By all means, go for it, but surely a nice wee HiFi preamp kit would save you much headache and stress trying to reverse engineer that LCD? Seriously - considder taking a look at any pre-amp based around the LM833 - this is an Op-Amp designed specifically for HiFi audio work - I will see if I can find the datasheet and upload it here.
The TDA2822 is a stereo power amplifier chip in an 8-pin DIL package.
Last time I used one, they were quite impressive(at the time), but I remember them being quite noisy - significant white-noise in the background, especially noticeable with the amp powered but idle(not amplifying anything).
IC based pre-amps and indeed, power amps, have taken quite a jump in the last few years in terms of quality and performance, and there are definitely better ones out there then the old 2822.
Still, if you are looking for something to do...
EDIT: Found and uploaded the 833 datasheet - this is still an impressive device, and it has been around for about 10 years at least - please correct me if I am wrong. With an 833 based pre-amp feeding a half-decent stereo system, you will blow your socks off, and it will be good quality sound - I know, as I have done it, and it sounds a million bucks.