Valab NOS DAC - subjective listening and modifications - Page 120

not sure about the Dir mod, but with those tiny connectors it could be that one although I reckon it sits inthe digital domain so mono is not a typical result of anything going wrong there.

(have no access to the schematic right now, will ckeck later if needed)

I spoke to the guy who helped me with it and it turns out we probably did the I/V resistor mod in the first lot, as in together with the output caps. They may well be the reason for my grief, although we have already undone & redone all the mods except for DIR9001 to be sure. Who knows, maybe third time's the charm?

This is why one shouldn't take long lapses between unsuccessful modding, it is easy to lose track of what was done exactly when.

I always mod one step at a time, and rarely do more than one....learned the hard way...
As a nice side effect this method will also provide you with valuable listening experience allowing you to hear the effects of each mod, also allowing you to go one step back in case the result is not as targeted (allows you to develop a taste for types of caps and resistors that will help modding at a later stage as you then can tweak the sound of the nearly finished product by using particular flavours).

DIY High End is like cooking food, throwing together some high Quality ingredients does not necessarily deliver michelin star worthy food...

Just a quick question - is burn-in considered important for the Valab, and if so, how many hours does it need?

Valab MK-1 luxury version

Hi guys-
I hope I'm not violating forum protocol by asking this question, but I figure it's best to go right to the experts for advice. The amount of knowledge on this site is truly awesome, but a bit intimidating to an amateur like myself.

I have a Valab Dac which I bought in March of 2009. I really like the sound, but I recently noticed the Luxury MK-1 version on Ebay. So..would an upgrade be
an audible improvement or should I stick with what I have?

Any advice from you guys would be MUCH appreciated.

Thanks, Rich W

the difference would be audible as the lux version has an improved power supply, but the extent of the improvement might be limited by the rest of your audio chain.

Valab MK-1 luxury version

Hi marcelnl-

Thank you for the quick response!
My system is on a desktop-a pair of Avi-ADM9.1's, which I suppose are fairly revealing, and a Velodyne micro-vee sub under the desk. I've used good cables throughout(a Kimber USB), and have used several acoustic panels on the walls,
which do a great job, and XXHighend software. All in all, it sounds pretty good for a "desktop" system, but I'm always looking for improvement.

Thanks again, Rich W

Maybe you have one of the very unique Valabs with the bench revised 330r IV resistors and no damn TCXO between the SPDIF and DAC chips. That's a desirable configuration for people with very high quality SPDIF sources. If you decide to sell it, you should confirm that it is indeed that revision and put it on the block as such. Tho, may or may not get more for the sale. I also suggest you go back in the Valab forums here in HF and read about the DAC in the period of time you purchased it.

Otherwise, the luxury model might be better for you than the March 09 Valab depending on how you feed it. Like marcelnl says, the much better power supply is a big plus.

Where does the Valab fit into that? The Avi have a DAC built into them.

The guy that makes those speakers has a view on the audible effects of jitter that I disagree with. I've been curious to know how that plays into the quality of Avi system's DAC and its ability to reproduce a stereo sound field. They're suppose to be very nice sounding on their own.

Valab MK-1 luxury version

Hi Newk Yuler,

Yes indeed the Avi's do have an internal DAC. I have a toslink connection to that DAC and have listened to it a lot. It sounds very good, great detail-but I
keep switching back to the Valab, which I owned before the Avi's.
Maybe it's the NOS sound that I prefer, but the Valab is more appealing to me than the Avi's DAC. I'm sure there's many people who would disagree with me on that, not the least of which would be the owner of AVI!

Rich W

Is there any information out there on how to bypass the TCXO between the SPDIF and the DAC chips? I have a Luxury version and would like to bypass this to hear if my system sounds any better without the TCXO. I am running a Mac Mini with a M2Tech HiFace USB/SPDIF convertor.

The short answer is 'no'. It's a good question because if it's possible, no one capable of doing it has done it or at least discussed it here, but the issue has been brought up more than once. Before the Hiface came around, most people would probably benefit from the TCXOs to some degree. (Hiface or similar async USB input device.)

It does indeed suck to know you've got a great input with the Hiface and come to realize that you may be degrading it by running it through a TCXO. It's a very good reason for a prospective buyer to look for an alternative DAC. TeraDak and Valab need to understand that.

I really do not understand how a reclocking circuit works so I will spend some time and try to figure out. I think there must be a way to connect the SPDIF input directly to the DIR9001? How is the connection made on the previous boards that do not have the reclocking cuircuit on the SPDIF input?

Valab MK-1 luxury version

Hi Newk Yuler,

Ya know, now you got me thinking(and that's never good); I'm 99% sure that my Dac is the one that you describe, and if that's the case, maybe I would be better off getting the Hiface and trying that with this Dac. Hmmm.

Rich W