I finished that mother@#$%er - of course, way too late to be of any use to what I intended it for, but hey, it's my first finished project in ages, if not ever. I'm entertaining the thought of building some portable speakers, perhaps a 1W practice amp with this IC. Sure, the LM386 might have some interesting gimmicks, such as the variable gain, but the 2822 is pure gold! Just gotta find enough of them for all chanels (the KA2209 is a pin-compatible substitute, by the way, but I'm not sure whether both are equally good).
At 10V, the amp is LOUD - so loud that I have to turn my PC's volume control down to 1-5% just to be able to listen to this through my Sennheiser HD407s (which are really nice for their price, by the way!). I get a lot of white noise, some 60Hz hum, and I can even pick up some radio if the other end of the cable is unplugged. All that noise is really fun, but it has to go, so I have some questions about what I can do.
My actual setup is: input jack -> 4x 20kB stereo pots -> 4x TDA2822 stereo amps -> 4x output jacks. I intend to plug this thing not to already preamplified headphone outputs such as my laptop's headphones jack, or my USB soundcard's headphones output.
1. I'm gonna put a voltage divider, or perhaps a trim pot at the input jack. Do the actual values matter? I.e. is there a difference between using 10k:100k vs. 100k:1M?
2. How do I taper 20k linear pots to become 10k logarithmic again? And would that be detrimental in some way, to something?