Sinus Live SL-A3000

Hi guys!

I'd appreciate if anyone of you have the schematic on the SL-A3000 and could email it to me.

I got a small DC offset on the output and that voltage follows the bassboost pot
0dB -> 1.02V on the output
12dB boost -> 1.2V on the output.

The amp is not mine. The guy who owns it says it killed his woofer but it sounded alright and just went dead.
HF maybe? Or is it the DC voltage?

Cheers!
Markus - Sweden