"Great its just what I need to amplify the headphones output of the MP3 player! I'll just move those input wires straight to the input of that IC".
This IC is apparently the main, higher power amplifier for the speakers. There's another IC, an LA7769 (fourth/fifth pics) whose output goes straight to the speakers. I looked up this chip on at a great Data Sheets website (see third pic) and found that it is an Equalizer Amplifier that is apparently acting as a preamp for the tape head. A great idea!! Thanks unknownuser2007! The tape head wires (which I am using as the input from the MP3 player) are attached to the circuit board and traces ran from there to an LA3220 IC chip (see second pic). Update 10-07-07 Adding resistors didn't seem to be helping then I got a suggestion from another great Instructables user, unknownuser2007 He suggested that instead of trying to use resistors to drop the level of the headphones output of the MP3 player, I could try bypassing the cassette head preamp IC like he did in his instructable.
Next I tried 3000 ohm resistors, but still hardly any change. After trying it, it didn't seem to make much difference. For testing I just soldered them in just sticking out until I find the right size. I'll try adding larger resistors in series. Ok the 150 Ohm wasn't enough the sound is still distorting a bit.
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