[Les Lammers]

I put the stock caps back in the other day and today received and installed the 2107 opamp. It is a bit warmer than the LM4562 but is still very detailed. The glare is much less objectionable now and I will see what the ERS does. I will let the opamp run in for a few days and give it a good listen. I will re-install the OIMP's and see what happens with the different opamp. Just remember that these changes may be very system dependent.

[emac]

I put the stock caps back in the other day and today received and installed the 2107 opamp. It is a bit warmer than the LM4562 but is still very detailed. The glare is much less objectionable now and I will see what the ERS does. I will let the opamp run in for a few days and give it a good listen. I will re-install the OIMP's and see what happens with the different opamp. Just remember that these changes may be very system dependent.

Glad to hear that you like the 2107.  The 2107 is a very good opamp, and seems to do the trick in these DACs.  Also, it sounds even better when it's properly decoupled and biased. 

[Les Lammers]

emac,

"Also, it sounds even better when it's properly decoupled and biased. "

How do you do the above?

I am just letting the unit run with a signal into it to let the 2107 settle in.

TIA,

Les

[emac]

emac,

"Also, it sounds even better when it's properly decoupled and biased. "

How do you do the above?

I am just letting the unit run with a signal into it to let the 2107 settle in.

TIA,

Les

The info on decoupling was posted by Legarum earlier in this thread.  He has pics, so that's probably better than me trying to explain it.  The biasing involves adding a couple of resistors to the pins of the opamp itself.  I can't remember offhand which values I used, so I'd have to look once I get home to see. 

[Les Lammers]

Thanks emac. I'll find the post.

[djdube525]

emac,

"Also, it sounds even better when it's properly decoupled and biased. "

How do you do the above?

I am just letting the unit run with a signal into it to let the 2107 settle in.

TIA,

Les

The info on decoupling was posted by Legarum earlier in this thread.  He has pics, so that's probably better than me trying to explain it.  The biasing involves adding a couple of resistors to the pins of the opamp itself.  I can't remember offhand which values I used, so I'd have to look once I get home to see. 

10kOhm I believe... right?

I haven't cracking my Paradisea lately to check... but I noticed in the parts list R16 and R17 @ 11KOhm are on the opposite side of the OpAmp... Anyone know if those are the biasing resistors (connect from output pin (fedback) to the input pin of the respective opamp.

Was just wondering... since I'm looking through the parts list... getting ready to replace the electrolytics, and the mhdt film caps...

BTW... what's the best source for Rubycons? I saw www.referenceaudiomods.com carry them... but wasn't sure if there was a better source... not like they are all that expensive anyways...

Lastly, other than EBAY... where are people getting their WE396A tubes?

EDIT: Okay... one more question. For the film cap replacements... has anyone tried using Sonicaps? I was thinking of using the GenII versions for the remaining film cap replacements (not the output caps). For the output caps I ended up using Gen I, bypassed with a Gen II.

I know Danny Ritchie seems to be pretty happy with them based on a price/performance ratio (they are pretty reasonable compared to many of the other boutique caps)... but for this application, you never know... any real world experience is appreciated.

Much Thanks!

Dave

[Les Lammers]

Dave,

I got my WE396's on ebay but after changing the caps I don't really care for them and they are getting pricey. *I* like the GE 5670 5 Star.
I think you will just have to try a few tubes to find out what you like best.

Les

[djdube525]

Quick Question... What's the thought on the Quality of Nicholson Muse caps? I was about to order some replacement caps... I cracked my Paradisea open, and I noticed a number of the caps originally speced to be Elnas were in fact Nicolsons.

I'm wondering how the would compare w/re to the Rubycons.

Opinions?
Dave

[Les Lammers]

Dave,

There are posts about changing those caps but *I* think changing the coupling caps will yield a bigger sonic improvement.

Les

[Quiet Earth]

My Constantine+ came with mostly Nichicon Muse caps. There were 3 Nichicon fine golds, and two Oscons. The rest were Muse. I think that the Muse caps are what you would consider a "good value". Very nice for the price, but not the cream of the crop. If you are considering replacing them, then you are probably looking to go beyond just a good value.

I replaced all of my electrolytics with Black Gates, and it is a clear and obvious improvement (after the three week burn in). Sure, it cost me 160 dollars with shipping, but I was mentally prepared to go beyond a good value. There are other tweaks that cost just as much, but they may not make as much of an improvement. Because of that, I consider the Black Gates worthwhile and still a good value.

There is another very inexpensive tweak that made a big difference with my DAC. It involves the two capacitors that are part of the negative feedback circuit of the op amp. I removed the two 1200pF negative feedback capacitors (Phillips Mial, blue) just to hear why they were there. Noise. So much noise that I could barely hear any music coming through all of it. It seems that the op amp has such a wide bandwidth (55MHz) that it is amplifiying all of the high frequency digital nasties that are going on next to it. This, combined with the incredible amount of gain makes for a noisy mess. (I realize that there are other reasons to have the cap there, like preventing oscillations, impedance stability, etc., but the obvious issue here is noise rejection.)

Anyway, instead of putting the Phillips caps back in, I tried some silver micas there. The closest value I had was 2200pF, so in they went. I noticed that the sound was a little more rolled off in the highs, due to the higher capacitance value. The high end still had that papery dryness. Last friday I received some smaller values of silver mica caps, so I tried the 120pF. Bingo! Highs are much more extended and the papery dryness is greatly diminished. (Also, there is zero noise, so they are doing their job.) This is an incredibly cheap tweak for those that are interested. Here's where I got them :
http://www.hndme.com/productcart/pc/viewCategories.asp?idCategory=25

I'm going to experiment with the two negative feedback resisters next week, just to see if I can get a little more dynamic range out of the op amp without driving it into compression. After that, I'm done.

Honest, I'm done . . . . . . . 

[Quiet Earth]

Dave,

There are posts about changing those caps but *I* think changing the coupling caps will yield a bigger sonic improvement.

Les

I agree. If you haven't tried this first, then that's where you should begin. The two output coupling caps.

[Gordy]

The Muse series is Nichicon's top of the line and is what many pro modifiers use to replace lesser caps, see Underwood/Parts Connexion for instance.  I'd leave them right where they are!

[drmike]

quiet earth,
what are the numbers of the two negative feedback caps that you replaced?
thanks,
drmike

[Quiet Earth]

quiet earth,
what are the numbers of the two negative feedback caps that you replaced?
thanks,
drmike

In my unit, the two feedback capacitors are C24 and C25. Keep in mind that I have the Constantine+, made early this year. Those two capacitors may not be the same number designation in the Constantine or the Paradisea. (i.e., they don't match the online BOM for the older Constantine.)

The Phillips MIAL 1200pF caps that I replaced are blue, and they are longer than they are round. They are axial leaded and they say :
 MIAL
1200J
63VL

I also relocated the 120pFsilver micas closer to the pins of the op amp (using the via holes right next to the op amp) but I don't know if that was necessary. The pins used for feedback on the LM4562 are 1 and 2 for channel A, and 6 and 7 for channel B. http://www.national.com/images/pf/LM4562/20157255.pdf

[djdube525]

Well... this is where I'm at:

- Replaced output coupling caps with 2uF Gen I Sonicaps
- Added .22uF GenII bypass caps to the above output caps
- Have the GE 5Star w/D-getters tube (came with DAC when I bought it used)
- Replaced op-amp with OPA2107
- Added ceramic and tantalum bypass caps to above op-amp
- Made RCA cables with Belden 89259 coax and Neutrik Profi connectors

Things I plan on doing (in no order):

- Replace remaining MHdT Film caps with Gen II Sonic Caps
- Replace fuse ($3 Radio Shack sounded reasonable)
- At least replace remaining Elna eletrolytics w/Rubycons (Blackgates would be nice, but pricey)
- Decide on whether to replace Nicholson Muses with Rubycons
- Make Crump/Asylum power cable (I was going to make some for my speakers, so why not)

So my big questions are...
- Thoughts on Nicholson Muse vs Rubycons?
- $3 Radisoshack or more expensive Isoclean fuse?

Opinions?

Thanks!

Dave

[Les Lammers]

I tried the Rat Shack fuses and have sme AHP fuses from Germany coming. One copper and one gold. A Furutech fuse is coming too.

I think it is worth putting a few $$ in these DAC's because they simply sound better. As far a tubes and capacitors go you just have to try a few and see what works for you. There is no best, just what sound better in your system.

[Les Lammers]

Well... this is where I'm at:

- Replaced output coupling caps with 2uF Gen I Sonicaps
- Added .22uF GenII bypass caps to the above output caps
- Have the GE 5Star w/D-getters tube (came with DAC when I bought it used)
- Replaced op-amp with OPA2107
- Added ceramic and tantalum bypass caps to above op-amp
- Made RCA cables with Belden 89259 coax and Neutrik Profi connectors

Things I plan on doing (in no order):

- Replace remaining MHdT Film caps with Gen II Sonic Caps
- Replace fuse ($3 Radio Shack sounded reasonable)
- At least replace remaining Elna eletrolytics w/Rubycons (Blackgates would be nice, but pricey)
- Decide on whether to replace Nicholson Muses with Rubycons
- Make Crump/Asylum power cable (I was going to make some for my speakers, so why not)

So my big questions are...
- Thoughts on Nicholson Muse vs Rubycons?
- $3 Radisoshack or more expensive Isoclean fuse?

Opinions?

Thanks!

Dave

Dave,

IMHO I'd go a little slow with the rest. That way you can tell which mod is doing what sonically.

Les

[Pelé]

Just wanted to add an upgradesuggestion that has not been mentioned in this thread. Referenceaudiomods.com has an OPA627 Module, Dual OPA627, 8 Pin/DIL http://www.referenceaudiomods.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=RAM&Category_Code=OPAMPS. For the time being they are out of 627's, but deliver the module with lm49710's instead. It is everything they brag about on their site, and IMO the best opampsolution.

[Les Lammers]

Are you using it in the Paradisea?

[Pelé]

Are you using it in the Paradisea?

Sorry, yes the paradisea+