DIY DAC Kits and Easy Mods

wushuliu · « **Reply #20 on:** 23 Mar 2010, 09:14 am »

thanks dave!

dBe · « **Reply #21 on:** 23 Mar 2010, 01:24 pm »

Quote from: wushuliu on 23 Mar 2010, 09:14 am

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

roscoeiii · « **Reply #22 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?

wushuliu · « **Reply #23 on:** 23 Mar 2010, 07:50 pm »

Quote from: 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?

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.

jb · « **Reply #24 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.

wushuliu · « **Reply #25 on:** 23 Mar 2010, 08:45 pm »

Quote from: 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.

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?

jb · « **Reply #26 on:** 23 Mar 2010, 09:09 pm »

Quote from: wushuliu on 23 Mar 2010, 08:45 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

wushuliu · « **Reply #27 on:** 23 Mar 2010, 09:16 pm »

Quote from: jb on 23 Mar 2010, 09:09 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.

wushuliu · « **Reply #28 on:** 23 Mar 2010, 11:26 pm »

Tutorial is under way on Page 1...

Mariusz · « **Reply #29 on:** 24 Mar 2010, 12:01 am »

Cool.

jb · « **Reply #30 on:** 24 Mar 2010, 12:43 am »

Quote from: wushuliu on 23 Mar 2010, 09:16 pm

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.

wushuliu · « **Reply #31 on:** 24 Mar 2010, 01:14 am »

Quote from: jb on 24 Mar 2010, 12:43 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.

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?

jb · « **Reply #32 on:** 24 Mar 2010, 01:48 am »

Quote from: wushuliu on 24 Mar 2010, 01:14 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.

wushuliu · « **Reply #33 on:** 24 Mar 2010, 03:03 am »

Quote from: jb on 24 Mar 2010, 01:48 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.

dBe · « **Reply #34 on:** 24 Mar 2010, 03:37 am »

Quote from: 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?

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

stc4life · « **Reply #35 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.

wushuliu · « **Reply #36 on:** 24 Mar 2010, 06:07 am »

Tutorial all done.

Just let your Soul Glo.

w

jeffjazz · « **Reply #37 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
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.

stc4life · « **Reply #38 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.

dBe · « **Reply #39 on:** 24 Mar 2010, 03:07 pm »

Quote from: wushuliu on 24 Mar 2010, 06:07 am

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!

Dave