[dcolak]

Quote:

Originally Posted by tubes /img/forum/go_quote.gif The Valab uses 390R for the DAC i/v resistor, which will make the DAC output maximum 2.19V. In some systems, this high voltage may produce clipping. In this case, the i/v resistor could be changed to 330R to reduce the DAC maximum output voltage to 1.8 V.

Can someone verify this (and maybe post the pictures)?

It would be a nice solution to all our problems with the distortion

Edit: I tried the DAC with NAD C370, Trends TA10.1 and Icon NuForce - it was clipping on all of them.

 

[crumplertm]

Quote:

Originally Posted by dcolak /img/forum/go_quote.gif Go to: Start->Control Panel->Sound->Select USB Audio->Properties->Advanced Turn up just a little bit your amp, so that you can hear the sound. Hit the TEST button. What did you hear? By the way, you should use foobar at 100% and control the volume with your amplifier, that is the best way to listen to the music from PC - regarding the noise level and the resolution (16bit?). With foobar at just 30% you're forced to turn up the volume on your amplifier much more than it is necessary with the foobar at 100% and the amp's noise floor becomes more prominent. Really, it is more than normal to have your foobar at 100%, but, with Valab and Gigalabs moon dac it gives you a nice quantity of distortion.

I tried your test and found that I only had 16 bits 44100 and 16 bits 48000. No 24 bit option for me.

As for the volume at 100% in foobar I did notice mild clipping.

 

[dcolak]

Quote:

Originally Posted by crumplertm /img/forum/go_quote.gif I tried your test and found that I only had 16 bits 44100 and 16 bits 48000. No 24 bit option for me. As for the volume at 100% in foobar I did notice mild clipping.

I'm sorry to hear that. We all have the same problem, I guess.

Regarding 16/24bit, it is ok, I also have only 16bit with the original Windows driver. It is distorting with the 24bit too...

 

[crumplertm]

Quote:

Originally Posted by dcolak /img/forum/go_quote.gif I'm sorry to hear that. We all have the same problem, I guess. Regarding 16/24bit, it is ok, I also have only 16bit with the original Windows driver. It is distorting with the 24bit too...

Seems like an inherent problem with the design.

 

[DrCal]

Quote:

Originally Posted by dcolak /img/forum/go_quote.gif Can someone verify this (and maybe post the pictures)? It would be a nice solution to all our problems with the distortion Edit: I tried the DAC with NAD C370, Trends TA10.1 and Icon NuForce - it was clipping on all of them.

I second.
Also, it would be interesting to hear from those who modded their Valab DAC extensively and see if clipping still exists...

 

[jlaakso]

Quote:

Originally Posted by DrCal /img/forum/go_quote.gif I second. Also, it would be interesting to hear from those who modded their Valab DAC extensively and see if clipping still exists...

the heavily modded ones were from earlier batch/revision. This clipping/distortion seems to be flaw of the recent batch. someone said QC does not negate everything, but it does render this batch quite unstable and one would not recommend buying this before valab addresses the problems. Is it QC or design flaw, I do not really care, anyhow I will not consider this DAC before these issues are solved. My opinion, my money.

 

[tubes]

What I posted earlier about the resistor value was what I received in response to an E-Mail I sent the MFR. of the Valab. The 2.19v output with the 390R in place is similar to other dacs on the market so changing to the 330R is not a magic bullet to cure the problems with distortion but may help in certain systems. I know that using a PC opens a can of worms I don't want to get into but the use of a CD player as transport should not produce distortion.

I'm just curious but how many hours do you guy's have on the dac that are having distortion problems?

 

[dcolak]

Quote:

Originally Posted by tubes /img/forum/go_quote.gif What I posted earlier about the resistor value was what I received in response to an E-Mail I sent the MFR. of the Valab. The 2.19v output with the 390R in place is similar to other dacs on the market so changing to the 330R is not a magic bullet to cure the problems with distortion but may help in certain systems. I know that using a PC opens a can of worms I don't want to get into but the use of a CD player as transport should not produce distortion. I'm just curious but how many hours do you guy's have on the dac that are having distortion problems?

Hm, I have months of use

- Gigalabs Moon DAC, returned one, got another from the MFR. with the same problem. Thought of Valab, because they share the design, wanted to see if it suffers from the same problem before ordering one. Alas, it does.

It clips not only with a cd player, but with the squeezebox as well... The solution with the squeezebox is the same used on a PC, lowering volume in the digital domain.

 

[DrCal]

Those of you who have heard distortion using Valab with CD/DVD transport, please post your testing CDs and specific tracks so that the rest of us can try to see if the same problem exists in ours? Thanks.
As I said, I have not heard from other cases except PC/C-media/Windows Vista test sound/USB/Valab. (oh, does the test sound from Control Panel go through Foobar?)

 

[dcolak]

Quote:

Originally Posted by DrCal /img/forum/go_quote.gif Those of you who have heard distortion using Valab with CD/DVD transport, please post your testing CDs and specific tracks so that the rest of us can try to see if the same problem exists in ours? Thanks. As I said, I have not heard from other cases except PC/C-media/Windows Vista test sound/USB/Valab. (oh, does the test sound from Control Panel go through Foobar?)

Don't forget that it appeared also when used SPDIF output of a soundcard to drive Valab!

It's not only USB, SPDIF is the same.

I'll try to get and upload a couple of MP3's that distort clearly (wavs distort just as much).

Control Panel goes directly to DAC (over USB and/or SPDIF), no foobar in between.

 

[tubes]

Dcolak, you've had this problem with 3 dacs now, do you get distortion with the output of the Squeezbox or the CD player? What's the rest of your system, it seems strange that you get distortion with 3 dacs. Do you get distortion if you take the PC out of the system and just use the CD player as a transport into the Valab or Gigalab?

BTW, people that have modded their dacs never mentioned hearing clipping before or after modification.

 

[microzyma]

Audible clipping at 0db 1khz using Sheffield test cd with foobar/asio,

 

[paara]

Quote:

Originally Posted by Shark_Jump /img/forum/go_quote.gif Dear all, I was hoping someone may be able to help me out. My Valab DAC has never worked (see thread last Tuesday). I have emailed Kevin at Valab 3 times since then about returning the unit and I have not yet received a reply. Does anyone know if Kevin reads this thread or is anyone in regular contact with him? If so could you ask Kevin to make an effort to get back to me. I was thinking to post it back anyway as there is an address on the mail, however I can't read the numerals on the address/zip code and I am reluctant to send it back without prior agreement with Valab. Any help would be appreciated.

Sad to hear that.

I thought of buying a VALAB, but reading about nonfunctional units and clipping I think not.

Hope you will be sorted out.

I got a respons after 24 hours by contacting him through ebay

,Stian

 

[microzyma]

On the bright side, the unit is much more musical at -3db. hehe

 

[MikeW]

for people looking for a "test" track, if your using Foobar on a PC there is simple answer, foobar's built in tone generator. Goto Add location, then type tone://40 in the field, this will generate a pure 40 hz tone, makes it extremely easy to hear the distortion.