Valab NOS DAC - subjective listening and modifications

[mattzack]

Hi Phill, Thanks for posting that picture showing the Obbligato's bypass caps. It looks simple enough. Did you keep any other dac since you fell in love with the Valab?
MattZack2 from Audiogon

 

[krisno]

GUYS... one last from me. Sorry for all this back and forward..

The Mundorf M-Cap supreme 4.70uf measures 36mm * 56mm ... I need two of these in the Valab to replace the output caps!

WILL two of these fit in the Valab 2009 version somehow and at same time being able to put the lid on??? .... (if not I probabably have to drill a hole in the casing but I rather not)... Is there enough space on top of the inverted dac chip board for two of those?? I don't have the DAC here you see, so I can't measure it myself..

Thanks!! I will get those, though very expensive. But never compromise.. hehe

Kris

 

[adam2434]

Is 6.3v rating enough for the output caps?

I'm looking at Black Gate NX Hi-Q 22uf 6.3v.

I calculate 7.2v peak-to-peak with the 390R IV resistor, and 6.1v peak-to-peak if I were to change to a 330R.

Maybe it's just safer to go with an N 33uf 16v.

Also, is 0.5w enough for the IV resistor? I believe so, but want to get a feel for the lowest wattage necessary.

Thanks,

Adam

 

[Bill Allen]

Adam,

when using Blackgates as output caps I recommend you use 2 per channel in whats called Super E configuration. You simply solder a pair together reversing the leads. While the Blackgate N's are supposed to be non-polar ... that's not completely true. You do double your capacitance by paralleling but the value is still in the cleavage. You are correct 6.3 volt is right on the edge but using the highest quality Blackgate NX HiQ you should be fine. IMO all these BG caps are cheap enough "in the big picture" that i suggest that you try both versions.

Also this is not the time to cheap out on resistors, I have it on first hand knowledge that the Blackgates and Caddock Tetrinox Film (USF 340 or 020) work fantastic together. I use 400 ohm and never once heard any clipping.

Even if you could find a particular recording that would momentarily clip .... who cares. It would be like listening for a click on an album or pushing you SET amp to bottom out and then saying ... ah-huh!. Look you don't buy a passive analog section, NOS, non filtered, paralleled DAC for its measured stability. You buy it for it's unparalleled sound.

Ok so now I'm on a rant .... but it's time somebody said it!

 

[Bill Allen]

Kris,

there's no way any 4.7 radial film cap is going to fit inside this case with cutting the top off, or mounting an external box like I did.

However, if money is not an object, you could go for the best of the best IMO.
DUELUND VSF "Virtual Stacked Foil" Speaker Capacitors

http://www.partsconnexion.com/t/cata...itorsFilm.html

These thin chocolate bars will "just fit" inside the case!

Bon Appetit!

 

[krisno]

Dear Bill

Always a pleasure to hear from you(and everybody else of you)...

I really wonder what difference I will here on upgrading since I am using USB input... anyways. Those Duelund are crazy stuff... and they would fit, that is nice, but they are expensive as hell. $130..

I will cut the top of then and either go for:

Mundorf Supreme 4.70uf 36mm D * 56mm L £20.07

or this combo:

Mundorf Supreme Silver/oil 0.22uf 19mm D * 39mm L £17.21
Mundorf Supreme 4.70uf 36mm D * 56mm L £20.07

This last combo is it worth the difference?? Does that silver thing bypassing offer anything to the sound that the supreme does not by itself? I need to decide and make order by tomorrow..

 

[krisno]

By the way, Bill... does bypassing really make a difference or is it placebo? Some say its actually for the worse.

I think I might settle for Claritycap sa + mundorf supreme 0.22 ..... its cheap combo and humblehifi guy recommends it..

 

[PatOMalley]

Krisno,

I have an idea for you.
Before going full bore at this and spending more money before knowing even what to expect or look for why don't you invest in a good but inexpensive .1uF foil cap and bypass the already existing cap?

Otherwise you are all over the road.

Bypassing has been used to make a poor cap better and that might be what your target should be in this case.

You could try a .1uF foil cap from Dynamicap which will set you back $14.95 each, $30 total.

Quote:

Originally Posted by krisno /img/forum/go_quote.gif By the way, Bill... does bypassing really make a difference or is it placebo? Some say its actually for the worse. I think I might settle for Claritycap sa + mundorf supreme 0.22 ..... its cheap combo and humblehifi guy recommends it..

 

[tubes]

I agree with Pat, bypassing the existing caps is easy and can make quite an improvement with the right caps. I bypassed my caps using .22uf Obbligatos, while they really made an improvement I feel they're not quite the perfect fit, quality .1uf caps will probably do the trick.

 

[Amertuollig]

My bodybuilded valab dac :

I like the Obbligato Premium capacitors (10 uF).

The I/V resistors give also their own sonic properties to the sound of the dac. Actually i am using NOS 360R resistors for which i have no details except for the tolerance (+/- 2%). More smooth, accurate and natural sound with these resistors in comparison with the 350R fim metal resistors used previously.

The wires have been replaced by Gotham shielded single strand cable and numerical shielded cable.

Very very nice sounding DAC.

 

[PatOMalley]

Amertuollig,

Nice piece of work! This little DAC's chassis is a Chevy Nova. Soup it up a little and it comes out looking like a street hot rod.

 

[krisno]

Nice work...

No guys, I don't want to spend too much time.

I have 2 choices (and as my friend taught me), solderd directly from ferrite bead to the RCA.. will that create ohm mismatching btw?

Anyways... the choices are:

Mundorf Supreme 4.70uf 36mm D * 56mm L £20.07

or combination of

ClarityCap SA 4.7uF 630V 35 x 46 £4.77
Mundorf Supreme 0.22uf 20 * 38 1.0 * 60 £7.97

.... the latter is chear by about 30%, but cost is not that much of an issue.

Any comments?

I need answer on this tonight so I can make the order. thanks again!

K

 

[r8833]

Krisno


the end of the ferrite bead actually leads to the caps. if you follow the trace on the board you will see. I soldered the other end of cap directly to the rca's bypassing the 47k smd resistors and the extra wire. I noticed it was fuller sounding ...Bill also came to the same conclusion in post #116

Rich

 

[Carlter]

Hi all

I was using bg N33uF + bg N1uF for output before have them ran over a week but still missing some highs , so last night throw in a pair of M-cap Silver Gold 0.01uF and yahooo smooth extend highs are back with some extra details i couldn't complain for more so happy now .

Hey Amertuollig u got a monster there ~ very nice

 

[krisno]

I settled on the 4.7uf Obbligato cap as output. I will not bypass it.... I hope not to spend more on this DAC.... Btw, I read in a big test that Jupiter is the worst cap they ever came across and distorted like hell.

Don't look forward to soldering in those obbligato's in that thing but..

Thanks guys!