[prog]

Why don't you measure Valab's voltage first?

 

[krisno]

I am no good with electronics

 

[Kooka]

Well, my experience on rising the voltage on the chips is the following: in a Monica3 TD1545 we raised the voltage and seemed to have a little more "punch", but then we tried lowering it till 7V ("normal" on Monica is 12V) and it worked much much better. with a much more "analogic" mood.
That does not mean that lower voltage is always better, but it means that higher is not always better too...

 

[PatOMalley]

Replaced the output caps with Blackgates STD 4.7uF + Obbligato .1uF + K40Y-9 PIO .001uF. The 4.7 BGs were already there. Just changed for foils for bypassing.

Wow. Really responded to that.
I heatshrunk the Russian PIOs as the body picks up noise.

Really dynamic now. Could be the 001uFs.
There was a little sibilance with the .1 BGs I didn't want to admit to.
All gone. Vocals are nice and humanly thick.
Better bass, too. Word is that with three caps they each allow the other to do it's job better within it's band. Who knows?
Even more analogic now.

Reused the .1uF BGs for bypassing the regulators caps.

 

[Kooka]

Pat, do you still have the "old" clock installed? No 1ppm one..?
Obbligato: great caps, on my opinion, but what kind did you use? I cannot see them there. Or did you cover them on the picture?

 

[prog]

The DAC chips' voltage on my Dec. 2008 Valab was 7.8V, I'm getting the 2009 this week (hopefully), but I think the chips' voltage remained unchanged.

The 2009 edition seems to have more free space around the tantalum output caps, I will try to fit some 10uF Mundorf MCap or Audyn QS there.

 

[PatOMalley]

Quote:

Originally Posted by Kooka /img/forum/go_quote.gif Pat, do you still have the "old" clock installed? No 1ppm one..? Obbligato: great caps, on my opinion, but what kind did you use? I cannot see them there. Or did you cover them on the picture?

I have the old clock but my understaning is that it is not in use thru the Toslink/coax. It is for USB. The clock on the DIR9001 digital receiver far exceeds the capabilities of that USB clock. In reference back to BIll's comments re jitter, using glass and the DIR9001 lowers jitter to the "taken care of" level.

The Obbligatos are previous version to the copper and gold with the blue wrapper. Full midrange sound. I put the Russian PIO caps on top of them and they have heatshink on them. They just fit. The Obbligato's and Russian PIOs are a good combination. I found you can use cheaper, in this case electrolytics, on the bottom value, 4.7, to just deliver bass. There are arguments for and against using a 3-4 cap array but each time I have tried it it worked better than I expected.

Much faster and effortless with the foils in there. I think the .001 PIO adds some air. With 3 caps like that it seems to increase headroom so that it seems like the music is delivered well within the performing capabilities; a lot of elbow room for the effort.

I also added these small feet from E-A-R.

 

[lmmo]

What are the dimensions of the Valab DAC?

Does anyone changed its casing? Can you show us some photos?

Thanks!

 

[PatOMalley]

The chassis' outer dimensions are roughly 4 3/4" x 6 1/2" x 1 1/2"

 

[lmmo]

Quote:

Originally Posted by PatOMalley /img/forum/go_quote.gif The chassis' outer dimensions are roughly 4 3/4" x 6 1/2" x 1 1/2"

Thanks!

 

[Kenobi]

Pat,

Your hot-rodded DAC has morphed into a serious piece of machinery--curious how it now sounds compared to stock. I wish I have the skills and know how to experiment like yourself, Bill and others.

Cheers,

Kenobi

 

[PatOMalley]

Thanks Kenobi,

I burned the hell out of a Cambridge 630p learning how to solder.
Before that I destroyed my Hagerman Bugle.
You gotta break a few eggs.
But I am a piker compared to some of the guys around here.

vs stock it is less hi-fi, more palpable presence.
A number of things made a nice improvement but the output caps make a lot of difference. The VALAB is a killer sound after burn-in. I was blasted. But it blooms even more when you mod it.

 

[Bill Allen]

Well the Blackgate caps on the board are still breaking in; this presents itself by the expansion and then subsequent shrinking of the soundstage. In the beginning this tide can go out for hours, these intervals shorten as the break-in process continues. I am at the seriously obnoxious point where every 15 minutes the dips and peaks repeat. This should finally equal out in the macro world in the next couple of days. But from Blackgate experience this will continue in the micro world for another couple of weeks. Oh joy. (Realize I am not continuously listening to this mess; I have a CD player on repeat).

In the interim I have started playing with output caps, originally using the 4.7uf Jupiter cap. Next I tried a Cryo treated 1.0uf Jupiter Cap. (Cyro treatment of the Beeswax Jupiter Cap transforms them into "the" best capacitors on the planet IMHO). This seriously opened up the soundstage as expected, however I also lost a lot of bass slam because the cap is too small. This brings us to the following picture. I bypassed the uncryo'd 4.7 uf with the cryo'd 1.0's. Bingo!

Picasa Web Albums - Bill - Mods

Well it may look like hell but damn does it sound good. A cryo'd Jupiter cap does not need to be bypassed. Plan is to take the Mod Dac over to the Cryo lab this weekend and cryo the entire Dac. At this point I will be able remove the 1.0 uf bypass caps.

Stay tuned.

 

[PatOMalley]

That is the motherload of bypassing.
That is one meaty output.
Did you have fun keeping that hot tip away from the wax?

One more cap at around .001uF in the array and you have the perfect cap.

I wish I had a cryo lab around the corner.

I did another bypass on output caps on my phono pre tonight using .001uF PIO, same as on the VALAB, and it sped things up both times. Did you notice that?

 

[Kooka]

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