Adding a volume control to a TPA3122-based audio kit

[i336]

Hey everyone first post!

A friend recently gave me one of his spare audio amplifier kits and I'm trying to figure out how to best add a volume control onto it. I'll admittedly be driving it from my PC, but I far prefer a hardware control (like my current tiny amp has).

Here's a schematic:

I asked on Stack Exchange and was recommended to just put a 5K pot on the inputs. If that's the best solution I'll concede and do that, but I thought I'd ask somewhere a little more... authoritative first P).

In particular, I keep looking at the GAINA0/GAINA1 lines; they seem... potentially very interesting. Could I replace the switches the kit uses and add some combination of pots here?

Thanks in advance!

- i336_

 

[Saturnus]

In particular, I keep looking at the GAINA0/GAINA1 lines; they seem... potentially very interesting. Could I replace the switches the kit uses and add some combination of pots here?

No. As the data sheet says. It's a fixed gain setting. It reads the voltage resulting from the combination of resistors and sets the gain accordingly at power up. To change gain setting you must cycle the amp power off and on again.

 

[i336]

...Oh. Oh wow.

My friend actually uses one of these exact same amps himself... and I was at his house not too long ago, we were listening to some music, and he flicked the switches to boost the volume a little.

While the unit was on.

I had no idea that wasn't supposed to work.

Looks like the chip has some undocumented deviances from the spec. :/

So, per specification, my best bet... would indeed be to add a volume control on the input?

Presuming "yes," what if the speaker output from my sound card splits up before going to this amp? Will a pot on this half of the split affect anything? I'm guessing not but I figure I might as well ask...