Headroom Micro DAC and problem with USB input.
May 16, 2007 at 8:40 PM Thread Starter Post #1 of 23

schugh

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I just received my Micro DAC a couple of hours ago and I have it hooked up to the Micro Amp I got last year. I have them hooked up and am using the USB input connected to my notebook and playing back some flac files which were ripped using EAC. I am using foobar200 for playback.

I am finding many sound artifacts occuring when listening through my Grado 225s. I am not sure how else to describe it better. But it's like the pops and clicks on a poorly ripped CD. But my music files are fine because when I play them back straight using the optical input on the DAC and my iRiver H140 then I don't get any of the artifacts all.

Has anyone else ever noticed this? If so what could be the cause? Could it be having other devices connected to my other usb connections on the notebook?

I am not sure what is going on here. I would appreciate any insights if anyone else has run into this problem.

Thanks,

-- Sanjay
 
May 16, 2007 at 8:44 PM Post #2 of 23
Sorry for the very basic response, but are you running the MicroDAC on batteries? If so, replace them and see if that does the trick. My MicroDAC used to misbehave badly as soon as the batteries started going south.
 
May 16, 2007 at 9:37 PM Post #4 of 23
I've had a Micro DAC for probably six months now and I couldn't be happier. Never heard anything bad from it like you've described. I've only ever run it on mains power though.

GAD
 
May 16, 2007 at 9:50 PM Post #6 of 23
This is very strange indeed.
I've noticed a pattern of when this happens. I was browsing the web earlier while listening through my headphone setup.
I've noticed if I start my firefox browser and it goes to the home page. As soon as the little progress bar finishes letting you know the page has loaded, I get a distorted sound artifact. It's not a sound event as I don't have any sounds associated anywhere for anything. And it seems as long as I have the browser open I keep getting these artifiacts. As I am typing this message for example. But if I close the browser then the artifacts stop.

Very strange. I will try the buffer size.
 
May 17, 2007 at 3:30 AM Post #7 of 23
Hi Schugh,

What you're describing is certainly not normal. If you happen to have access to another computer I'd suggest trying the DAC with it and if you still have the same issues contact us directly via e-mail or phone so that we can arrange to send you a replacement. If it doesn't happen on the other computer then we should be able to fix the problem over the phone or via e-mail without you having to ship it back to us. Mike Olson, mikeo@headphone.com is our tech support manager and is the best person to assist but I would be happy to help too. jamey@headphone.com

Let me know if I can be of further assistance.

Thanks,
Jamey
 
May 17, 2007 at 3:36 AM Post #8 of 23
Thanks Jamey. I was already thinking of calling you guys tomorrow.
I am at home right now and will try it on my desktop computer shortly and see if things are better.

-- Sanjay
 
May 17, 2007 at 3:38 AM Post #9 of 23
Quote:

Originally Posted by schugh /img/forum/go_quote.gif
Thanks Jamey. I was already thinking of calling you guys tomorrow.
I am at home right now and will try it on my desktop computer shortly and see if things are better.

-- Sanjay



Also, Sanjay, to continue with my basic rule-out suggestions, have you swapped out the USB cable?
 
May 17, 2007 at 4:03 PM Post #10 of 23
Well, it appears I must have a really special thinkpad.
I connected the dac to my desktop at home and everything worked flawlessly. No problems at all.
Connecting back to my thinkpad and the problem was again very evident.

However I have managed to narrow things down somewhat. It appears that at least half the problem has to do with Google Desktop Search which I installed a couple of weeks ago. If I shut it down then I don't get the pop when I open firefox. When I start up Google Desktop again the pop when starting firefox is back. This is completely repeatable. I uninstalled Google desktop for now to see if the other half of the problem would go away and unfortunately for me it hasn't.

I would say about 15%-20% of the time when I click on links etc in firefox I get the pop again. Then also as I am typing this message I get 2-3 pops a minute.

I've just now also tried this on a collegues same thinkpad. His software config is probably somewhat different but the notebook is the identical thinkpad t60p. He has firefox on his machine and the problem does not manifest on his machine either. It seems to only happen on my machine.

So I am very confused what is going on in my notebook. I don't understand how software such as google desktop for example could corrupt the usb stream to the DAC causing the pops. And now is there some other software causing similar problems when I browse the web? Very weird.

-- Sanjay
 
May 17, 2007 at 4:22 PM Post #11 of 23
I've experience a pop like this every once in awhile on my desktop when I switch from one URL to another in Firefox. It's intermittent, though. It could be a bug in the browser. Have you tried it while running a different browser? I don't own or use the HR micro units.
 
May 17, 2007 at 5:22 PM Post #12 of 23
I have had this happen with my wireless usb mouse scrolling in firefox...
 
May 17, 2007 at 6:49 PM Post #13 of 23
I've had similar noise problems with my laptop. I thought it was due to ground loops. I guess different apps put different loads on the chips, causing different amounts of noise. Your observation is very interesting.

In any case, if you want to utilize the Micro DAC, get a another USB sound device with digital output and connect it to the Micro DAC. That's why I bought a M-Audio Transit.
 
May 17, 2007 at 10:13 PM Post #14 of 23
I had this exact same problem with my T60 thinkpad at work. It was driving me nuts. The problem appears to only exist on the USB ports on the laptop itself. If you have a docking bay, that will fix the problem (not sure why). That's been my solution.

Apparently, on many laptops with ATI x1300 video cards, there is a conflict between the video card and the usb system. It's not the audio card or the OS per se, so no driver fix will help. If you're truly having the same problem I was having, you may notice that the clicking and popping is correlated with 2d graphics refreshing (drag a window around, have a web window load/refresh).

Good luck!
 
May 17, 2007 at 11:33 PM Post #15 of 23
Hey JosephJFK, I just tried to drag windows around and you are right, the same problem happens randomly when I do that. Sometime I have to drag the window around for 15-20 seconds before I hear it and then other times it happens several times withing a few short seconds.

I thought I had tried the usb port on the dock today, but maybe I am forgetting. I will try it when I am back at work tomorrow.

My thinkpad has the ATI mobility firegl 5200 video card.

And you are right: this is driving me nuts. My main purpose for the dac was to use it with my thinkpad at work.

-- Sanjay
 

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