[dcolak]

Quote:

Originally Posted by Quicky /img/forum/go_quote.gif I think this is possible, but I would say it is more to do with the 'NOS'-ness of this DAC, personally. I say this because comparing the Valab to a Moodlab NOS DAC I have, they both have the same 'flavour' to the sound which is quite laid back and smooth.

Unfortunately they both have the same distortion

 

[dcolak]

Quote:

Originally Posted by erin /img/forum/go_quote.gif Hmmm... Im using Windows XP and so dont have the test tone available in the control panel I so far haven't heard any distortion from this dac, could it be a Vista issue? I have a CRO so will make some test tones and then observe the output of the DAC on screen. This should give a definative answer to this distortion issue. I will post my results in a few days..

It's not Vista issue, it's there even when using a CD player as a source.

If you have an XP, there is a simple method to test your DAC.

Put the volume in XP to 100% (using the little speaker near the clock in the task bar).

Put your amp volume a bit higher, so that you can hear clearly.

Then, go to control panel -> sounds and audio devices -> sounds -> select a window sound, for example Asterisk an press play (you can try that with a couple of different sounds that you see in the list).

If you hear it distorted (sounds like the amp is clipping, as if you were playing it too loud) - you've got the same problem.

Judging from what other people said, it is a common problem with Valab and Gigalabs Moon Dacs.

 

[Quicky]

Quote:

Originally Posted by dcolak /img/forum/go_quote.gif Unfortunately they both have the same distortion

Ah you mean the inherent distortion of NOS design?

Yes I can't argue with that point.

But for the record, the Valab-specific distortion is very different to any characteristic that I have heard in any other DAC. It sounds like clipping and only seems to occur with certain frequencies.

 

[dcolak]

Quote:

Originally Posted by Quicky /img/forum/go_quote.gif Ah you mean the inherent distortion of NOS design? Yes I can't argue with that point. But for the record, the Valab-specific distortion is very different to any characteristic that I have heard in any other DAC. It sounds like clipping and only seems to occur with certain frequencies.

I was thinking of the "clipping."

The idea of the NOS sound is something I do like.

 

[Quicky]

Quote:

Originally Posted by dcolak /img/forum/go_quote.gif I was thinking of the "clipping." The idea of the NOS sound is something I do like.

Ah right!

Well, I found some tracks that always distort on the Valab, then tried them on two different Moodlabs and neither 'clipped' on the parts of the tracks that distorted on the Valab.

My personal opinion is that it was definately a problem with the Valab, certainly that particular unit I had, and was not specifically to do with the fact that it was NOS.

 

[julius_the_cat]

I had my Valab "cooking" with a continuous input signal for the past week since it arrived and took just a few peeks at the sound before last night. Listening to vocals with a fundamental frequency of about 200 hz, audible and unpleasant distortion (clipping).

Windows XP with J River Jukebox and Direct Sound into a Delta 44 soundcard SPDIF out to the DAC. I will try another audio card and speakers as I am able this week.

I had a friend looking for a new DAC (he is still using a DITB) and I cannot suggest purchase of a Valab until this issue sorted out.

Disclaimer: I have not exhaustively evaluated my other gear yet and I may be unjustly accusing the Valab. FWIW

 

[tubes]

I've never used a PC with the Valab and have never had a problem with distortion. In talking to someone that uses the Valab with a PC and loves it, tells me Vista cannot be used in the mix. If you're using a CD player as a transport and getting distortion you have something wrong with the dac, if using a DVD player check the digital out settings, try PCM.

 

[dcolak]

Quote:

Originally Posted by tubes /img/forum/go_quote.gif I've never used a PC with the Valab and have never had a problem with distortion. In talking to someone that uses the Valab with a PC and loves it, tells me Vista cannot be used in the mix. If you're using a CD player as a transport and getting distortion you have something wrong with the dac, if using a DVD player check the digital out settings, try PCM.

The distortion (clipping) is there, with either USB or SPDIF, whether the source is a cd player, dvd player, squeezebox, sound card with spdif or a pc with an usb.

It has nothing to do with Vista, unfortunately.

 

[rbej]

Kevin!!. Give us our money!!

 

[adam2434]

I definitely had clipping/distortion on some tracks with my previous NOS DAC – the Lite DAC-ah (which is very similar to the Valab, but uses an op amp in the output stage). I forget the exact details, but read that this was caused by something running at the wrong voltage on some units – really more of a quality control issue.

However, I have not heard the clipping/distortion on some of the same tracks with the Valab, but I have not tried all the tracks that produced the clipping/distortion on the Lite.

For those who have experienced the distortion with the Valab, it would be helpful to list the track info and time so that others could test the same track, if they own it.

 

[adriaan243]

I believe you are completely wrong. The USB has MUCH less problems than SPDIF.

I am using a computer all the time, using either Pyramix or Sequoia professional software and professional Asio drivers.
What happens in Windows, Foobar and C-Media is unclear and no professional would use it.
My Valab sounds clean and nicer then most more expensive DA converters.
But it is possible that the Valab implementation of USB is wrong, the only thing I wanted to say is that through SPDIF my Valab sounds fine,it is a pleasure to listen to well recorded CD's in fact more so then through my CD/SACD player and it does not distort.

 

[tubes]

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.

 

[Quicky]

It would be great if someone who is experiencing this distortion could create a test tone or track which others can use to verify/disprove this distortion issue on their Valab.

My experience was that it took me a while to notice this distortion as it only happened on certain tracks.

If anyone has the Bon Iver EP 'Blood Bank', the second track distorted quite a lot at various points for me on the Valab, it's a good test track for this particular issue I found.

 

[crumplertm]

After reading many facing distortion/clipping problem, I would like to share the configurations that I use which I face no distortion.

Im using Windows Vista Running Foobar > Wasapi > Usb Connection to the dac.

I used the configuration recommended by a forumer here

http://www.head-fi.org/forums/f46/ea...5/#post5316393

So far so good, the windows volume in the system tray is unable to control the volume. I set foobar volume to about 30% and disable all gain functions.

So far so good with the 2008 version dac.

 

[dcolak]

Quote:

Originally Posted by crumplertm /img/forum/go_quote.gif After reading many facing distortion/clipping problem, I would like to share the configurations that I use which I face no distortion. Im using Windows Vista Running Foobar > Wasapi > Usb Connection to the dac. I used the configuration recommended by a forumer here http://www.head-fi.org/forums/f46/ea...5/#post5316393 So far so good, the windows volume in the system tray is unable to control the volume. I set foobar volume to about 30% and disable all gain functions. So far so good with the 2008 version dac.

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.