Paradisea DAC

Quiet Earth · « **Reply #620 on:** 22 Feb 2008, 12:41 am »

Quote from: t-head on 21 Feb 2008, 06:38 pm

Would you recommend output cap switch as first mod?

I would also recommend the output caps as the first and possibly the only mod. I like paper in oil caps and I found that 0.47uF copper PIO works well for me. I suppose you could use 1.0 to get that last cycle of bass. 2.0uF seems like overkill to me. Mostly because if you are going to spend that kind of money, why not get a better 0.47 cap? There is no right or wrong here. Just a clear consensus that upgrading the quality of those two output coupling caps makes a big difference. It's a no brainer.

The reason why I say you may want to stop right there is a bit lengthy. I will post more about my power supply capacitor changes when I have a little more time. The Black Gates did make a big difference. They also highlight some of the other weaknesses in the DAC and it makes you want to dig deeper. Is that what you really want to do? Now I'm boning up on my op amp theory, negative feedback, gain, bandwidth, the I/V resistors (or lack thereof in the case of the Constantine+

), etc., etc. Do you see where all of this can lead? It can lead to rebuilding and revoicing the entire product. I'm having fun but I don't recommend it if you just want a bargain DAC that is (nearly) plug and play.

If you go back, way back into this thread, you will find that the people before us have already been through the op amp changes. Guess what many decided on? The LM4562. This is what you get in the box with a new unit. Be careful before you decide to start changing op amp flavors. Do lots of homework first. Or let it be.

I'll post a little more about the power supply changes that I made, and why I actually removed some of the bypass caps altogether when my head stops hurting . . . .

QE

t-head · « **Reply #621 on:** 22 Feb 2008, 12:58 am »

emac and QE,

Thanks for the advice...I hear ya...I don't really want to build or rebuild a DAC. Coupling Caps are all I am thinking now...I already have the LM4562...note to myself - it is about the music, stupid

- listen more, tweak less...

t

emac · « **Reply #622 on:** 22 Feb 2008, 01:43 am »

Interesting. Today, I bought some Radio Shack fuses to see if they made any changes in my Constantine. Popped out the old slow blow 300mA fuse and dropped in a fast blow 1.5A fuse (closest I could find). Immediate difference. More detail and the imaging was sharper. Unfortunately, I'm not sure just yet, but I may be recessing one area of the mids. I'm going to let it burn in a bit (do fuses even need a burn in?) and then see again.

Basically, I just wanted to see for myself if fuses make a difference, and the answer is a definite yes. I also bought slow blow fuses, and I'll get to the soon enough. Does make me wonder what Isoclean or Hi-Fi Tuning fuses would be like...

And remember to pull out the power cord if you're going to change fuses. Got a nice shock when I didn't.

Edit: A slow blow fuse worked much better than the fast blow fuse. The fast blow emphasized the highs a lot more (making the image seem sharper), which the slow blow is more balanced with the increased detail.

Brown · « **Reply #623 on:** 22 Feb 2008, 05:42 pm »

Emac be carefull with fuse type. The slow blow was choosen for a reason by the manf. I would consult with them to find out if the fast blow fuse fails what is it going to take with it? Be carefull

brown

emac · « **Reply #624 on:** 22 Feb 2008, 06:15 pm »

Quote from: Brown on 22 Feb 2008, 05:42 pm

Emac be carefull with fuse type. The slow blow was choosen for a reason by the manf. I would consult with them to find out if the fast blow fuse fails what is it going to take with it? Be carefull

brown

I emailed the designer before I started playing around with the fuses. In his reply he said that the 1A fast blow fuse offers about the same protection as the 250mA slow blow that comes w/ the DAC.

It's kind of a moot point though since I prefer the replacement slow blow fuse to the fast blow one anyway. More tonally balanced, but keeps the clarity of the fast blow type.

Les Lammers · « **Reply #625 on:** 23 Feb 2008, 03:17 pm »

Quote from: Quiet Earth on 22 Feb 2008, 12:41 am

Quote from: t-head on 21 Feb 2008, 06:38 pm
Would you recommend output cap switch as first mod?

I would also recommend the output caps as the first and possibly the only mod. I like paper in oil caps and I found that 0.47uF copper PIO works well for me. I suppose you could use 1.0 to get that last cycle of bass. 2.0uF seems like overkill to me. Mostly because if you are going to spend that kind of money, why not get a better 0.47 cap? There is no right or wrong here. Just a clear consensus that upgrading the quality of those two output coupling caps makes a big difference. It's a no brainer.

The reason why I say you may want to stop right there is a bit lengthy. I will post more about my power supply capacitor changes when I have a little more time. The Black Gates did make a big difference. They also highlight some of the other weaknesses in the DAC and it makes you want to dig deeper. Is that what you really want to do? Now I'm boning up on my op amp theory, negative feedback, gain, bandwidth, the I/V resistors (or lack thereof in the case of the Constantine+ ), etc., etc. Do you see where all of this can lead? It can lead to rebuilding and revoicing the entire product. I'm having fun but I don't recommend it if you just want a bargain DAC that is (nearly) plug and play.

If you go back, way back into this thread, you will find that the people before us have already been through the op amp changes. Guess what many decided on? The LM4562. This is what you get in the box with a new unit. Be careful before you decide to start changing op amp flavors. Do lots of homework first. Or let it be.

I'll post a little more about the power supply changes that I made, and why I actually removed some of the bypass caps altogether when my head stops hurting . . . .

QE

I agree. You can go to far and end up redisigning it into something that has no resale value. I bought it because it was a budget...sort of... NOS DAC w/USB. *I* think it sounds very good with different coupling caps and a better power cord. *I* have found that power cords have the biggest effect on digital, EMI, RFI,WTF and it does not necessarily have to be expensive.

t-head · « **Reply #626 on:** 23 Feb 2008, 03:33 pm »

Les,

Any suggestions on cords? I have a Volex and one from a laptop PS. I have a dislike for big, thick, stiff types that are awkward and tend to pull light electronics like the Paradisea off the shelf...

Richard

Les Lammers · « **Reply #627 on:** 23 Feb 2008, 04:58 pm »

Hi Richard,

Cords are a funny thing. I have never used a Volex but it looks like a good cord and may be as good as anything else. I am using a VH Audio Flavor 3 on the DAC and like it. You get a 30 day MBG from Chris. I will never buy another cord IC etc. w/o a MBG because they are so subjective. Hope this helps.

Les

t-head · « **Reply #628 on:** 23 Feb 2008, 05:12 pm »

Hi Les,

Thanks. I am using a Pulsar IC to connect the UD 10 to the Paradisea+ and am aware of Chris' products. I don't think you will find me spending big bucks on power cords, ICs, speaker cables, etc. That said, I have noticed differences...I also noticed the lack of connection to ground on the IEC connector on my DAC...

t (Richard)

Quiet Earth · « **Reply #629 on:** 23 Feb 2008, 06:25 pm »

Quote from: Quiet Earth on 22 Feb 2008, 12:41 am

.I'll post a little more about the power supply changes that I made, and why I actually removed some of the bypass caps altogether.......

After I upgraded the electrolytic power supply caps to Black Gates, I started to question the purpose of the MHDT brand bypass (decoupling?) capacitors. Two questions popped into my mind ;
1. Are we bypassing a large electrolytic? If so, why?
2. Are we decoupling a component (such as the op amp or the TDA1545, or the usb chip, etc)? If so, why the long trace to get to the decoupling cap?

As far as bypassing large electrolytics go, if you have already got a good electrolytic in the first place, then bypassing it may not be much of an improvement. A change, maybe, but an improvement, maybe not. This is probably one of those controversial issues that has no resolve. Some guys like to bypass, and then bypass the bypass capacitor. Others like the sound of just one quality cap without any bypass cap. The only way to find out which you prefer is to try for yourself. I have removed C5, C10, C21 and C22 completely from the circuit, and I prefer the sound without them.

Some of the decoupling capacitors, (those intended to shunt very high frequency noise from a component to ground) are physically far away from the IC intended to get decoupled. If you are so inclined to physically relocate the capacitor closer to the pin of the IC (and if it is possible to do so), this could help in two ways. First, you could probably get away with a smaller value of capacitance, and second, you can substitute for something better suited to the task. I replaced UC7 with a 3300pF silver mica and C13 with a 4700pF silver mica. I also relocated them closer to the IC pin that they are bypassing. Large value silver micas are only a few dollars each, and that is a reasonable upgrade to the 0.1 uF MHDT "decoupling" capacitor (or even the Radio Shack caps). I realize that the capacitance value is much lower, but try it and see if you really need all of that capacitance in the first place. I will try to decouple the op amp (via relocation) later next week. For now it has none.

Right now the only MHDT cap left in my DAC is C14, which appears to couple the S/Pdif signal into the TDA1545. I have some .01uF Obligato caps on order and I will try one of those in that location when they get here. I will also try one of the Obligatos (and relocate it closer to the pin) at C10.

I have also been studying and experimenting a little bit with the op amp. I have some resistors and more silver micas coming next friday and I will learn a little more about the feedback circuit at that time. This is turning out to be more fun than I thought it would be. I hope I am not going over the edge . . . . .

More later . . . .

tvr2500m · « **Reply #630 on:** 23 Feb 2008, 07:11 pm »

Interesting. I have the TDA1543-based Digital Dialogues, the 2.1 and 2.2. I like them a lot. Have you happened to give these a look/study?

- SJ

Quiet Earth · « **Reply #631 on:** 23 Feb 2008, 09:17 pm »

I'm sorry, I haven't looked at the Dialog closely yet. I've had my hands full with the Constantine up until now.

Here is a the latest picture of my Constantine+ : http://s7.photobucket.com/albums/y297/Quietearth/?action=view&current=capchange422108.jpg

You may notice a couple of other changes surrounding the op amp. I'll talk more about that after I get my parts next week.

Les Lammers · « **Reply #632 on:** 23 Feb 2008, 10:15 pm »

Quote from: t-head on 23 Feb 2008, 05:12 pm

Hi Les,

Thanks. I am using a Pulsar IC to connect the UD 10 to the Paradisea+ and am aware of Chris' products. I don't think you will find me spending big bucks on power cords, ICs, speaker cables, etc. That said, I have noticed differences...I also noticed the lack of connection to ground on the IEC connector on my DAC...t (Richard)

The Flavor 3 is for gear w/o a ground. I am not sure if it would make a difference to use a cord w/ a ground.

Les Lammers · « **Reply #633 on:** 24 Feb 2008, 02:10 pm »

I think I need to post this to avoid further confusion about mods to the Paradisea+. The + has a different OP amp ( NA4562) than the original Paradisea. Which, I think, was the OPA2604U. From what I read the OPA2107 is warmer sounding than the NA4562. Also, the + has a different transformer.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=260213050476&ssPageName=STRK:MEWA:IT&ih=016

Now that the OIMP V caps are settled in the sound is on the bright side of neutral with the NA4562.

Where I am going with this is that *we* should be careful making changes to units with different parts as the results will not be the same.

If the above OPA2107 is a plug and play substitute for the NA4562 *I* think I am going to get one and plug it in and give it a listen. The opamp is socketed in the +. It may be a better choice with the OIMP caps. It's cheap and easy to change..I think. Are there any tips for swapping the opamps? Removal.. tweezers? I don't want to damage it. If this does not balance things out I will put the original MHDT caps back in and/or try some other caps. How set in stone is the 2.0uf value and what will going to say a 1.0 or .47uf do?

I bought a Bendix 6385 and when I plugged it in with the original caps the sound was damn good...actually sounded better than it does now. The 6385 does not sound the same with the OIMP caps. Bright side of neutral regardless of which tube is used. GE 5 Star, 50's Raytheon, WE396A, Bendix 2C51, are all very similar. Also, it does not matter which IC, digi cable or power cord I am using. The basic bright side of neutral is still dominant

Bottom line: the OIMP caps may not be optimal for the Paradisea + with the NA4562.

I hope this makes sense. Thoughts?

t-head · « **Reply #634 on:** 24 Feb 2008, 02:20 pm »

Les,

Thanks for the post...rethinking mods...the UD10 was a definite improvement over native USB connection on P+...might just stop there...I have another 'transport' incoming next week...I2S output to coax input...I will report back...

t (Richard)

emac · « **Reply #635 on:** 24 Feb 2008, 03:46 pm »

Quote from: Les Lammers on 24 Feb 2008, 02:10 pm

Where I am going with this is that *we* should be careful making changes to units with different parts as the results will not be the same.

If the above OPA2107 is a plug and play substitute for the NA4562 *I* think I am going to get one and plug it in and give it a listen. The opamp is socketed in the +. It may be a better choice with the OIMP caps. It's cheap and easy to change..I think. Are there any tips for swapping the opamps? Removal.. tweezers? I don't want to damage it. If this does not balance things out I will put the original MHDT caps back in and/or try some other caps. How set in stone is the 2.0uf value and what will going to say a 1.0 or .47uf do?

I bought a Bendix 6385 and when I plugged it in with the original caps the sound was damn good...actually sounded better than it does now. The 6385 does not sound the same with the OIMP caps. Bright side of neutral regardless of which tube is used. GE 5 Star, 50's Raytheon, WE396A, Bendix 2C51, are all very similar. Also, it does not matter which IC, digi cable or power cord I am using. The basic bright side of neutral is still dominant

Bottom line: the OIMP caps may not be optimal for the Paradisea + with the NA4562.

I hope this makes sense. Thoughts?

You've hit on a good basic point. The parts that we're replacing were chosen because they synergize well. When we mod different parts, it could easily through off the synergy, even though the newer parts are better. Thus, the OIMP may not be optimal in your case, and you may need to try something else.

As for changing the opamp, refresh my memory, does the Paradisea + use an adapter or is the opamp directly soldered to the board. If there's an adapter, then tweezers are fine. If it's soldered to the board, then it's probably easiest to look earlier in this thread where Occam talked about how to change SOIC opamps.

Les Lammers · « **Reply #636 on:** 24 Feb 2008, 03:59 pm »

Emac,

The opamp in the + is socketed. Do you know if the 2107 is plug and play? If so, I will get one and post the results with the OIMP caps. Yes. changing parts without regard to synergy is like overspicing food.

I have no regrets about trying the OIMP caps but they may not be *right* for the +. Usually, I have found that changing coupling caps is a no brainer.

emac · « **Reply #637 on:** 24 Feb 2008, 04:14 pm »

Quote from: Les Lammers on 24 Feb 2008, 03:59 pm

Emac,

The opamp in the + is socketed. Do you know if the 2107 is plug and play? If so, I will get one and post the results with the OIMP caps. Yes. changing parts without regard to synergy is like overspicing food. I have no regrets about trying the OIMP caps but they may not be *right* for the +. Usually, I have found that changing coupling caps is a no brainer.

Just put in the 2107 and let her go. Did that myself. Makes a surprisingly large difference to the overall sound of the DAC. And make the opamp change before you do anything else because the opamp change makes a bigger difference than changing the caps.

Les Lammers · « **Reply #638 on:** 24 Feb 2008, 04:33 pm »

Thanks. I just bought one off the bay will and try it B4 I go back to the original caps. The Paradisea + may be 'just right' as built with the exception of the 'right' tube for your system and ears. What opamp was in your Constantine?

emac · « **Reply #639 on:** 24 Feb 2008, 04:42 pm »

Quote from: Les Lammers on 24 Feb 2008, 04:33 pm

Thanks. I am going to get one off the bay and try it B4 I go back to the original caps. The Paradisea + may be 'just right' as built with the exception of the 'right' tube for your system and ears.

Or the right opamp for your system and ears. I don't have enough experience w/ tube rolling to say how much of a difference it makes, but I wouldn't be surprised if opamp rolling had as much of an impact as tube rolling in this DAC.

As for the Paradisea + being 'just right' as is, you might be right that it's well balanced as is. That being said, there's still room for improvement and with some experimentation, you can find a better sounding 'just right'.