Paradisea DAC

F-100 · « **Reply #220 on:** 13 Feb 2007, 06:33 am »

Occam,
Thanks for the info on the opamp on Ebay. I picked that one up and will give it a try on my DAC. Thank you!!!

Occam · « **Reply #221 on:** 13 Feb 2007, 02:09 pm »

F-100 - You're quite welcome. Some of the more 'objective' experts on audio boards might argue that I'm simply trying to impose the placebo effect and mass hysteria on our unsuspecting community, as the specifications of the chips being replaced aren't that materially different.....

Cordless89 has blown through his initial offering of only 6 OPA2107au so-8 dual opamps. Neither he or I had any idea as to what demand there might be for them. I asked him to offer more and he has agreed.
I've no business or financial relationship with him.

At this point, only cordless89 is offering the OPA2107au on Ebay, but the dip version, OPA2107ap, useable in other components, is relatively common and inexpensive. Simply do a search on Ebay for 'opa2107' (remember to look at the Ebay 'buy in now' also), and you should find them all.

EDIT - as of 12 noon today 2/13/07, Cordless89 has put up another 6 OPA2107au for sale on Ebay. It doesn't show up if you just search for 'opa2107', but rather, you need to search on either 'opa2107au' or 'paradisea'
http://cgi.ebay.com/OPA2107AU-Precision-Dual-Difet-Op-Amp-for-Paradisea-DAC_W0QQitemZ250084166619

shooter · « **Reply #222 on:** 14 Feb 2007, 06:38 pm »

Occam
Thanks for the heads up, I have a opa2107 on it way now, did you guy drop the voltage on the opamp as Legarem suggested?

Occam · « **Reply #223 on:** 15 Feb 2007, 05:13 am »

Shooter,

I'm not sure, but I told Mike to simply swap the opamps. Mike, please chime in.
I did so because, while proper capacitive decoupling is always a good thing, I don't like to see multiple modifications done at one time. If you change a bunch of things at one time, you really don't know what is effecting what. And I don't actually have a Paradisea so I don't know where the appropriate traces are.
Per Legarem's post, the opamp rail to rail on the Pardisea is 34volts, within the max for the OPA2107 of 36volts. This shouldn't be problematic with varying line voltages as those rails are fed off shunt? regulating tl431 s. That along with minimal load of driving a tube grid makes a straight swap reasonable. The extant OPA2604 has a maximum rail to rail rating of 48volts

If you were to swap Legarem's recommended LM4562, the 34v r-r is at the max rating for that opamp, so it would be a good idea to replace those resistors as Legarem did. And if you were to use some of the AD chips like the 8066 or 8620, lowering the rails would definitely be called for.

Please post your impressions of your opamp swap (including any capacitive ps decoupling).

Regards,
Paul

topround · « **Reply #224 on:** 15 Feb 2007, 10:42 am »

I am no electrical engineer, so most of you tech guys' conversations go over my head.
Replacing the output caps and bypassing them was a techy friends reccommendation, and it worked.
Replacing the opamp was talked about hear, and Occum actually led me in the right path regarding opamps. My uncle simply switched out the opamp and did nothing to the voltage.
Not sure if the voltage needs to be adjusted but it sounds great right out of the box as they say.
I think this dac responds well to mods, or just better internals.

shooter · « **Reply #225 on:** 15 Feb 2007, 03:05 pm »

Thanks for the response, I have already replace the output caps with great result, I will replace the op-amp next, before bypassing the power supply, I will report back.

Occam · « **Reply #226 on:** 15 Feb 2007, 03:34 pm »

Shooter,

Its certainly not my place to dictate how you implement upgrades. If you think it would benefit you to implement upgrades incrementally, thats great. But if doing it all in one fell swoop is easier and more efficient for you....

Regards,
Paul

drmike · « **Reply #227 on:** 16 Feb 2007, 01:01 am »

what caps did you use for bypassing?
thanks,
drmike

rajacat · « **Reply #228 on:** 16 Feb 2007, 01:45 am »

Quote from: drmike on 11 Feb 2007, 09:07 pm

hello again,
i have the constantine dac, has anyone done any mods to this particular model?
thanks,
drmike

I have the Constantine too. From what I understand, aside from the tube output stage, there is very little different from the Paridisea. I too wonder if some of the mods described here would be applicable to the Constantine.

Raj

topround · « **Reply #229 on:** 16 Feb 2007, 02:15 am »

I replaced my output caps with sonicap 4.0's and bypassed them with .22 sonicap platinum.
My uncle did the same mod with his paradisea, using Auricaps. They sound almost similiar but mine(sonicaps) have a little more bass and texture. I believe

Regarding the Constantine Dac, I believe since it is so similiar to the paradisea the mods would probably benefit it. But it takes the bold to go out and try these things. Be bold, give it a try, there really is no other way of finding out if it would help

Occam · « **Reply #230 on:** 16 Feb 2007, 04:30 am »

A few quick comments about the Constantine. Please realize I have neither a Pardisea or a Constantine. The suggestion of swapping the OP2107 for an OPA2604 in the Paradisea is a no brainer, assuming the rail to rail voltage is 36volts or less [which it is (+17)-(-17) = 34 ]
In my experience, everything an OPA2604/2134/2132 can do, the OPA2107 does mo betta. Its going to have a similar 'BurrBrown' sound signature, but with better resolution, more extention and cleaner.

The Constantine uses a Analog Devices AD826, and it has that stereotypical AD sound, not particularly warm as is typical of the BB chips. Its rated for a maximum of 30volts rail to rail, so if MHDT Labs has followed specifications, swaps for other non AD chips discussed here are not going to be problematic. If you substitute a OPA2107 for the AD826 you're going to get subjectively a much 'warmer' sound, and if one were to listen blind, one might guess the Constantine has a tube within. I happen to like that sound, but others might prefer the more stereotypical 'cleaner' AD sound. In that case, I'd suggest the National LM4562 which was suggested by Legarem for the Paradisea, but wouldn't raise voltage concerns in the Constantine, given the constraints of the extant AD826. I have directly compared the AD826 to the LM4562 in my own Zhaolu dac, and much prefer the later, finding it more extended and neutral, with nary a hint of grain. But the difference is not going to be as large as a swap for an OPA2107.
FWIW, I had 2 OPA2107 and a single AD826 in my Zhaolu for about two weeks. I finally decided I couldn't live with it, as it frankly put me on edge. I presently have those same 2 OPA2107 in the same positions, and a LM4562 in the position previously occupied by that AD826. Its been there for the last 2 months and I feel no motivation to change it.
This is a subjective call and YMMV.

F-100 · « **Reply #231 on:** 24 Feb 2007, 07:53 pm »

Received the OPA2107au couple days ago but not sure if I want to replace the op-amp first or go with the output caps upgrade. If I decide to do the output caps, then which caps is the best (Mundorf, Auriocap, SonicCraft, BlackGate, etc...). Too many options here... Any recommendation on which mod to do first?? Help!!!

bpape · « **Reply #232 on:** 24 Feb 2007, 08:05 pm »

If it was me, I'd do the opamp first. That should require little to no breakin and you should be able to hear the differences immediately.

Bryan

R Browne · « **Reply #233 on:** 25 Feb 2007, 07:09 pm »

Any installation tips for swapping the OPA2107au on the Paradisea board? My solder skills are minimal at best and I really need to practice on some cheap parts/board first. Can the OPA2107au be soldered to the top of the board or do I need to get to the other side? Is there a correct orientation to the OPA2107au?

Thanks.

F-100 · « **Reply #234 on:** 26 Feb 2007, 05:20 am »

Quote from: R Browne on 25 Feb 2007, 07:09 pm

Any installation tips for swapping the OPA2107au on the Paradisea board? My solder skills are minimal at best and I really need to practice on some cheap parts/board first.

Some soldering tutorial videos can be found here at http://tangentsoft.net/elec/movies/
Tutorial #3 shows you how to surface mount soldering and #4 show you how to desolder and rermove a chip (around 7 minutes into the video).

Quote

Can the OPA2107au be soldered to the top of the board or do I need to get to the other side?

It's easier to access to the op-amp by turning the DAC upside down. Remove the bottom cover and you'll see the op-amp in the middle of the circuit board.

Quote

Is there a correct orientation to the OPA2107au?

Yes, look for the divot or round dot on the chip, that is pin #1.

I haven't done my mod yet.. Still waiting for some more parts so good luck with your mod and please let us know your impression of the new op-amp.

ryno · « **Reply #235 on:** 27 Feb 2007, 04:37 am »

Thanks for the video link, very helpful.
I've got the opamp ordered.
This will be my first mod to the paradisea.
Other than the WE396A tube.
Ryan

R Browne · « **Reply #236 on:** 27 Feb 2007, 05:00 am »

Thanks for the information on installing the OPA2107au. It will be some time before I get around to it but I will post my impressions when I do. Right now I'm enjoying improvements the Bendix 2C51 brings to the Paradisea. While the WE 396a is a marked improvement over the stock GE tube, the Bendix is even better to my ears. Smooth, detailed and more transparent.

F-100 · « **Reply #237 on:** 27 Feb 2007, 05:57 am »

You're welcome!! I am glad to be of help.

Now it's my turn to ask the experts here for some help on bypass capacitors. The Paradisea DAC uses 1.5µF/250V for the output caps and I noticed people are using different values for the bypass caps (ex: .1 µF, .01 µF and .22 µF).

So which value is the best for bypass caps? Thanks.

F-100 · « **Reply #238 on:** 28 Feb 2007, 02:53 am »

Found the answer to my question.

In case if anyone interested, here is the link:

http://db.audioasylum.com/cgi/m.mpl?forum=tweaks&n=46106

F-100 · « **Reply #239 on:** 28 Feb 2007, 09:13 pm »

I'm going to replace the output caps with Mundorf Silver 1.5uF/1200VDC and then bypassed them with Mundorf Silver 0.1µF/1200VDC.
Is this good, bad or overkilled? Any feedback is appreciated.

Thanks