Behringer UCA202 - Any "Line Out" mods??

[Karl vd Berg]

Hi there.

I was wondering if anyone has ever done any mod in a DAC before.

I've read the NwAvGuy's Behringer UCA202 DAC modifications, but it seems that he did the mods for the headphones output only.

I have the UCA202, too (first pic).

The 2nd picture below show two 22uF/6.3V caps (C4, C5) close to the RCA outputs. At the end of NwAvGuy's article, he states the following:

OTHER TWEAKS: As mentioned above, the feedback loop could use some attention. Optimizing the feedback should remove the slight 0.4 dB rise at the highest frequencies and might improve the sound. And I suspect using higher quality output capacitors might lower the output impedance still further. The problem here is finding better parts that will fit inside the original case. All my modifications fit completely inside (although I did have to cut a plastic post off the inside of the case). Better audio-grade output capacitors (and possibly adding quality bypass caps) may also improve the sound quality and further lower the output impedance. It might also be possible to improve the channel separation with some tweaks to the power supply lines feeding the new amp IC.

He's actually referring to the other two 100uF/6.3V caps (C14, C15 pointed in the 3rd picture below) which he changed with 2200uF/6.3V ones which are close to volume pot (for the headphones):

Now, I'm not sure if C14 and C15 affect also the RCA lineout for audio... or just for the headphones jack.

I'd replace the caps for audio out with better quality caps.

Any idea?

 

[so_ein_pech]

Since line-out connections are typically used to drive very high impedance loads, you don't need to worry as much about the output impedance of the DAC. This sort of negates the entire reason for doing the mod in the first place (which was to get the output impedance as low as possible).

 

[Karl vd Berg]

Okay, thanks! I might leave it like it is and do a mod in another early and simple model (UCA200, like this) I lent to someone, but will only replacing same values caps with new Panasonics or Nichicons...

 

[Karl vd Berg]

... and finally I decided to "upgrade" this cheap DAC before looking for another one. Put in the order a few Panasonic FR, FC for C1, C6~C13 and C17, and two Silmic II for C4, C5 output caps... All rated 35V (25V for C13), replacing the 6.3V stock ones.

Stock caps were still good on capacitance values, but showed very poor ESR numbers...

So here it is...