[Bill Allen]

My friend Tony had previously performed the Total Performance Mod but made the mistake of using BG coupling caps. (Yea he cheaped out) Going head to head with my TP DAC "his" Dac Bombed. The only difference being his Blackgate coupling caps.

Anyway with the help of the 20% off sale at Parts Connexion. Parts ConneXion - The authority on hi-fi DIY parts and components He Pony'ed up and installed 4.7uf Duelund VSF Copper Caps. It safe to say that the Duelund's hit the ball clear out of the park. The damn things are setting off car alarms in his neighborhood. Dogs are barking at the moon, women are dancing naked in the street. Well you get the idea ... you get what you pay for!

Do to the size of the Duelund Chocolate Bar Caps he moved the entire Valab Dac board to a new case and rewired the Analog Output Section. He reports large gains here too!

I am trying to talk him into putting up a complete mod report on this forum.

 

[Bill Allen]

First off Jupiter Caps are not vintage caps. No, not even the previous generation orange colored ones, they where all made in this century. Previous or “new series” I find Jupiter Caps the best value in High Performance Caps.

This is their website: Welcome to Jupiter Condenser Co.

I spoke with Chris Young the owner, and in response to those of us reporting huge gains cryoing his caps, all future Jupiter Caps will be factory Cryo'd. Nice! He has just finished a batch of the “new series” large value caps required for the Valab. I will try and get my hands on a pair and report back … maybe even doing a shoot-out with Tony’s Duelunds.

While one can get away with 1.0uf caps in the Valab, understand you will start to roll off bass response, however depending on your speakers or headphones this roll-off may be barely noticeable.

 

[r8833]

Rhodes54


where do buy the TexasI resistors? direct from them? ...also considering the Riedon ultra-precision Foil Resistors anybody try them @ 22.00 each


Rich

 

[rhodes54]

Quote:

Originally Posted by kevb /img/forum/go_quote.gif Hi Rhodes54, Thanks for the heads up on the undersized fuse - do you know what is the rating of the fuse is? I'll look around for a larger version with the same VA rating...

The VA rating is often written on the metal ends of the fuse.
By the way: The VA rating depends upon your AC voltage. In holland we have 230V and I oversized it right now with a 1A fuse because I didn't have anything else at hand. I guess a 250mA-500mA fuse will be enough though.
If your main AC voltage is 110V you need a higher VA rating.

@ all people having trouble with the newer Valabs: I hope you can all get this thing working again. Do all of you have the reclocking unit installed? That can also be the troublemaker here.

 

[rhodes54]

By the way: I've read some more stories about reclocking via the asynchronous method, like the reclocking unit of the Valab does.
They all confirmed Guido Tent's opinion: Better not to do it, especially not in a NOS DAC! You often loose more than you gain. You need a synchronous reclocking unit but they are much more expensive.

Anyway, I skipped the Tentlabs XO clock for now as it only supports one sample frequency at the moment. And as I'm often watching 48K/96K DVD's adding a clock would bring problems. Tentlabs has future plans for a new clock with resampling possibility but that will take time.

 

[PatOMalley]

I am really glad I snagged a 2008 version.
The shorter signal path can be done as a mod, no fuse, no reclock, i prefer the heatsinks myself, the ground plane seems to have benefited from Bud Purvine's wee wire on mine.

Seems like the 2008 was the last best stable.

 

[rhodes54]

Quote:

Originally Posted by Bill Allen /img/forum/go_quote.gif He Pony'ed up and installed 4.7uf Duelund VSF Copper Caps. It safe to say that the Duelund's hit the ball clear out of the park. The damn things are setting off car alarms in his neighborhood. Dogs are barking at the moon, women are dancing naked in the street. Well you get the idea ... you get what you pay for! Do to the size of the Duelund Chocolate Bar Caps he moved the entire Valab Dac board to a new case and rewired the Analog Output Section. He reports large gains here too!

Last year I decided to upgrade the filter of my speakers. After an extensive listening session with at least 10 different caps, the (meanwhile wellknown) Mundorf S/G and S/G/O and Duelund VSF's where the only three which I really loved.
I found that the Duelund had absolute tone neutrality which gave so much rest in the overal sound while the Mundorfs had a bit more transients in the high freqiencies and a slight bigger soundstage.
I finally decided to go for Mundorf as I love those transients and soundstage.

I think Tony made the right decision. I'm very curious how they sound in the Valab

 

[rhodes54]

Quote:

Originally Posted by r8833 /img/forum/go_quote.gif Rhodes54 where do buy the TexasI resistors? direct from them? ...also considering the Riedon ultra-precision Foil Resistors anybody try them @ 22.00 each Rich

You can only buy them directly from Texas Components. Just drop them a mail and they will send you a quote in a day.
They are $9,40 each. I paid $32,50 for the two resistors including shipping to The Netherlands.

 

[kevb]

Quote:

Originally Posted by Bill Allen /img/forum/go_quote.gif KevB, Not sure what is going on with your Dac but I wouldn't go sending it back quite yet. If tapping on it helps than it says mechanical connection to me. As Rhodes say that tiny fuse is a prime suspect, put whatever big fuse you have on hand in there for now. However I am with Pat on this one, get rid of the fuse all together and solder in piece of wire. With high power devices they are a necessary evil, but with low power gear I say “get em out of there”. Imagine all your power is being drawn through that cheesy little strand of wire inside the fuse. I have yet to hear of an unfused Valab Dac going Chernobyl. I have a control Valab Dac and I can tell you my modded Dac seriously outperforms the stock DAC. It’s almost a joke to put in back in my system and listen to it. I am slowing upgrading my Control Dac; DIR 9001 fs mod, Cryo Treatment, Blackgate 220uf Regulator Cap. While each mod improved the sound a little it’s still a far cry from my TP Mod. (Total Performance) I can safely say you haven't heard anything yet. Take your time and draw a schematic, then draw it again, until you “get” what you are doing & why. From my experience above, I suggest you start with a total rewire of the analog output section. Don’t cheap out on the I/V resistor & coupling caps. Welcome to the forum and best of luck on your mods. The rewards of a successful mod ... priceless!

Hi Bill,

Thanks, and I can't even comprehend that it can get much better than this! I would be happy as is, as I feel it is bettering my Stello in a few areas at this point. However, I gotta say, I nearly choked when I saw the price of the Dueland caps - I saw the >$3K price (each!!) for the silver variants. I will wait and place an order for another VALAB this week (payday), and once I receive that, I'll start on the process. For now I'm going to give this unit the benefit of the doubt and keep it for modding. Since it seems to be working fine (and sounding fine) inspite of that little operational hiccup, I'll just listen to it unmodified until the new DAC arrives. I have experienced the up and down nature of the break-in process a little....it got a little sharp and bright sounding this afternoon, but still not in a harsh way. I will bypass the fuse though....I agree with you and Pat about that hair thin fuse being a bottleneck.

The strange thing about tapping the unit to get the sound back on.....no matter what, I can't get it to even momentarily break lock once it is locked in no matter what I do - the issue (when it happens) only happens upon power up. I do have the unit with the reclocking board in it.

Jogi - I am now wondering if my issue is somehow related to the USB autoselect, as that is the highest priority input. Wish I was computer connected to test the theory. It really is too bad that the USB is not working for you....like you, I bought this for the USB input - I was looking at the Blue Circle Thingee as well, but for the same price - the VALAB seemed like a no-brainer.


Kevin

 

[Realrift]

Hi All,

Long time lurker and only recently joined after getting a Valab from forum member sum1.

It is a 2008 version and with USB 1ppm clock but no SPDIF reclock. It is being used via USB with the CM108 driver and foobar 0.9x (yet to try asio).

I liked the sound right away but felt it lacked a bit of high frequency extension and clarity and midrange seemed recessed (far away). Have alligator-clipped on cheap 0.1uF and 0.01uF caps onto the 10uF russian output caps. This seemed to help a bit with the top end and perhaps more details being available. Other than that all I have done is put heat sink compound under the heatsink and solder on the power switch which was loose and a bit flakey.

I am thinking about doing some mods and was wondering if I could get some pointers (reading my way through this thread and the first impressions one at present).

Firstly I would like to replace the output caps. (I have some Mundorf Supreme 3.3 uf Silver/Foil caps that I scavenged out of a broken second-hand dac I bought.) I was wondering if I could use this 3.3uf with a Clarity SA 1.5uf to give 4.8uf or would that cause problems (I read that using caps of the same size is bad but different sizes in parallel ok?).

I would like to bypass them with 0.1uF caps (Mundorf Silver/Oil or Vishay MKP1837 ) and some Russian Teflon 0.01uF caps.

This would mean I have parallelled 4 caps of different sizes in the output stage.

Then I need to also figure out how to connect directly to the RCA jacks and improve the grounding. Also need to read about upgrading the power supply caps (and perhaps bypassing them too).

Any other recommendations?


Ps. Thnking about getting some copper plate to make a shield around the power supply inside the dac. It will be a bugger to cut though.

Cheers,
Rift.

 

[Bill Allen]

Rift,

Welcome to the forum. The 3.3uf Mundorf Silver Caps will sound very good by themselves, forget the bypass caps for now and focus on rewiring the analog output stage.

I also have a late 2008 Valab like yours and Pat's and today I will do the "analog output" rewire mod and install Jupiter 5uf coupling caps. I will take pictures so you can see how this is done.

Stay tuned.

 

[PatOMalley]

OK, alright already. I am fetching those 5.5uF Jupiters.
I liked the chassis as I had it hotted up but the Bill's output cap argument can't be gainsaid. I wonder if that guy ever gets tired of being wrong?

What I am thinking is to remove the caps in the DAC, run the output without them then into the coupling transformer box hitting the Jupiters tied to ground then to the transformer. Does that sound reasonable?

 

[Ranchu]

I could be wrong, but I think the cap goes to the transformer input winding, rather than ground, the other side of the input winding then goes to ground.

I think.

 

[PatOMalley]

My line pre and phono pre both have 1uF output caps so why can't the valab?
Shouldn't cut down on bass, I suppose, because that phono pre really delivers in that dept. AND I get to keep my chassis as is.

Out went the BG + Obbligato + Teflon combo, in goes Obbligato 1uF / 630v.

Needs breakin, real weird at startup, but after 60 minutes there is that PRaT thing. More toe tapping. Not a big deal, I am really behind the curve on the single output cap deal but just wanted to input that going as low as 1uF looks to be AOK. Anyway it does seem like the electrolytics did make things a little dense and heavy. Not it seems a little more honest and springier.

I do not sense any loss in bass ... Same thing happened when I changed the output caps on my CDP. I put 1uF in first then thought "maybe I should have used 4.7uF". Put the 4.7uF in and no real difference in bass response. I think going _below_ 1uF you might lose some bass ...

 

[Ranchu]

Cool lookin.

These pics are killing me, mine is redelivered tomorrow!