I just installed a Clarion PorAudio DXZ835MP CD player in my 2002 SLK230. First I used the pre-amp outs to drive the Bose amp. In using the new h/u I noticed that every time I changed a setting (skip/ff/source change/etc.) there was an annoying pop coming out of the speakers. My assumption was that the h/u had a problem. So, I returned the unit and got a replacement. The replacement did the exact same thing. Next I changed the wiring to use the speaker level outs and voila, all is well. Somehow when I change a setting, the pre-amp outs are generating a signal that the Bose amp reproduces as a pop. I'm not familiar with electronics enough to know why, so at this point I'm forced to use the speaker level outs. The sound is good but my perception is that it's not quite as clean as using the pre-amp outs.

Can anybody offer an explanation? Even if there's nothing I can do about it, I'd like to know just to satisfy my curiosity. Just FYI, this unit has 4volt pre-amp outs.

Thanks,
Sandro.