve
 
 
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 11 Apr 2010, 05:58 pm
That makes sense.  I bought a DAC with USB input for my laptop.  I didn't understand why a DAC needs digital input.  Beyond the CD player scenario, what other devices would output digital that can connect to a DAC?


Yes.
 
It can be!  The CD player has a slight advantage in that the connection between the transport and the internal DAC chip is usually via I2S, and doesn't need to rely on the S/PDIF conversion that is used to transmit digital audio over a digital cable to an external DAC.
 
Also, the inherent jitter (or minute mistiming of the digital signal) sometimes comes into play when making external connections to a DAC.
 
But, in general, most people realize an improvement if the external DAC is of significantly better performance than the internal DAC.
 
Steve
Title: Re: DIY DAC Kits and Easy Mods
Post by: HAL on 11 Apr 2010, 06:09 pm
Universal Disc Players will give S/PDIF output that is higher resolution than CD for DVD-A or DVD recordings.  This is for two channel playback.
Title: Re: DIY DAC Kits and Easy Mods
Post by: srb on 11 Apr 2010, 06:11 pm
Beyond the CD player scenario, what other devices would output digital that can connect to a DAC?

Cable TV receivers, Digital Video Recorders (DVR), DVD/Blu-ray players, gaming systems (PS3, XBox, etc.) and HD/Internet radio tuners are some possibilities.
 
Aside from AV Receivers and Processors that have internal DACs that can decode multi-channel Dolby Digital, DTS, Dolby True HD, DTS-HD Master Audio, etc., most all standalone DACs are 2 channel, and any of the multi-channel sources listed above would need to be set to output 2 channel PCM digital audio to be used with them.
 
Steve
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 11 Apr 2010, 06:40 pm
How does this one compare to Gigawork?

Hasn't arrived yet. Anything from HK/China takes several weeks.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 11 Apr 2010, 06:42 pm
This one looks great but I'm a little hesitate that it doesn't have a USB input which means I cannot use it with my computer sources. ;(

Be sure to share your perspectives.  Did you order the one with a transformer? 

Hasn't arrived yet. Anything from HK/China takes several weeks.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 11 Apr 2010, 06:45 pm
My current source is actually an old Pioneer Universal Player that I use it and MP3 on computers.  So my best bet would be to get a dac with USB and digital inputs.  Well, wait for finishing the Class D and Pass B1 first. ;)


Cable TV receivers, Digital Video Recorders (DVR), DVD/Blu-ray players, gaming systems (PS3, XBox, etc.) and HD/Internet radio tuners are some possibilities.
 
Aside from AV Receivers and Processors that have internal DACs that can decode multi-channel Dolby Digital, DTS, Dolby True HD, DTS-HD Master Audio, etc., most all standalone DACs are 2 channel, and any of the multi-channel sources listed above would need to be set to output 2 channel PCM digital audio to be used with them.
 
Steve
Title: Re: DIY DAC Kits and Easy Mods
Post by: HT cOz on 14 Apr 2010, 09:03 pm
Hasn't arrived yet. Anything from HK/China takes several weeks.

Let us know your progress.  That one does sound interesting!

What all is needed to get it working?
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 20 Apr 2010, 01:25 pm
Has anyone compared these DIY kits to the Maverick Audio DAC?
Title: Re: DIY DAC Kits and Easy Mods
Post by: HT cOz on 20 Apr 2010, 05:04 pm
Any thoughts on this DAC?
(http://www.audiocircle.com/image.php?id=29253)

http://cgi.ebay.com/24bit-192KHz-DAC-DIY-KIT-FULL-ASSEMBLED-KIT-Lampucera-/120551270538?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1c116a688a

This is about where my tiny budget for these things are.  My source is a modded Olive Musica with BNC output.  I think its internal dac isn't that great and that one of these kits might be a step up.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 22 Apr 2010, 11:15 pm
Any thoughts on this DAC?
(http://www.audiocircle.com/image.php?id=29253)

http://cgi.ebay.com/24bit-192KHz-DAC-DIY-KIT-FULL-ASSEMBLED-KIT-Lampucera-/120551270538?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1c116a688a

This is about where my tiny budget for these things are.  My source is a modded Olive Musica with BNC output.  I think its internal dac isn't that great and that one of these kits might be a step up.

Don't know how it sounds stock, but the links I provided on the first page are for an earlier version and seems to need more modding than the larger gigawork. But for the money, why not?

here's another cheap one that's just come out. Haven't heard it, but it doesn't use opamps in the
output stage like the above and the seller seems to have good quality dac's (one of which is on the way). For the
money it can't hurt to try, and you can let us know what you think!

http://cgi.ebay.com/Special-offer-TDA1543-4-DAC-4-0-NOS-DAC-Kit-CS8412-/220589925703?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item335c2f2547


(http://www.audiocircle.com/image.php?id=29378)
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 22 Apr 2010, 11:19 pm
Let us know your progress.  That one does sound interesting!

What all is needed to get it working?

A transformer for the power supply (probably the R-core that I am using currently, pictured earlier in the thread), and wiring for the coaxial input.
Title: Re: DIY DAC Kits and Easy Mods
Post by: SET Man on 23 Apr 2010, 04:31 am
...

here's another cheap one that's just come out. Haven't heard it, but it doesn't use opamps in the
output stage like the above and the seller seems to have good quality dac's (one of which is on the way). For the
money it can't hurt to try, and you can let us know what you think!

http://cgi.ebay.com/Special-offer-TDA1543-4-DAC-4-0-NOS-DAC-Kit-CS8412-/220589925703?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item335c2f2547


(http://www.audiocircle.com/image.php?id=29378)

Hey!

    I have this DAC in my system right now. Bought from this seller, great seller by the way. :D

    This DAC use 4 TDA1543 DAC chips running in paralleled. The output come directly off those chips. There is no opamp or buffer after the DAC chips. Simple! I like it.

  The DAC uses lot of good quality component despite the price. Still I only did 2 upgrades to it. 1. Changed diodes to Schottky type 2. Changed the output caps (22uf) to Russian K73-16 22uf 63V with Jensen PIO Copper as by pass caps.

     Definitely the output cap upgrade made the biggest improvement. The stock caps sounds horrible. But I know NOS DAC so that was the first thing I looked at to upgrade.

    So far a great NOS DAC. But not for everyone. It won't do detail especially in the high like 24/96+ DAC. But I'm a fan of NOS DAC of which I feel sound more analog playing Red Book CD :D I found most 24/96+ DAC sound unease especially in the high that sometime can sound hyper unnatural. Of course they are some exception of good 24/96+ DACs out there.

    Anyway, I will take some pictures and post them here soon.

Take care,
Buddy :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Apr 2010, 04:49 am
Hey!

    I have this DAC in my system right now. Bought from this seller, great seller by the way. :D

    This DAC use 4 TDA1543 DAC chips running in paralleled. The output come directly off those chips. There is no opamp or buffer after the DAC chips. Simple! I like it.

  The DAC uses lot of good quality component despite the price. Still I only did 2 upgrades to it. 1. Changed diodes to Schottky type 2. Changed the output caps (22uf) to Russian K73-16 22uf 63V with Jensen PIO Copper as by pass caps.

     Definitely the output cap upgrade made the biggest improvement. The stock caps sounds horrible. But I know NOS DAC so that was the first thing I looked at to upgrade.

    So far a great NOS DAC. But not for everyone. It won't do detail especially in the high like 24/96+ DAC. But I'm a fan of NOS DAC of which I feel sound more analog playing Red Book CD :D I found most 24/96+ DAC sound unease especially in the high that sometime can sound hyper unnatural. Of course they are some exception of good 24/96+ DACs out there.

    Anyway, I will take some pictures and post them here soon.

Take care,
Buddy :thumb:

Sweet! Thanks for the feedback and the mod tips! I have yet to hear a TDA154X  DAC, so I may just get this one down the road just to try it out...
Title: Re: DIY DAC Kits and Easy Mods
Post by: SET Man on 24 Apr 2010, 12:40 am
Sweet! Thanks for the feedback and the mod tips! I have yet to hear a TDA154X  DAC, so I may just get this one down the road just to try it out...

Hey!

     No problem. :D

     And here is my NOS DAC Kit with 4 TDA1543 D/A chips running in paralleled.

(http://farm5.static.flickr.com/4030/4545992311_38ca2ace34_o.jpg)
     "I am completely operational, and all my circuits are functioning perfectly."

(http://farm5.static.flickr.com/4043/4545992437_5ebf5993dc_o.jpg)

The PCB board fitted in an IKEA "BJURON" wooden planter. With kit project I always find that finding enclosure for the kit is the hard part sometime. I looked around and came across thie IKEA wooden planter. The inside was almost 1/8" too short so I had to sand off the PCB and the inside of the box with Dremal  to make it fit. This box measure 6.25X6.25X5". There's a bigger box of the same type but it will be too big.

(http://farm5.static.flickr.com/4050/4545992571_bc6f93d899_o.jpg)

The back with BNC and Optical input and output. I didn't put ON/OFF switch yet... forgot to get one.  :icon_lol: Fitting those jacks was a bit tricky since I can't drill from the inside. So I had to make recesses into the box to make them fit. Unfortunately I made mistake with the hole in the middle and have to patch it up. I guess I could make a label about the DAC and cover it. :wink:

(http://farm5.static.flickr.com/4048/4546626488_a2cb1fd9ef_o.jpg)

   Underneath, the transformer is a Signal Transformer "Flathead" LP-20-1200 0-10V 1-10V 24VA. As mentioned before I did 2 upgrades on this. 1. Stock diodes to Schottky type. 2. Stock caps to Russian K73-16 22uf 63V with Jensen PIO Copper as by pass.

(http://farm5.static.flickr.com/4057/4533579740_a25cca978d_o.jpg)

   Here's the DAC in my system.

   Anyway the original output caps was ELNA CE-BP 22uf 50V with small green of which I think is ERO .1uf 100V used as by pass cap. Overall the combination of both stocks caps sound harsh, bright and thin side without any body or dimension even after 50 hours of break-in using my cable box and feed the TV. I first try it without the ERO .1uf by pass caps solved the brightness problem but the sound turn dark and flat.

    So, after a little research I went with a matched pair of Russian K73-16 also picked up off eBay from a very good seller. Surprisingly the K73-16 sound very good by themselves. But was a bit flat and can use a little more open top. So, this is where a by pass cap came in. I tried a few that I have left from previous projects and upgrade, from cheap orange drop to MIT RTX ranging from .1uf to .47uf. But I settled on .22uf Jensen copper PIO cap. At .22uf it fall in at 1% of the 22uf main cap which is just fine. BTW... this is my favorite signal cap I used this type in both my pre and amp.

   As for the sound. Well, I haven't have much time on it yet. But so far it sound very good. Playing CD it sound very analog-like. Very smooth with sound stage the a bit farther back then some of the 24/96+ DAC I've heard. I'm not into the "in your face" sound so this fit me well. But it can lack a bit of dynamic compared to opamp or tube buffered output DAC. Well, I don't mind that.

   I like the sound of NOS DAC playing CD. And this DAC is very nice simple NOS DAC. No OPAMP or buffer after the DAC chip, the I/V is passive.  So this little inexpensive DAC will stay in my system for a while.

    It is a different sound than the 24/96+ DACs out there. Although there some exceptions but not many.

   Well, if anyone else using this DAC I would love to hear how it sound in your system. :D

Take care,
Buddy :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: HT cOz on 24 Apr 2010, 10:42 pm
Does anyone have any idea what to expect if you were to go all out with raindrop_hui on something like this? http://cgi.ebay.com/Dual-DAC-AD1955-AD1896-HDAM-x-3-pairs-/220594293030?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item335c71c926

Title: Re: DIY DAC Kits and Easy Mods
Post by: Occam on 9 May 2010, 06:08 pm
FWIW, the always interesting Lukaz has been mucking about with these inexpensive DACs -
http://www.lampizator.eu/LAMPIZATOR/LAMPUCERA/CD%20DAC%20Lampucera%20lampizator.html

Interesting read, but I do wish he'd keep the leads of his decoupling caps shorter...
For those looking to simplify their opamp outputs, removing coupling caps and biasing a bipolar input opamp deeper into class A and removing the ouput offset -

(http://www.audiocircle.com/image.php?id=30172)

http://www.lampizator.eu/LAMPIZATOR/LAMPUCERA/MAX/opamped_lampucera.html

Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 20 May 2010, 07:11 am
Hey, I just got some of those K73-16 caps for my B1 buffer. Only in 10 min. and I like them already. Totally unexpected sound. Thought they were going to be harsh, but they are sweet as honey.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 20 May 2010, 07:18 am
FWIW, the always interesting Lukaz has been mucking about with these inexpensive DACs -
http://www.lampizator.eu/LAMPIZATOR/LAMPUCERA/CD%20DAC%20Lampucera%20lampizator.html

Interesting read, but I do wish he'd keep the leads of his decoupling caps shorter...
For those looking to simplify their opamp outputs, removing coupling caps and biasing a bipolar input opamp deeper into class A and removing the ouput offset -

(http://www.audiocircle.com/image.php?id=30172)

http://www.lampizator.eu/LAMPIZATOR/LAMPUCERA/MAX/opamped_lampucera.html

What I would love is if someone would actually do a step by step of his lampizator (or the minilamp that he's now raving about), I'm not an EE type and although I can follow the schematics if I try really hard I need actual visuals to keep me from screwing up. His minilampizator looks intriguing.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 20 May 2010, 07:23 am
Let us know your progress.  That one does sound interesting!

What all is needed to get it working?

Finally got it about 10 days ago. Looks really nice, better quality than the gigawork. Just needs a transformer, coaxial input, that's it. Since my B1 has turned out even better than I'd hoped, I'll get this project going soon.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 20 May 2010, 07:26 am
Hey!

     No problem. :D

     And here is my NOS DAC Kit with 4 TDA1543 D/A chips running in paralleled.

(http://farm5.static.flickr.com/4030/4545992311_38ca2ace34_o.jpg)
     "I am completely operational, and all my circuits are functioning perfectly."

(http://farm5.static.flickr.com/4043/4545992437_5ebf5993dc_o.jpg)

The PCB board fitted in an IKEA "BJURON" wooden planter. With kit project I always find that finding enclosure for the kit is the hard part sometime. I looked around and came across thie IKEA wooden planter. The inside was almost 1/8" too short so I had to sand off the PCB and the inside of the box with Dremal  to make it fit. This box measure 6.25X6.25X5". There's a bigger box of the same type but it will be too big.

(http://farm5.static.flickr.com/4050/4545992571_bc6f93d899_o.jpg)

The back with BNC and Optical input and output. I didn't put ON/OFF switch yet... forgot to get one.  :icon_lol: Fitting those jacks was a bit tricky since I can't drill from the inside. So I had to make recesses into the box to make them fit. Unfortunately I made mistake with the hole in the middle and have to patch it up. I guess I could make a label about the DAC and cover it. :wink:

(http://farm5.static.flickr.com/4048/4546626488_a2cb1fd9ef_o.jpg)

   Underneath, the transformer is a Signal Transformer "Flathead" LP-20-1200 0-10V 1-10V 24VA. As mentioned before I did 2 upgrades on this. 1. Stock diodes to Schottky type. 2. Stock caps to Russian K73-16 22uf 63V with Jensen PIO Copper as by pass.

(http://farm5.static.flickr.com/4057/4533579740_a25cca978d_o.jpg)

   Here's the DAC in my system.

   Anyway the original output caps was ELNA CE-BP 22uf 50V with small green of which I think is ERO .1uf 100V used as by pass cap. Overall the combination of both stocks caps sound harsh, bright and thin side without any body or dimension even after 50 hours of break-in using my cable box and feed the TV. I first try it without the ERO .1uf by pass caps solved the brightness problem but the sound turn dark and flat.

    So, after a little research I went with a matched pair of Russian K73-16 also picked up off eBay from a very good seller. Surprisingly the K73-16 sound very good by themselves. But was a bit flat and can use a little more open top. So, this is where a by pass cap came in. I tried a few that I have left from previous projects and upgrade, from cheap orange drop to MIT RTX ranging from .1uf to .47uf. But I settled on .22uf Jensen copper PIO cap. At .22uf it fall in at 1% of the 22uf main cap which is just fine. BTW... this is my favorite signal cap I used this type in both my pre and amp.

   As for the sound. Well, I haven't have much time on it yet. But so far it sound very good. Playing CD it sound very analog-like. Very smooth with sound stage the a bit farther back then some of the 24/96+ DAC I've heard. I'm not into the "in your face" sound so this fit me well. But it can lack a bit of dynamic compared to opamp or tube buffered output DAC. Well, I don't mind that.

   I like the sound of NOS DAC playing CD. And this DAC is very nice simple NOS DAC. No OPAMP or buffer after the DAC chip, the I/V is passive.  So this little inexpensive DAC will stay in my system for a while.

    It is a different sound than the 24/96+ DACs out there. Although there some exceptions but not many.

   Well, if anyone else using this DAC I would love to hear how it sound in your system. :D

Take care,
Buddy :thumb:

Beautiful build by the way.

So is the stylus still good on that old turntable or what?  :wink:
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 May 2010, 06:43 pm
The AD1865 DAC is up and running. I've more or less followed the Lampizator mods, plus a few extra. As has been noted both on the Lampizator site and on diyaudio w/ the Andrea Ciuoffoli DAC (which the ebay AD1865 is partly based on) the sound is a little dark. I didn't listen to it stock so I can only imagine it's even more so out of the box. However, all the mods have opened it up some. It's a very different sound from the gigawork and I will need some time to really decide if I like it or not.

It does have a more 'natural' tone, more intimate, the HF is slightly rolled off at the top. The bass is very prominent. It is definitely more balanced tonally than my gigawork. Whether this is due to the values I used for the gigawork/tranformer mod or just inherent in the DAC, I don't know, but the AD1865 certainly wins in that regard.

The gigawork is slightly more on the solid state sound side of the spectrum. The AD1865, on the tube side. I think that's a quick way to sum it up. More info and thoughts to come.

(http://www.audiocircle.com/image.php?id=30717)





Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 25 May 2010, 07:51 pm
Absolutely!  Any time... I play well with others (mostly see: http://www.audiocircle.com/index.php?topic=79128.new;topicseen#new ) and I share my toys.

Dave

Hey Dave, I've been listening to the AD1865 DAC I mentioned above and it' very promising so far. I really like it, but I am sure it can be improved. My biggest gripe so far is it's a little recessed in the HF. Anyhoos, I'm no expert on this stuff but usually a place to start w/ mods are the output caps. I notice with the schematic that the jfet output stage has a 100 ohm resitor followed by a 47uf cap. Is this some kind of filter? Any way to alter these values to benefit? Just curious... :scratch:



(http://www.audiocircle.com/image.php?id=30793)




Title: Re: DIY DAC Kits and Easy Mods
Post by: jtwrace on 26 May 2010, 02:47 pm
That was a quick 60 days. 
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 26 May 2010, 06:10 pm

That was a quick 60 days.

Moving sucks  :evil:
Title: Re: DIY DAC Kits and Easy Mods
Post by: SET Man on 27 May 2010, 01:14 am
Hey, I just got some of those K73-16 caps for my B1 buffer. Only in 10 min. and I like them already. Totally unexpected sound. Thought they were going to be harsh, but they are sweet as honey.

Hey!

   That is what I'm hearing too. Better than I expected especially for the price. Maybe we should keep this quiet to keep the price of these cap low, eh?  :shh:

Beautiful build by the way.

So is the stylus still good on that old turntable or what?  :wink:

   Thanks :D

    Old turntable? You mean the old talking machine? Actually you have to change the steel needle after every play. Reusing the steel needle will damage the old 78rpm shellac record. :D

Take care,
Buddy :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: stokessd on 28 May 2010, 02:33 am
jb, I think that you are missing my point on this.  This is a DIY thread about taking some cheap, run of the mill DACs and doing some simple mods on them to improve their performance.  There is no one on this thread that I know of that assumes that it can provode SOTA performance.  All we want to do is make something that is OK, better... good enough th be a DAC that we don't hate listening to and to have a little satisfaction in know that it sounds better because we had our hands in it.  No more, no less.

Dave


I think with some simple mods, this DAC has the potential to get quite close to SOTA.  The chip set is certainly capable of it.  The DIP adapters are a bit of a bummer from a good grounding and high speed signal integrity standpoint, but that said, this circuit has more right about it than wrong. 

With respect to regulators, if you don't like the run of the mill LM317 class regulators, you can drop in some Linear Tech 1086's and the like (The LT equivalent 317's), for a bit of a performance increase.  But you will be limited to the benefit any regulator can give you when the chips are hung up in the air on the DIP adapters.  Judicious capacitor bypassing will help you more than regulator changing.  you need ceramic caps right up next to the pins.  The one thing that should be watched closely is the power feeding that reclocking oscillator.  That's where you need the cleanest purest power in the whole unit.  Fortunately that's also easy to do with a little finesse. 

The most interesting thing about this design, it that the circuitry is so well thought out, and even the op-amps have been pretty well selected for good sound (I can't complain about the OPA627's that came with my unit), but they have crummy electrolytic caps in the signal path.  I can live with the second buffer op-amp, but the caps have to go.  On the next board turn, if they were to  put some reasonable polyprop ones in there, the unit would be a real world-beater at $120 nekkid or $250 with enclosure. 

Myself, I built a similar design with Lundahl LL1690's serving up the analog, and that is really heaven vs. the op-amps.  My design also gets the chips down against a ground plane and the decoupling caps close close close. 

In summary, this is a hell of a steal at $120.  A few simple mods and you are firmly in the land of diminishing returns. 

Sheldon

Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 28 May 2010, 08:25 am

I think with some simple mods, this DAC has the potential to get quite close to SOTA.  The chip set is certainly capable of it.  The DIP adapters are a bit of a bummer from a good grounding and high speed signal integrity standpoint, but that said, this circuit has more right about it than wrong. 

With respect to regulators, if you don't like the run of the mill LM317 class regulators, you can drop in some Linear Tech 1086's and the like (The LT equivalent 317's), for a bit of a performance increase.  But you will be limited to the benefit any regulator can give you when the chips are hung up in the air on the DIP adapters.  Judicious capacitor bypassing will help you more than regulator changing.  you need ceramic caps right up next to the pins.  The one thing that should be watched closely is the power feeding that reclocking oscillator.  That's where you need the cleanest purest power in the whole unit.  Fortunately that's also easy to do with a little finesse. 

The most interesting thing about this design, it that the circuitry is so well thought out, and even the op-amps have been pretty well selected for good sound (I can't complain about the OPA627's that came with my unit), but they have crummy electrolytic caps in the signal path.  I can live with the second buffer op-amp, but the caps have to go.  On the next board turn, if they were to  put some reasonable polyprop ones in there, the unit would be a real world-beater at $120 nekkid or $250 with enclosure. 

Myself, I built a similar design with Lundahl LL1690's serving up the analog, and that is really heaven vs. the op-amps.  My design also gets the chips down against a ground plane and the decoupling caps close close close. 

In summary, this is a hell of a steal at $120.  A few simple mods and you are firmly in the land of diminishing returns. 

Sheldon

Thanks for your thoughts Sheldon.

I have just replaced the Panasonic FCs in the AD1865 DAC w/ Os-cons, and clearly it's what I should have done in the first place; the 'dark' sound is all gone and what I am hearing now is really, really good. Over the next few weeks I'll compare the two DACs. I think they appeal to different tastes. But this AD1865 I think just might hold it's own against the Gigawork w/ tranny mod...

playing w/ dacs is fun. 8)

Title: Re: DIY DAC Kits and Easy Mods
Post by: Kwikas on 29 May 2010, 05:46 am
Hi Guys.

First post here and I came across this thread while googling DAC's so I hope you wont mind if I drop in and ask a few questions.

I'm interested in finding a DAC that can accept 8 channels of spdif in. Are any of the ones you are talking about modding in this thread capable of doing this? I suspect they're all 2 channel but would appreciate knowing if this is the case.

The DAC I'm after is for home cinema (obviously) but I can't seem to find anything that suits what I'm after. Perhaps I'll have to get 4 x 2 channel DAC's but I'm hoping you may be able to offer up some assistance.

Thanks a lot.
Title: Re: DIY DAC Kits and Easy Mods
Post by: stokessd on 29 May 2010, 01:41 pm
Hi Guys.

First post here and I came across this thread while googling DAC's so I hope you wont mind if I drop in and ask a few questions.

I'm interested in finding a DAC that can accept 8 channels of spdif in. Are any of the ones you are talking about modding in this thread capable of doing this? I suspect they're all 2 channel but would appreciate knowing if this is the case.

The DAC I'm after is for home cinema (obviously) but I can't seem to find anything that suits what I'm after. Perhaps I'll have to get 4 x 2 channel DAC's but I'm hoping you may be able to offer up some assistance.

Thanks a lot.


The input chip in the gigaworks DAC can take up to 4 inputs (in hardware mode), but that is 4 discrete SPDIF streams you choose from like an input selector, not simultaneously.  SPDIF is a two channel protocol, there is no provision in SPDIF for doing more than two AFAIK.  So you would need to run four streams for eight channels.  Thus four DAC's etc. 

Sheldon
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 29 May 2010, 04:25 pm


The one thing that should be watched closely is the power feeding that reclocking oscillator.  That's where you need the cleanest purest power in the whole unit.  Fortunately that's also easy to do with a little finesse. 

Sheldon

Sheldon, could you elaborate? What would this entail?
Title: Re: DIY DAC Kits and Easy Mods
Post by: stokessd on 30 May 2010, 03:38 am
Sheldon, could you elaborate? What would this entail?


Sure thing.  All oscillators are very sensitive to the power being fed to them.  And as thanks, they toss all sorts of crap back on that power line. 

So you see in the schematic and layout in my latest DAC design (http://getinthewoodchipper.com/?p=302 (http://getinthewoodchipper.com/?p=302), I've got a ceramic cap as near the oscillator terminals as possible, and a big tantalum (100uF) cap right next to that.  The power feeding the oscillator has a resistor in the line, forming an RC filter right at the oscillator.  For my prototype, which you see in the link above, I used a 25ppm oscillator and that filter/decoupling method and called it good. 

But after I finished the prototype, I realized how easy it would be to add a little inverting amp as a noise eater.  I got this idea from Wenzel (the precision oscillator folks), and it's brilliant in areas where you don't need hugely stiff supply rails.  The idea is that a standard three terminal regulator will still have like 100uV of broadband noise on it under the best of conditions, plus the noise from whatever else is barfing into that same line.  If you build a little very low noise amplifier that takes the AC noise component as an input and outputs an equal and opposite signal, the two cancel and you are left with clean power.  The full story is here:  http://www.wenzel.com/documents/finesse.html (http://www.wenzel.com/documents/finesse.html)


So in the schematics and layout of my DAC in the first link, you see the oscillator is fed from the 8421 logic supply and decoupled from it with a resistor and the caps right at the oscillator, then there is a little single transistor NPN amp which is the noise eater.  Sadly my home measurement gear isn't sensitive enough to tell me how good it gets. 

I'm not sure there is an easy way to implement this technique on the little upsampler board, but it certainly is possible.  If memory serves me right, the oscillator in the gigaworks DAC already has a resistor in the power line, so you'd have to add a transistor, a cap and four resistors.  You could build it up as a little daughterboard that is attached behind the oscillator. 

Honestly, I'm not sure how big a return on investment it really is.  I haven't tried it on my prototype DAC.  I've only used it for other projects which aren't audio related.  I added it to the layout because it's so quick and easy and I don't have to populate it if I don't want to.


Sheldon
Title: Re: DIY DAC Kits and Easy Mods
Post by: Kwikas on 31 May 2010, 05:56 am

The input chip in the gigaworks DAC can take up to 4 inputs (in hardware mode), but that is 4 discrete SPDIF streams you choose from like an input selector, not simultaneously.  SPDIF is a two channel protocol, there is no provision in SPDIF for doing more than two AFAIK.  So you would need to run four streams for eight channels.  Thus four DAC's etc. 

Sheldon

Thanks Sheldon. Yes, I'd have to run 4 streams simultaneously. I''ve got that part happening out of my transceiver board. But the DAC part is a lot more difficult.. I'll see whether I can tackle this another way. Cheers
Title: Re: DIY DAC Kits and Easy Mods
Post by: Atlplasma on 2 Jun 2010, 04:09 pm
Hi guys:

After three weeks of waiting, I finally received this DAC today. Unfortunately, the cap at C23 has come loose. It dangling by one of the leads. Can I heat of a drop of solder and reattach it, or does it need to go back? I hate to wait another 3 or 6 weeks (depending on the return policy) to get it up and running.


(http://cgi.ebay.com/2010-version-24bit-192khz-DAC-fully-assembled-kits-/160431534154?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item255a76f04a)
Title: Re: DIY DAC Kits and Easy Mods
Post by: stokessd on 2 Jun 2010, 07:49 pm
I don't have the most recent schematic in front of me, but the older one shows that the cap in question is a bypass caps for the Analog voltages in the receiver chip.  You should try to solder it back in place, but even with nothing there, you should still be fine.


Sheldon
Title: Re: DIY DAC Kits and Easy Mods
Post by: Atlplasma on 2 Jun 2010, 09:01 pm
Thanks Sheldon. Know an easy was to solder a SMD miniature capacitor? Solder paste and a heat gun seems like a possibility. It kind of looks like I should clean up the connection point with a bit of wick before doing anything else.
Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 3 Jun 2010, 02:53 am
So I am totally stumped.  I have the DAC completely hooked up, using Edcor 10k transformers, but I cannot get any sound.  I don't know what could be the problem :(

The only real mod is that I removed the caps after the 4398 and soldered leads from the top of the board to the transformers.  Using 13k resistor and 680uf cap across the primaries and have the standard resistor and cap combo on the secondaries.  I am getting a fairly uniform voltage at the primaries and at the top of the 4398 board - they do not really seem to be jumping with the music, but are different for different tracks (usually between 1.5v-2.5v, which seems right).  I am getting nothing at the secondaries and no sound.  Also, no sound if I bypass the transformer entirely and hook it directly to the rca.  I get a strange descending sweep of the spectrum when I power down, but otherwise no sound. 

I am getting about 5v at pin 22, 4.5v at pin 27, and 3.30 at pin 7 on the 4398 board.  I am getting 5v at the caps following each of the 317 regs.  Another strange thing is that I am getting opposite voltage readings at the same points if I use the ground on the IEC or the ground on the board.

I am getting to my wits end...  Anybody have any ideas?  I am going to post on diyaudio as well, but that thread is more focused on complex issues.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 3 Jun 2010, 03:46 am
So I am totally stumped.  I have the DAC completely hooked up, using Edcor 10k transformers, but I cannot get any sound.  I don't know what could be the problem :(

The only real mod is that I removed the caps after the 4398 and soldered leads from the top of the board to the transformers.  Using 13k resistor and 680uf cap across the primaries and have the standard resistor and cap combo on the secondaries.  I am getting a fairly uniform voltage at the primaries and at the top of the 4398 board - they do not really seem to be jumping with the music, but are different for different tracks (usually between 1.5v-2.5v, which seems right).  I am getting nothing at the secondaries and no sound.  Also, no sound if I bypass the transformer entirely and hook it directly to the rca.  I get a strange descending sweep of the spectrum when I power down, but otherwise no sound. 

I am getting about 5v at pin 22, 4.5v at pin 27, and 3.30 at pin 7 on the 4398 board.  I am getting 5v at the caps following each of the 317 regs.  Another strange thing is that I am getting opposite voltage readings at the same points if I use the ground on the IEC or the ground on the board.

I am getting to my wits end...  Anybody have any ideas?  I am going to post on diyaudio as well, but that thread is more focused on complex issues.

re-reading your post I'm assuming when you say primaries for the 13k/620pf (not uf, !!!), you really mean secondaries and vice versa... if not, then that may be the problem  :o.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 3 Jun 2010, 09:34 am
AD1865 DAC Update:

I have replaced the diodes by the power supply w/ fast 1A Schottkys (thanks Dave!), swapped out half the resistors in the I/V stage for PRPS and dales and half the caps for Elna Silmic II.

Here's the deal: At this moment, I have glimpsed audio nirvana. For these few moments I know why some of us audiophiles just keep on searching, keep on striving, spinning around in what seems like circles like dervishes. Because when everything falls into place and the music opens itself to you, it is a kind of bliss.

I reached that tonight w/ this dac. I would never have thought I would. Even this weekend I was pretty set on sticking w/ the Gigawork with the tranny mod. It just had a more open and engaging sound overall even though the 1865 sounded really, really good.

After swapping out those parts tonight, it's a whole other story. I've been wondering why the Lampizator article waxed so effusive about this dac kit. I mean, I was impressed but not overly so. But now I get it. If his output stage is indeed better than the kit's, I get it.

I'm going to give it a day or two. Maybe I'm just in a mood, maybe the full moon is out. Maybe it's the new xo in my speakers or A/C cleaning stuff I've been messing with.

Right now...  :o 8) :eyebrows: :wine:


 
Title: Re: DIY DAC Kits and Easy Mods
Post by: stc4life on 3 Jun 2010, 01:29 pm
re-reading your post I'm assuming when you say primaries for the 13k/620pf (not uf, !!!), you really mean secondaries and vice versa... if not, then that may be the problem  :o.

Thanks Wushuliu.  I did mean 680pf.  I do have the filters on the primaries and secondaries switched, so I will switch those and try everything again.  I will report back.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 3 Jun 2010, 08:33 pm
Update: Gave a listen this morning and a slight grunge has crept in, probably all the new stuff settling along w/ the typical L.A. daytime dirty AC (sound is always best after 11pm here, no lie). Nevertheless the dac still shines. Here's what I'm experiencing.

Lower noise: The sucky thing about noise in gear is that you never know how much you have til it's gone. The lowered noise floor of this modified dac now allows music to approach 3 dimensionality. I have a Chesky Audio Demo Disk and at one point the narrator mentions that some vocalist should sound 'palpably real'. I always chuckle at that. What the heck does that mean? Well, now I kind of understand. Vocals now hover about a foot or so front and center. Miles Davis' trumpet sounds like it leaning towards me. And I'm not talking SACD Kind of Blue, where you'd expect that - or at least hope. I'm talking mp3 on my WDTV/hard drive.

Soundscape/stage/whatever: is much wider. Like when you go to a good movie theater like the Egyptian and they're about to show Lawrence of Arabia and the screen expands and expands and expands to glorious 2:35:1 ratio. This also means I find myself turning up the volume for certain tracks I previously would have left alone.

Transparency: Up to this point, the AD1865 has been more or less on par w/ the Gig Tranny as far as transparency, with the Gig maybe having a slight edge due to less of a roll off in the HF like the stock AD1865. Now not only have the tables turned, they've been thrown out the window. The AD1865 now excels in transparency. I have never felt closer to my music.

Tonality: This is a little tougher to gauge as of yet because I have just changed my speaker crossovers, incl. some PIO caps so it's very probable that what I am hearing as far as gauging tonality right is a mix of the DAC and the xo's. I think it's safe to say that the AD1865 has more of a relaxed tone in general, the 'natural' adjective that has been used to describe it is apt. I will eventually put the Gig back in to compare for sure, but from day 1 the AD1865 has displayed less of a 'high fidelity' sound than the the cs4398, but without loss of detail.

I have ordered more Dale resistors and Elna caps to replace as much of the rest of the I/V stage as I can. Hopefully this will improve things even more. 8)

I'm havin' fun
Title: Re: DIY DAC Kits and Easy Mods
Post by: jamesdb on 23 Jun 2010, 01:16 am
Hi Wushuliu, I am interested in the AD1865N-K DAC. What value (uF & V) were the 4 panasonic FC caps you replaced with oscons that removed the dark sound? Can you tell if it has a digital input transformer on the SPDIF input? Thanks, Jim B
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Jun 2010, 01:21 am
Hi Wushuliu, I am interested in the AD1865N-K DAC. What value (uF & V) were the 4 panasonic FC caps you replaced with oscons that removed the dark sound? Can you tell if it has a digital input transformer on the SPDIF input? Thanks, Jim B

Hi Jim: 47uf, 16(?)v. 10v and up is fine for those caps.
There is a sumlink transformer. I took that off per the Lampizator tutorial - I believe
I provided a link to that in an earlier post.
Title: USB to SPDIF converter for the AD1865N-K
Post by: jamesdb on 4 Jul 2010, 03:32 am
I noticed that the same ebay seller of the AD1865N-K DAC also sells 2 USB to SPDIF converter modules. Through other google searches and ebay searches I found a number of other plug-and-play converters ranging from about $20 to $100 or more. Another option to removing the digital input transformer is to replace it with a higher quality one. Several posts recommended Newava Technology Inc S22083 at Digikey, a Lundahl amorphous core, and an Audio Note one with nickel core and copper or optional silver wiring, ranging from $9 to $99.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jamesdb on 16 Jul 2010, 09:28 pm
Wushuliu, reading your posts and the Lampizator article on the AD1865N-K DAC inspired me to buy one. It just arrived (pretty fast and packed very well) and I have a couple of questions since no instructions came with this other than the schematics.
On the power toroid which has dual primaries, the two red primaries should connect together for HOT and the two black primaries should connect together for NEUTRAL. Did you connect the single green primary to the safety ground coming in at the IEC? Did you make any other ground connections? It looks like the 2-terminal blue connector +5V & GND on the side by the DAC chip is not used, is that correct? I was not sure if that is for Toslink connections or not. And next to that are 2 connection points labeled G and ER , did you leave those unconnected as well? The Lampizator photos don't seem to show them in use.
I also tried to identify the caps you replaced that removed the dark sound, but I don't see any Panasonic FC caps on this. Were these the same six caps (silver 15uF 20V)
(http://www.audiocircle.com/image.php?id=32853)
Lampizator replaced with brown dipped tantalum 47uF 25V caps in his photo , or some others?  I noticed my board does not have the 2 large SIC-SAFCO 4700uF caps in the digital receiving power section, it has Elna For Audio there, so that is a nice free upgrade.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 16 Jul 2010, 09:55 pm
Wushuliu, reading your posts and the Lampizator article on the AD1865N-K DAC inspired me to buy one. It just arrived (pretty fast and packed very well) and I have a couple of questions since no instructions came with this other than the schematics.
On the power toroid which has dual primaries, the two red primaries should connect together for HOT and the two black primaries should connect together for NEUTRAL. Did you connect the single green primary to the safety ground coming in at the IEC? Did you make any other ground connections? It looks like the 2-terminal blue connector +5V & GND on the side by the DAC chip is not used, is that correct? I was not sure if that is for Toslink connections or not. And next to that are 2 connection points labeled G and ER , did you leave those unconnected as well? The Lampizator photos don't seem to show them in use.
I also tried to identify the caps you replaced that removed the dark sound, but I don't see any Panasonic FC caps on this. Were these the same six caps (silver 15uF 20V)
(http://www.audiocircle.com/image.php?id=32853)
Lampizator replaced with brown dipped tantalum 47uF 25V caps in his photo , or some others?  I noticed my board does not have the 2 large SIC-SAFCO 4700uF caps in the digital receiving power section, it has Elna For Audio there, so that is a nice free upgrade.

Hi James, my dac was in a temp wood enclosure up until recently so did not wire the ground, but that's probably a good idea.

for 120V, yes wire black together for neutral, red for line.

Don't know about that +5v and G/ER. That is a good question about the toslink. Maybe ask the seller? He's pretty responsive. He sells a separate multi-input toslink/coax/usb/bnc module too which would be perfect for that +5v btw if thats the case.

The silver caps removed are the ones replaced by the tantalums. I used Oscons instead per Dbe's recommendation and they work wonderfully.

You will also want to replace some of the output resistors in the jfet stage right by the L/R output.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 21 Jul 2010, 12:39 am
Hm. $2500 AD1865-based DAC. :o

http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm (http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm)

If you enlarge the interior photos, that board suuure does look familiar! :eyebrows:



Title: Re: DIY DAC Kits and Easy Mods
Post by: etcarroll on 21 Jul 2010, 01:19 am
25 hundred, and its backordered. I may have to do this project after my SACD project.

What kind of enclosure are people using for these?

Gene

Hm. $2500 AD1865-based DAC. :o

http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm (http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm)

If you enlarge the interior photos, that board suuure does look familiar! :eyebrows:
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 21 Jul 2010, 04:27 am
25 hundred, and its backordered. I may have to do this project after my SACD project.

What kind of enclosure are people using for these?

Gene

I use an Antek 12*12*3 gold alodine.

(http://www.audiocircle.com/image.php?id=32976)

Title: Re: DIY DAC Kits and Easy Mods
Post by: jamesdb on 21 Jul 2010, 06:45 pm
Sure does look familiar. Some of the capacitors they replaced with OSCON SEPC caps on the stock board went into positions where the stock caps were 20V and some maybe 25V, however the data sheets for the OSCON SEPC series shows a max rating of only 16V. Wonder if they will last long, unless the stock caps are over-rated to begin with. Wow, they also sell "quantum purified" digital cables.
Title: Re: DIY DAC Kits and Easy Mods
Post by: srb on 21 Jul 2010, 07:29 pm
Hm. $2500 AD1865-based DAC. :o
http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm (http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm)
If you enlarge the interior photos, that board suuure does look familiar! :eyebrows:

Every part would have to be "quantum purified", kissed by a virgin and blessed by a priest, and even then, $500 max.  Of course it probably would have synergy with your $3500 Lexicon/Oppo Blu-ray player.
 
Steve
Title: Re: DIY DAC Kits and Easy Mods
Post by: eclein on 21 Jul 2010, 07:31 pm

Every part would have to be "quantum purified", kissed by a virgin and blessed by a priest, and even then, $500 max.
 
Steve
Double quantum purified :dance:
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 21 Jul 2010, 08:55 pm
Sure does look familiar. Some of the capacitors they replaced with OSCON SEPC caps on the stock board went into positions where the stock caps were 20V and some maybe 25V, however the data sheets for the OSCON SEPC series shows a max rating of only 16V. Wonder if they will last long, unless the stock caps are over-rated to begin with. Wow, they also sell "quantum purified" digital cables.

I believe the stock caps are rated higher than the supplied voltage, yes. Assuming you're talking about the Jfet I/V stage, I believe it gets around 15v or something like that.

Apparently the Mojo Audio mods include major changes to PS, including supplying 40k uf. Can that much extra power be of benefit for a DAC?

I'm not gonna bash the guy for charging that much though. We all gotta eat. Just glad I'm handy with the iron!
Title: Re: DIY DAC Kits and Easy Mods
Post by: srb on 21 Jul 2010, 09:29 pm
Apparently the Mojo Audio mods include major changes to PS, including supplying 40k uf. Can that much extra power be of benefit for a DAC?

I've often wondered how robust a power supply needs to be for a DAC.  I don't know if it's a numbers game or not, but Audio-gd uses > 50,000 uF capacitance in their DACs and Wyred 4 Sound use 88,000 uF in their DAC1/DAC2.
 
I'm guessing that the DAC and receiver chips are very sensitive to DC ripple and can benefit from the large capacitance for smoothing as opposed to needing it for energy reserve.
 
Steve
Title: Re: DIY DAC Kits and Easy Mods
Post by: SET Man on 21 Jul 2010, 10:31 pm
Hm. $2500 AD1865-based DAC. :o

http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm (http://www.mojo-audio.com/AD1865NOS-D-A-Converter-AD1865NOS.htm)

If you enlarge the interior photos, that board suuure does look familiar! :eyebrows:

Hey!

   Wow! The chassis must have cost a lot :o Well, at least there are some improvements and upgrades... unlikely the Lexicon relabeled Oppo :roll:

Take care,
Buddy :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 9 Aug 2010, 07:31 pm

I've often wondered how robust a power supply needs to be for a DAC.  I don't know if it's a numbers game or not, but Audio-gd uses > 50,000 uF capacitance in their DACs and Wyred 4 Sound use 88,000 uF in their DAC1/DAC2.
 
I'm guessing that the DAC and receiver chips are very sensitive to DC ripple and can benefit from the large capacitance for smoothing as opposed to needing it for energy reserve.
 
Steve

Well for kicks I swapped out the 4700uf Nichicon Gold Tunes from the AD1865 DAC and replaced them w/ some 15000uf and 18000uf caps. There was a noticeable improvement in sound quality.

What i want to know is if it is possible to add something like a shunt regulated PS *before* the DAC, or would I need to bypass the regulators that are already on board?

Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 13 Aug 2010, 03:39 pm
Plan to embrace the AD1865K project in the next few months.  Based on the read, I'd need the following items to make a stock DAC work:

- Power Switch (DPDT) (Do I need a fuse?)
- RCA jacks for output
- Do I need a jacket for Coaxial?  Is that the same as RCA jack?  Did it come with the kit?
- Some wires.
- LEDs - can I wire LED to the board so I know the machine is on?

I plan to use my old pioneer universal dvd player as the transport with a coaxial out to the DAC for two channel music.  I might add a USB to coaxial converter later if I see the improvement vs. the old pioneer player.

I will put these on a MDF board first.  Might add a metal enclosure if I like it. ;)

Did I miss anything?
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 13 Aug 2010, 08:44 pm
Plan to embrace the AD1865K project in the next few months.  Based on the read, I'd need the following items to make a stock DAC work:

- Power Switch (DPDT) (Do I need a fuse?)
- RCA jacks for output
- Do I need a jacket for Coaxial?  Is that the same as RCA jack?  Did it come with the kit?
- Some wires.
- LEDs - can I wire LED to the board so I know the machine is on?

I plan to use my old pioneer universal dvd player as the transport with a coaxial out to the DAC for two channel music.  I might add a USB to coaxial converter later if I see the improvement vs. the old pioneer player.

I will put these on a MDF board first.  Might add a metal enclosure if I like it. ;)

Did I miss anything?

A fuse is always a good idea.
A jacket? You can use an RCA jack for the coaxial or if you want to be
precise about the impedance there are RCA jacks specifically for spdif. You
can find one at VHAudio for instance. Doesn't come w/ the kit.
The board has an led. You will have to replace it and use desired length wire
for chassis mounting.
Title: Re: DIY DAC Kits and Easy Mods
Post by: waltsok on 13 Aug 2010, 09:22 pm
I want to do the ad1865k shortly. I have never had a dac before but I do know I will also need some kind of source. What type of source or transport will i need to play cd's. Will a blu ray have appropriate out? Obviously I am new to this Thanks
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 13 Aug 2010, 10:34 pm
I want to do the ad1865k shortly. I have never had a dac before but I do know I will also need some kind of source. What type of source or transport will i need to play cd's. Will a blu ray have appropriate out? Obviously I am new to this Thanks

I learned this not too long ago.  :)

As long as the machine has a Coaxial output, it should be OK.  That's what I plan to do with my dvd player.  I also plan to add a USB to SPDIF converter to play all my computer file based music.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 13 Aug 2010, 10:57 pm
I want to do the ad1865k shortly. I have never had a dac before but I do know I will also need some kind of source. What type of source or transport will i need to play cd's. Will a blu ray have appropriate out? Obviously I am new to this Thanks

If you've never had a dac maybe you should take a listen to some retail ones before jumping into the ad1865 kit. At the very least try out some OverSampling vs. Non-OverSampling dacs. There are so many choices and the differences between OS and NOS are worth exploring before expending time and energy into a kit. Just a thought.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 13 Aug 2010, 11:08 pm
Another option that I wish existed before I bought my dac is this:

http://quanghao.com/product.php?id_product=9

It's an AD1865 board incorporating the Salas (of diyaudio) shunt-reglated power supply. The DAC circuit should be similar to the rainbow as they are both based on Andrea Ciuffoli's design. The Salas PS gets kudos and is guaranteed to be far far better than the rainbow design. And you dictate the parts quality, so end result will be in your hands.

For the IV stage, a tube-based design is also offered on that site - but another option to go easier on the wallet is rainbow's tube IV stage:

http://cgi.ebay.com/DAC-I-V-conversion-module-SRPP-tube-module-/320572208796?pt=LH_DefaultDomain_0

I'm trying to not to give in to temptation with trying this out but the chance to control all the parts myself and use Salas' PS is almost too much...



(http://www.audiocircle.com/image.php?id=33940)


(http://www.audiocircle.com/image.php?id=33941)
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 13 Aug 2010, 11:27 pm
I looked at this one and I'd really love to build one.  But, but, but, it's not for beginners and the cost will be higher I guess...  Not really know how to manage it.  There are many interests in DAC End but very few build thread that I can locate...

For example, the kit (http://quanghao.com/product.php?id_product=1) is $350.  Does it come with Salas? 

Another option that I wish existed before I bought my dac is this:


Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 13 Aug 2010, 11:37 pm
I looked at this one and I'd really love to build one.  But, but, but, it's not for beginners and the cost will be higher I guess...  Not really know how to manage it.  There are many interests in DAC End but very few build thread that I can locate...

For example, the kit (http://quanghao.com/product.php?id_product=1) is $350.  Does it come with Salas?

No, not for beginners. The completed board you linked is the same board, so yes it's the Salas PS.

Should not be too expensive though w/ the raindrop IV instead of the quanghao tube version. Probably $300 or less.

For anyone comfortable with a soldering iron, though, I think it's a great deal.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 14 Aug 2010, 12:08 am
$300 or less?  I thought the kit costs $350.  Do you mean that buying the PCB and BOM yourself out?  I haven't tried that yet but $300 or less I am a bit comfortable with.  Do I still need a two stage Transformer for the DAC End?

No, not for beginners. The completed board you linked is the same board, so yes it's the Salas PS.

Should not be too expensive though w/ the rainbow IV instead of the quanghao tube version. Probably $300 or less.

For anyone comfortable with a soldering iron, though, I think it's a great deal.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Aug 2010, 12:39 am
$300 or less?  I thought the kit costs $350.  Do you mean that buying the PCB and BOM yourself out?  I haven't tried that yet but $300 or less I am a bit comfortable with.  Do I still need a two stage Transformer for the DAC End?

Yes, just buying the PCB and getting the parts yourself. Don't quote me on that as I have not actually calculated the BOM, just guesstimating.

No, you're transformer needs may be more complicated, depending on what you choose for the IV stage.

In your case, unless you're really up for it, I would stick with the rainbow kit... argh, i mean raindrop.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 14 Aug 2010, 12:45 am
Nothing compares to BOM yourself. 

Here is the BOM:

http://www.diyaudio.com/forums/quanghao-audio-design/169318-first-run-dac-end-support-2.html#post2230137



Yes, just buying the PCB and getting the parts yourself. Don't quote me on that as I have not actually calculated the BOM, just guesstimating.

No, you're transformer needs may be more complicated, depending on what you choose for the IV stage.

In your case, unless you're really up for it, I would stick with the rainbow kit... argh, i mean raindrop.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 23 Sep 2010, 09:19 pm
Hello!

Thanks for this awesome thread!!

I have some Q regarding your, in general good, description of mods;

You say;
Quote
I have just replaced the Panasonic FCs in the AD1865 DAC w/ Os-cons, and clearly it's what I should have done in the first place; the 'dark' sound is all gone and what I am hearing now is really, really good.

Q1: Which ones are the Panasonic FCs? Is it the ones that Lampizator describes as "Silver caps"? ie C12, C5, C8, C10 and two C14?

You say;
Quote
I have replaced the diodes by the power supply w/ fast 1A Schottkys

Q2: Did you change all 16 of them? Which Shottky is it, the one with 25ns recovery time?

You say;
Quote
swapped out half the resistors in the I/V stage for PRPS and dales and half the caps for Elna Silmic II.

Q3: Okey, you really should elaborate that. Which ones did you swap with which ones? I can't find anything about "PRPS", so please elaborate, also tell me where to find them.

Q4: I bought a tube I/V-stage from raindrop-hui - any wisdom to add about it? Herer it is: Ebay Link (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320582548575&ssPageName=STRK:MEWNX:IT#ht_1923wt_1137)

Q5: Someone talked about LM317 regulators, I can't find any on my board. Only "B1020A" and "LT1084" and some unreadable! Did I get a different pieace?

Q6: Can you tell me how this is bridged? It looks as if 1 is connected to 2, and 3 is connected to 4 in this pic...
(http://iloapp.millebo.se/data/_gallery//public/3/1285275498_resized.jpg)

Here is a pic of my tube-stage;
(http://iloapp.millebo.se/data/_gallery//public/3/1285275322_resized.jpg)


Best Regards, Mattias
Sweden
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 23 Sep 2010, 10:11 pm
Hi Mattias.

1. I used the FCs to replace the silver caps (see post 90). Then I replaced the FCs w/ the Os-cons.

2. I replaced all Schottkys with On-Semi MUR120.

3. Most important resistors to replace are the 100 ohm output resistors by the output caps, just before the L/R output. If you want specifics then PM me or wait a few days and I will try and put up a pic indicating which resistors. PRP resistors are available from Partsconnexion and Hndme.com, but you can use whatever type you prefer.

4. Hm, don't know much about the tube design.

5. ? which post talks about the 317? Are you sure that is not in reference to the other
DAC, the Gigawork?

6. 1 is not connected to 2. I am also pretty sure 3 is not connected to 4. Just
a trick of the light in the photo.


w



Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 24 Sep 2010, 06:01 am
Thanks for very quick reply!
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 26 Sep 2010, 07:52 am
Hey!

    I have this DAC in my system right now. Bought from this seller, great seller by the way. :D

    This DAC use 4 TDA1543 DAC chips running in paralleled. The output come directly off those chips. There is no opamp or buffer after the DAC chips. Simple! I like it.

  The DAC uses lot of good quality component despite the price. Still I only did 2 upgrades to it. 1. Changed diodes to Schottky type 2. Changed the output caps (22uf) to Russian K73-16 22uf 63V with Jensen PIO Copper as by pass caps.

     Definitely the output cap upgrade made the biggest improvement. The stock caps sounds horrible. But I know NOS DAC so that was the first thing I looked at to upgrade.

    So far a great NOS DAC. But not for everyone. It won't do detail especially in the high like 24/96+ DAC. But I'm a fan of NOS DAC of which I feel sound more analog playing Red Book CD :D I found most 24/96+ DAC sound unease especially in the high that sometime can sound hyper unnatural. Of course they are some exception of good 24/96+ DACs out there.

    Anyway, I will take some pictures and post them here soon.

Take care,
Buddy :thumb:

Thinking I may give this a shot for the heck of it. It's so cute!
Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 29 Sep 2010, 01:22 pm
Another option that I wish existed before I bought my dac is this:

http://quanghao.com/product.php?id_product=9

It's an AD1865 board incorporating the Salas (of diyaudio) shunt-reglated power supply. The DAC circuit should be similar to the rainbow as they are both based on Andrea Ciuffoli's design. The Salas PS gets kudos and is guaranteed to be far far better than the rainbow design. And you dictate the parts quality, so end result will be in your hands.

For the IV stage, a tube-based design is also offered on that site - but another option to go easier on the wallet is rainbow's tube IV stage:

http://cgi.ebay.com/DAC-I-V-conversion-module-SRPP-tube-module-/320572208796?pt=LH_DefaultDomain_0

I'm trying to not to give in to temptation with trying this out but the chance to control all the parts myself and use Salas' PS is almost too much...



(http://www.audiocircle.com/image.php?id=33940)


(http://www.audiocircle.com/image.php?id=33941)

How about the new I/V converter on the Pass DIY site?

russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 29 Sep 2010, 07:48 pm
I'm keeping my eye out for PCBs to get made for it for sure...
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 6 Oct 2010, 09:57 pm
Quick update on the raindrop AD1865 DAC: I was taking a look under the hood earlier this week, thinking I should add some more Oscons to the PS regulator area (which is recommended in Andrea's original design) and thought while I'm poking around, maybe I ought to just bypass the jfet output stage and just use 2 resistors by passed with a small value cap (.0068uf) for a passive I/V. Andrea (Ciuffoli) mentioned that this method gave the best sound but the voltage was too low to drive an amp, so I never gave it a shot. But after a ridiculous amount of googling and reading the Analog Devices pdf it turns out that you can go use values as high as 1.5k for the resistors and several people were using just passive i/v with success. So with a fresh stock of Cardas quad and more curiosity than smarts, I used 220 ohms  for the i/v (note, the outputs go to my DCB1 buffer, and then to my amp); the nice thing about the raindrop board is that there are outputs next to the dac for just this purpose.

I was pleasantly surprised to find that I could drive my amp loud enough for my preferred low to moderate listening volume. Not only that, but it sounds good, I mean real good. I think I'm really hearing the true signature of the AD1865. Not quite syrupy warm and not quite the crystalline cs4398/gigawork, etc. Real neutral. With the jfet output stage out of the way, there's more of everything. I'll spare the adjectives - it just sounds better, much better. toe-tapping better. Down side is at 220 ohms you can't crank the music. Even with 1k, although I get more than enough volume for my needs - possibly at the expense of increased, but not necessarily audible distortion. But then I have the DCB1 which has zero gain, so this is to be expected. I'm sure a tube stage after the passive I/V would sound great, but for right now I am more than satisfied.  8)
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Oct 2010, 03:54 am
Well I broke down and got one of these guys today. It's a new offering from Raindrop and is exactly what I've been looking for in the TDA series to try out (I'm currently listening to the little Muse, which I've written about in Cheap and Cheerful): 1541, NOS, passive output, decent PS, and no frills. Straight, no chaser. I'll for sure put in new bypass caps by the chip. It takes USB, BNC, optical and I2S.

All these  DAC flirtations may seem impulsive, but I think this is a 'golden age' of sorts for diy audio and these kinds of kits/boards don't have that long of a shelf life. For a fraction of what I would pay retail I can decide for myself what DAC 'sound' appeals most: upsampling/OS like the gigawork, straight OS like the TDA, or something in between like the AD1865?.. And you can't beat the price ($110 shipped). My only worry is that the TDA chip may be fake. Should only take minutes to set up, aside from the usual enclosure headaches.


(http://www.audiocircle.com/image.php?id=37066)


Title: Re: DIY DAC Kits and Easy Mods
Post by: JohnR on 14 Oct 2010, 05:06 am
Wow, you're really going for it  :D  :thumb: The price on that one has come down, if I remember. I think I saw it a while ago, don't remember it being that cheap.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 14 Oct 2010, 05:03 pm
So my AD1865 hasn't arrived yet and you have a new toy, oh, no, two new toys.  :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 18 Oct 2010, 09:38 pm
My AD1865K arrived today.  I don't have wire instructions on the Transformer.  For the 115V x 2, I have four red wires and one yellow wire.  How should I wire them?  Which one is ground (yellow?)  US uses 110V, so I don't need to tap any wires together, correct?

The other side of transformer has four sets of wires marked as 2 18Vs and 2 9Vs.  For example, brown-brown 9v, I should connect two browns to one of the power at the board, doesn't matter which brown to + or -, correct?


So my AD1865 hasn't arrived yet and you have a new toy, oh, no, two new toys.  :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Oct 2010, 09:47 pm
My AD1865K arrived today.  I don't have wire instructions on the Transformer.  For the 115V x 2, I have four red wires and one yellow wire.  How should I wire them?  Which one is ground (yellow?)  US uses 110V, so I don't need to tap any wires together, correct?

The other side of transformer has four sets of wires marked as 2 18Vs and 2 9Vs.  For example, brown-brown 9v, I should connect two browns to one of the power at the board, doesn't matter which brown to + or -, correct?

4 red wires?  A picture or a drawing would be helpful.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 18 Oct 2010, 10:21 pm

(http://www.audiocircle.com/image.php?id=37318)

There you go...  There are four red wires and one yellow wire on the Primary 115V x 2, red, red.  My guess is to make 115v, the first and the third wires will go together and the second and fourth wires will go together, but this is just my guess.  Which one will be hot and which one will be neutral?  The yellow wire should be the ground.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Oct 2010, 10:39 pm

There you go...  There are four red wires and one yellow wire on the Primary 115V x 2, red, red.  My guess is to make 115v, the first and the third wires will go together and the second and fourth wires will go together, but this is just my guess.  Which one will be hot and which one will be neutral?  The yellow wire should be the ground.

I'm not sure it matters which side is hot or neutral, but you should contact Raindrop re: wiring to be on the safe side. I wouldn't take chances. He should have at least provided a diagram.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 18 Oct 2010, 10:49 pm
I'm not sure it matters which side is hot or neutral, but you should contact Raindrop re: wiring to be on the safe side. I wouldn't take chances. He should have at least provided a diagram.

Yes, I sent an email.  I don't want to take chance either.  Also, a regular RCA jack will do for the coaxial input, right?
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Oct 2010, 10:59 pm
Yes, I sent an email.  I don't want to take chance either.  Also, a regular RCA jack will do for the coaxial input, right?

Yes, a regular jack will do.
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 18 Oct 2010, 11:07 pm
Yes, a regular jack will do.

The six capacitors on the Dac board says 22uf/16v.  There are "seven" similar caps instead of six. 

1. Should I replace seven of them?

2. Using 47uf/16v instead of 22uf/16v?

Thx!
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 18 Oct 2010, 11:42 pm
Yes
Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 27 Oct 2010, 02:38 am
So I am in love with the AD1865.  I haven't done anything yet but it is good.  Thanks wushuliu ... 

Yes
Title: Re: DIY DAC Kits and Easy Mods
Post by: Nickel on 4 Nov 2010, 08:32 am
Hi Wushuliu

When you did the Lampo mod on the 1865 , what was the analogue output in mw?
Mine's around 6, which is too high - any idea what's wrong?

Cheers

Nick

Title: Re: DIY DAC Kits and Easy Mods
Post by: parodielin on 4 Nov 2010, 09:19 pm
I received seven 47uf/35V Elna Cerafine today.  These are polared.  How do I know which side is positive and which side is negative?

Duh...  I guess when I removed the cap, I'll know.... hate to answer my own questions. ;)  I will report back on these caps.  The sound is very good stock and was wondering what can be improved...

The six capacitors on the Dac board says 22uf/16v.  There are "seven" similar caps instead of six. 

1. Should I replace seven of them?

2. Using 47uf/16v instead of 22uf/16v?

Thx!
Title: It's WORKING ...
Post by: parodielin on 10 Nov 2010, 02:57 am
I finally concurred the soldering/desoldering w/ lots of help from wushuliu.  I upgraded seven oscons and four 10000uf PS caps.  It is really really good.  I re-listened most of my music in a two sets of my DIY speakers.  It is so smooth and transparent.
 
(http://www.audiocircle.com/image.php?id=38381)

I did not do the digital bypass yet.  That takes some courage...  :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 14 Nov 2010, 03:58 pm
Where are you guys finding this DAC?  The older link aren't bringing it up on ebay.

Russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Nov 2010, 05:47 pm
Where are you guys finding this DAC?  The older link aren't bringing it up on ebay.

Russellc

It will come up under a search for AD1865 on ebay

http://cgi.ebay.com/DAC-AD1865-AD1865N-K-NOS-1-0-NOS-/320616005653?pt=LH_DefaultDomain_0&hash=item4aa6340015#ht_2469wt_1135

Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 14 Nov 2010, 06:44 pm
It will come up under a search for AD1865 on ebay

http://cgi.ebay.com/DAC-AD1865-AD1865N-K-NOS-1-0-NOS-/320616005653?pt=LH_DefaultDomain_0&hash=item4aa6340015#ht_2469wt_1135

OK, found it.  Now what other do dads do I need to order to replicate your efforts?

Russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 15 Nov 2010, 10:33 pm
Hi Russell. The mods for this board are based on Lukasz' article. If there's a single recommended mod I would say it's replacing the dac bypass caps w/ vishay/oscon. Replacing output caps in the jfet stage w/ film caps is another good start. After that, it's really about how far down the rabbit hole you want to go.

http://www.lampizator.eu/LAMPIZATOR/REFERENCES/NOS-DAC_AD1865/ad1865.html  (http://www.lampizator.eu/LAMPIZATOR/REFERENCES/NOS-DAC_AD1865/ad1865.html)
Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 16 Nov 2010, 02:09 pm
Thanks again for the info...

Russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: walkern on 16 Nov 2010, 05:55 pm
If you are a little worried about taking on this project because you lack the necessary soldering or technical expertise (as is the case with me) there is a guy named Ted Wilson (met him at DIY Audio) who is doing complete Lampucera DACs (listed on ebay) http://cgi.ebay.com/Lampucera-Mod-Complete-DAC-CS4397-CS4398-24-96-OS-CON-/190450775270?pt=LH_DefaultDomain_0&hash=item2c57c034e6#ht_4068wt_1026 (http://cgi.ebay.com/Lampucera-Mod-Complete-DAC-CS4397-CS4398-24-96-OS-CON-/190450775270?pt=LH_DefaultDomain_0&hash=item2c57c034e6#ht_4068wt_1026)

His charge for the whole set up in a cool looking cigar box seems quite reasonable to me... and the one I bought from him sounds terrific.  I can't compare it to others here, so I'm not sure where it stands other than to say that it easily bested my previous (but 2X more expensive) NOS DAC.

Neil
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 22 Nov 2010, 07:44 pm
Hello again!

I'm struggeling with my I/V tube-stage.

As the pic below describes, there are many different caps and resistors. All of them in this pic is connected to the signal path.

1. What would you recommend to swap them for? The small, brownish electrolytic caps is staggering 280µF, I don't think they are very high quality ie. Could it be OK to put dual K73-16 in serie instead of one of these caps? That means they only be a 44µF instead of 280µF?

(http://iloapp.millebo.se/data/_gallery//public/3/1290454341_resized.jpg?width=1045&height=784)


2. The big electrolytic caps buffering the voltage regulators, they vary from 2200µF to 4700µF. I don't like them being different, doing the same. What should I change them for? More F?

(http://iloapp.millebo.se/data/_gallery//public/3/1290454429_resized.jpg?width=1045&height=784)


3. The tube stage has a capacitor of the brand "Mallory", anyone heard of it ever before? Good/Anus?

4. The cheramic caps are different (Some MKP and some MKS), when changing them, should I aim for the same type/F? Which type/brand?

(http://iloapp.millebo.se/data/_gallery//public/3/1290454403_resized.jpg?width=1045&height=784)


5.  The resistors in the tube amp look standard (cheap), in my other tube amp there are wire wounded resistors used, should I aim for the same type here? Some like carbon film resistors - ideas?
Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 26 Nov 2010, 11:40 pm
Yes
Are these the OS-cons you speak of?  I found some on that auction site, which type are being used here?

russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 27 Nov 2010, 12:35 am
47uf vishay organic polymer caps from Digi-Key or mouser 10v or greater.OP equals oscon.
Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 27 Nov 2010, 11:11 pm
47uf vishay organic polymer caps from Digi-Key or mouser 10v or greater.OP equals oscon.

I see, and thanks again.  I ve been looking for a DAC and this certainly seems reasonable for the quality of result.  What are you using for a transport?

Russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 28 Nov 2010, 12:08 am
For transport I am using my computer with USB to teralink x2 spdif converter and USB isolator.
Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 28 Nov 2010, 05:07 am
For transport I am using my computer with USB to teralink x2 spdif converter and USB isolator.

I'll have to google that up...I've just getting into this computer source thing and its all greek to me.  Any help on setup would be greatly appreciated.  That's whats got me looking at DACs in the first place!

Russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: Chris Adams on 14 Dec 2010, 06:22 pm
Well for kicks I swapped out the 4700uf Nichicon Gold Tunes from the AD1865 DAC and replaced them w/ some 15000uf and 18000uf caps. There was a noticeable improvement in sound quality.

Thanks for all the great info! I just ordered one of these and want to start collecting upgrade parts. What is the voltage on those stock Nichicon Gold Tunes?
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 14 Dec 2010, 06:57 pm
Quick update on the raindrop AD1865 DAC: I was taking a look under the hood earlier this week, thinking I should add some more Oscons to the PS regulator area (which is recommended in Andrea's original design) and thought while I'm poking around, maybe I ought to just bypass the jfet output stage and just use 2 resistors by passed with a small value cap (.0068uf) for a passive I/V.

Would you say that the resistor and bypass-cap enhances the sound? I'm listenig to mine directly from the AD1865 chip with good results...
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Dec 2010, 08:43 pm
Would you say that the resistor and bypass-cap enhances the sound? I'm listenig to mine directly from the AD1865 chip with good results...

Sorry I havent had a chance to respond to your PM. Did you manage to get things working?

When you say direct, you mean with the resistors as I/V, right? What value resistors are you using? Yes, different types of resistors impart a sound signature.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Dec 2010, 08:46 pm
Thanks for all the great info! I just ordered one of these and want to start collecting upgrade parts. What is the voltage on those stock Nichicon Gold Tunes?

The Gold Tunes were probably 35v. They didn't come with the board though.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 14 Dec 2010, 09:05 pm
The Gold Tunes were probably 35v. They didn't come with the board though.

Nope, no resistor at all, connected the RCA's directly from the three (the middle acting as ground for both left and right channel) predrilled soldering points in the marked ring;

(http://iloapp.millebo.se/data/_gallery//public/3/1292360475_resized.jpg)

The thing is, that it's loud. It is slightly louder than listening to my analog out from my Squeezebox Reciever...

I don't thinkt there would be any problem adding a resistor to this, since it's so loud.
Should I?

Modifry: Yes, it's working now, but when listening thru the Tube I/V-stage, it gets all distorted, maybe because it's too loud signal to amp..?
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Dec 2010, 09:29 pm
Nope, no resistor at all, connected the RCA's directly from the three (the middle acting as ground for both left and right channel) predrilled soldering points in the marked ring;

The thing is, that it's loud. It is slightly louder than listening to my analog out from my Squeezebox Reciever...

I don't thinkt there would be any problem adding a resistor to this, since it's so loud.
Should I?

Modifry: Yes, it's working now, but when listening thru the Tube I/V-stage, it gets all distorted, maybe because it's too loud signal to amp..?

You need the resistors!!! You can't just listen to it direct. The resistors are needed to convert the current to voltage (I/V). There are inputs for the resistors on either side of those outputs in front of the chip ~220-300 ohms is what most use. On the board it even says 220R.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 14 Dec 2010, 09:56 pm
You need the resistors!!! You can't just listen to it direct. The resistors are needed to convert the current to voltage (I/V). There are inputs for the resistors on either side of those outputs in front of the chip ~220-300 ohms is what most use. On the board it even says 220R.

Will do, but if I don't - what could happen?

/M
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Dec 2010, 10:12 pm
Will do, but if I don't - what could happen?

/M

Just saw you mentioned having the tube I/V stage. If you are using that you don't need the resistors then. What do you use after it? preamp? what's the gain of your amp?

EDIT: your tube I/V has a high amplification factor (mu 70) more suited for TDA1541 chips and similar. Way more gain than you need, which would explain the distortion. I am able to get loud enough (for me) volumes with no gain at all.
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 14 Dec 2010, 10:29 pm
Just saw you mentioned having the tube I/V stage. If you are using that you don't need the resistors then. What do you use after it? preamp? what's the gain of your amp?

EDIT: your tube I/V has a high amplification factor (mu 70) more suited for TDA1541 chips and similar. Way more gain than you need, which would explain the distortion. I am able to get loud enough (for me) volumes with no gain at all.

I'm using a homemade tube amplifier, I use the Squeezebox to set the volume (digital volume control), not optimal but sleak.
That could explain the distortion yes, damn I suck at theese things. Could I lower the amplification factor? Otherwise - who want's to buy a tweaked tube stage?  :wink:

My set:

(http://iloapp.millebo.se/data/_gallery//public/3/1288642946_resized.jpg?width=1046&height=784)
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 14 Dec 2010, 11:08 pm
I'm using a homemade tube amplifier, I use the Squeezebox to set the volume (digital volume control), not optimal but sleak.
That could explain the distortion yes, damn I suck at theese things. Could I lower the amplification factor? Otherwise - who want's to buy a tweaked tube stage?  :wink:

My set:


I see. You don't need the tube stage then. You can't lower it's gain. Just add the I/V resistors to the board instead.
Title: Re: DIY DAC Kits and Easy Mods
Post by: Chris Adams on 26 Dec 2010, 01:53 am
I just got my AD1865 up and running. There is some noise in the left channel. Best way I can describe it is it sounds like a noisy tube. Goes up and down with the volume. Anyone have this experience? I have an email in to Hui, but no response yet.
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 30 Dec 2010, 11:12 pm
Will do, but if I don't - what could happen?

/M

What did you end up trying w/ the dac? I see the tube stage is FS on diyaudio...
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 31 Dec 2010, 09:06 am
What did you end up trying w/ the dac? I see the tube stage is FS on diyaudio...

I soldered 240 ohm resistors temporarily and now I'm finishing the design and I will be trying different resistors for the I/V.

The 240 ohm is more than original in sound volume, but with some google'ing I found that most prefer low ohm's resistors.

What would you say? Since I don't have the sound volume problem, I'm thinking of trying resistors from 240 ohm to 1,5k ohm...

What watt would you say I need on the resistors?

/M

(http://iloapp.millebo.se/data/_gallery//public/3/1293733126_resized.jpg?width=1045&height=784)


(http://iloapp.millebo.se/data/_gallery//public/3/1293733092_resized.jpg?width=1045&height=784)

Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 31 Dec 2010, 03:44 pm

(http://iloapp.millebo.se/data/_gallery//public/3/1293808853_resized.jpg?width=1045&height=784)

Done!
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 1 Jan 2011, 09:53 am
Thoguht you'd be interested in this;

I tried out a different, "supposedly" authentic AD1865-chip. Guess what? It sounds _much_ better now!

Here is the comparison, the "supposedly real deal" closest to the camera;

(http://iloapp.millebo.se/data/_gallery//public/3/1293875324_resized.jpg?width=1045&height=784)

On the backside of the AD1865-chip that came with the DAC-kit from Raindrop_Hui I read "PHILLIPINES";

(http://iloapp.millebo.se/data/_gallery//public/3/1293875350_resized.jpg?width=1045&height=784)
Title: Re: DIY DAC Kits and Easy Mods
Post by: Chris Adams on 1 Jan 2011, 01:50 pm
Where did you get the chip?
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 1 Jan 2011, 02:32 pm
Where did you get the chip?

eBay.
Title: Re: DIY DAC Kits and Easy Mods
Post by: SET Man on 1 Jan 2011, 03:58 pm
Hey!

     jema, that is brilliant using Ikea metal bowl to cover the transfromer! :D I will keep that in mind if you don't mind :wink:

Take care,
Buddy :thumb:
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 1 Jan 2011, 04:02 pm
Hey!

     jema, that is brilliant using Ikea metal bowl to cover the transfromer! :D I will keep that in mind if you don't mind :wink:

Take care,
Buddy :thumb:

NP, and due to IKEA's lack of quality, it's really easy to drill holes in also!  :lol:
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 1 Jan 2011, 06:07 pm
eBay.

Ah. Thanks for the heads up. Can you post a link for the ebay seller? What does it say on the bottom of the 'fake' chip? Beautiful enclosure!
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 1 Jan 2011, 07:21 pm
Ah. Thanks for the heads up. Can you post a link for the ebay seller? What does it say on the bottom of the 'fake' chip? Beautiful enclosure!

Nothing, it's clean.

Sure; http://stores.ebay.co.uk/connectors-usa
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 1 Jan 2011, 07:32 pm
Nothing, it's clean.

Sure; http://stores.ebay.co.uk/connectors-usa

Oops, meant to say the 'real' chip. Good to know. They're located where I live! As for your resistor value question, I didn't hear much difference between 330R and 1.5k except for increase in volume. So if 240ohms is loud enough for you, you're okay. But then maybe with a 'real' chip this may change, so you may want to experiment to be sure.
Title: Re: DIY DAC Kits and Easy Mods
Post by: Chris Adams on 1 Jan 2011, 07:58 pm
Just snagged one of the 'real' chips. I'm curious. I also took a close look at the Sanyo caps on the Mojo dac board. I might get some and see how they work. The voltage values are lower than the ones on the Raindrop board, but still acceptable. I'm going to replace R1 and R14 with TX2575s.

Of course it will be awhile because I just sent my dac back to Hui for replacement. I think there was a bad JFET in the left channel. Didn't want to change them all to find out. :duh:
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 1 Jan 2011, 09:14 pm
As for your resistor value question, I didn't hear much difference between 330R and 1.5k except for increase in volume. So if 240ohms is loud enough for you, you're okay. But then maybe with a 'real' chip this may change, so you may want to experiment to be sure.

I google'd it a bit. Some say DAC zero by Audio Note use 300 ohm, some say 330 ohm, and one page said that DAC one uses 1kohm.
At multiple sites I've read that you need to go beyond 500 ohm to get an acceptable THD level. Whatever that means.

I ordered a set of (very cheap) resistors, just to compare the resistance. When I'll settle for one resistance, I'll try different types of resistors, as carbon composite / wire wounded / tantalum etc...

Do anyone know exactly what capacitors on the Raindraop-board that is used for power supply of the AD1865-chip? I swopped a couple, but I think more is involved and also, it's beginning to cost money. The large 470µF OS-CONS are $20 each.

(http://iloapp.millebo.se/data/_gallery//public/3/1293876231_resized.jpg?width=1045&height=784)

Have anyone tried adding a C-R-C filter to the PS?
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 2 Jan 2011, 02:13 am
I google'd it a bit. Some say DAC zero by Audio Note use 300 ohm, some say 330 ohm, and one page said that DAC one uses 1kohm.
At multiple sites I've read that you need to go beyond 500 ohm to get an acceptable THD level. Whatever that means.

I ordered a set of (very cheap) resistors, just to compare the resistance. When I'll settle for one resistance, I'll try different types of resistors, as carbon composite / wire wounded / tantalum etc...

Do anyone know exactly what capacitors on the Raindraop-board that is used for power supply of the AD1865-chip? I swopped a couple, but I think more is involved and also, it's beginning to cost money. The large 470µF OS-CONS are $20 each.

Have anyone tried adding a C-R-C filter to the PS?

Ouch $20? You could have used these (though I guess it's too late now):

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=493-3019-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=493-3019-ND)



Title: Re: DIY DAC Kits and Easy Mods
Post by: Atlplasma on 2 Jan 2011, 02:33 am
But I am sure those were not made by dwarves in the halls of mordore.  :lol:
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 2 Jan 2011, 09:12 am
But I am sure those were not made by dwarves in the halls of mordore.  :lol:

Me neither, since the dwarfes lives in Moria...  :wink:

In my research of the AD1865 I found out that several people thinks the AD-chip is more sensitive to ripple than for example the TD1514 chip...

OS-CON'S are world champions in ripple reduction.  8)
Title: Re: DIY DAC Kits and Easy Mods
Post by: jema on 3 Jan 2011, 01:54 pm
With the risk of being anoying, here comes more of what I've found (that you already may know)

This is mostly Ctrl+C/V from datasheet of AD1865;

The AD1865 typically dissipates only 225 mW, with a maximum power dissipation of 260 mW - So why are we adding 10 000µF to them? Higher capacitance, lower ripple reduction?

This figure is confirming what I red in a different forum; You need at least 500 ohm resistance to get acceptable THD-N levels. Though this is written in the datasheet; A load impedance of at least 1.5 kΩ is recommended for best THD+N performance.

(http://iloapp.millebo.se/data/_gallery//public/3/1294062199_resized.jpg)

THEN! The thing I was looking for, confirmation of AD1865 ripple tolerance; Analog Devices recommends that well regulated power supplies with less than 1% ripple be incorporated into the design of an audio system.
That would mean that the linear regulators is of great importance, as well as the capacitors.
Title: Re: DIY DAC Kits and Easy Mods
Post by: Speedskater on 3 Jan 2011, 02:54 pm
I wonder why they drew "Figure 4" upside down?  -100 should be on the bottom and -40 at the top.
Title: Re: DIY DAC Kits and Easy Mods
Post by: Nickel on 21 Jan 2011, 08:47 am
This could be the Philippines 1865 supplier, also on ebay

http://cgi.ebay.com/AD1865N-K-AD1865-18bit-Audio-DAC-upgrade-Audionote-/220541302381?pt=LH_DefaultDomain_0&hash=item335949366d

Title: Re: DIY DAC Kits and Easy Mods
Post by: Russellc on 7 Feb 2011, 02:24 pm
I see. You don't need the tube stage then. You can't lower it's gain. Just add the I/V resistors to the board instead.

I noticed you sold your "Raindrop" DAC over on DIY, what are you listening to now?

Russellc
Title: Re: DIY DAC Kits and Easy Mods
Post by: wushuliu on 7 Feb 2011, 04:48 pm
That was a different one. It was a TDA1541A DAC that I never got around to using. However, I have replaced the AD1865 kit w/ a used Audio-GD DAC19MK3. Love it. Would cost the same if not more to DIY something similar.

That was a different one. It was a TDA1541A DAC that I never got around to using. However, I have replaced the AD1865 kit w/ a used Audio-GD DAC19MK3. Love it. Would cost the same if not more to DIY something similar.
Title: Re: DIY DAC Kits and Easy Mods
Post by: lordearl on 18 Feb 2011, 10:00 pm
I also just got this AD1865 DAC from Raindrop Hui.

I have a nice 6SN7 SRPP preamplifier I'd like to use, but it is in a separate box.

Is the best thing to do to use resistors to make a passive i/v stage connected to the RCA terminals in my DAC chassis, then just run normal rca interconnects to the 6SN7 preamp?

I can't tell from the photos on the forum here where to solder the resistors (from what I can tell 300R seems to be the correct value).

Is anyone able to post a close up photo of how to install the i/v resistors?

Thanks  :icon_lol:
Title: Re: DIY DAC Kits and Easy Mods
Post by: jerkbag on 9 Mar 2011, 06:12 pm
Hi,

Thanks for the great tutorial. Simple question: how come that hand diagram of the cap / resister filter shows the R2 resistor connected on the + side, and yet in your photo it looks very much like you have R2 going to the Neg side of the RCA? R+ in the drawing should be going to center pin of RCA, no?

Thanks!


Line Output Transformer Mod

Next up is the output transformer mod. This is also fairly easy.

1) You bypass opamps altogether.

2) Minimal contact w/ the board, reducing risk of screwing something up while (de)soldering.

2) Since you don't need the opamps you won't need to use the ~ 12v -0- 12v part of the power
supply, only the ~9v-0 part (see Transformer/PS section below). So basically you can run out to Radio Shack or digikey or wherever and use a cheap 9v transformer, buy the kit w/o transformer from ebay and save money to use towards the *line output* transformers.

Next, Getting signal from Bypass caps

This is what you're going for. Here's a great basic pic from diyaudio:


(http://www.audiocircle.com/image.php?id=28135)

and a diagram (applies to both Left and Right):



(http://www.audiocircle.com/image.php?id=28137)


You will need resistors and caps for the filters. You can start with ~500ohms for R1 and 1nf
for C1 and then adjust up or down to taste. I also recommend PRP or Takman resistors. They are cheap
and I think preferable to the usual dale, etc. in this application. Or better yet, compare for yourself.

Let's get started.


You want to solder in the 4 signal wires. They will go the transformers and from the transformers to your RCAs

In the Opamp mod section I showed the 4 Bypass caps by the dac chip that were tossed. Same
applies here. However, instead of jumping them we will be drawing the audio signal.

From Left to Right the signal goes: R-/R+/L+/L-

You will only need to deal with the positive (unstriped) side of each one. Like so:


(http://www.audiocircle.com/image.php?id=28133)

I still recommend rocking the caps to break them off, thus avoiding full desoldering on the bottom side of the board. Then use tweezers to pull out the leads. Much easier and reduces iron time on the pads.

Also, the dac chip is removeable. So if you feel a little cramped during this part, gently pull up the dac chip from its sockets...

When you're done, should look like this:


(http://www.audiocircle.com/image.php?id=28134)

That's it for the board. Phew. Now you can be butterfingers all you want with the output transformers!


Which Output Transformers?

A wide bandwidth (20hz - 20khz or higher) 500/600:500/600 is a good start. The average price for a pair is ~$100 - 150. American-made Edcors, however are a budget alternative. Not a huge amount of feedback on their quality, but it's a reputable company.

Most Popular

UTC/TRW A-20

http://cgi.ebay.com/Pair-UTC-A-20-Input-Transformer-500-500-Ohm_W0QQitemZ310206172473QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item4839ba8d39

(http://www.audiocircle.com/image.php?id=28131)

Cinemag - ~$56 ea.

CMOB - 2H

http://www.cinemag.biz/output/output.html (http://www.cinemag.biz/output/output.html)

Altec 15356/A (on and off on ebay)


(http://www.audiocircle.com/image.php?id=28132)

EDCOR XSM600 - ~$13 ea.

http://www.edcorusa.com/Products/ShowProduct.aspx?ID=327 (http://www.edcorusa.com/Products/ShowProduct.aspx?ID=327)

These are just a few of the many to choose from. I also focused on options easily available to those
in the U.S.. Internationally there are Sowters, LLundahls, Monacors,etc. that are easier to find. You get the idea.

Now each transformer brand is different as far as their primaries (input) and secondaries (output to RCA). We want to follow the 5 or 600: 5 or 600 diagrams. In the UTC pic above for instance you can see the writing on the side:

Pins 1 and 6 = primary, signal from the board
      7 and 12 = secondary, signals to RCA
      3 and 4, 9 & 10 = Center Tap, you jump/connect these two w/ wire

So consult the transformer you have and if you have any questions just ask.

Now add the resistors and cap filter to the signal wires.

Just as in the diagram above.


(http://www.audiocircle.com/image.php?id=28138)


then attach, solder, etc to appropriate pins on your transformer.



(http://www.audiocircle.com/image.php?id=28140)


You can see the white output wires that are going to the RCAs. I did not take a close pic of the
1K, 1nf R-C filter but you can kind of see here. Just follow the diagram above.


(http://www.audiocircle.com/image.php?id=28141)

(http://www.audiocircle.com/image.php?id=28152)

There ya be. Not too tough was it?