Re: [LAU] status usb2 for sound

Dominic Sacré wrote:
> On Friday 06 of November 2009 19:55:25 Martin Homuth-Rosemann wrote:
>> you're right - the pcm2902 codec is broken by design. The internal
>> voltage reference shows a terrible distortion because the 1 kHz usb
>> clock isn't decoupled properly. The data sheet
>> (http://focus.ti.com/lit/ds/symlink/pcm2902.pdf) recommends the use
>> of an external voltage reference for "a high-performance application"
>> (figure 37) - unfortunately Behringer uses the circuit for "a simple
>> application" (like figure 39).
>> I tested my UCA202 with Fons' jaaa and got a "nice" peak at 1 kHz -
>> it went away after adding a REG103-A to my UCA (you can get free
>> samples from TI).
>
> Hi Martin,
>
> How do you "add" a REG103-A? Do I need a deep knowledge of electronics,
> or would a soldering iron be enough? ;)
>
> I've got a UCA202 which causes a very audible, pulsating noise at
> multiples of 1 kHz while running Jack. If there's a way to fix it, I'd
> like to try. Of course the device was cheap, and as it is it's pretty
> much useless to me, so I'm not all too afraid of breaking it...

Strange, I've got a UCA202 that doesn't have any such noise at all.

I used to get noises when I had it plugged in via a self-powered
external USB hub.

-- 
David
gnome@hawaii.rr.com
authenticity, honesty, community
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