Protection mode issue on integrated amplifier

Gotcha!

 

When I engage Power Amp Direct the Marantz basically turns into a power amp. I can not select any sources, source select becomes disengaged.

 

Well that's somewhat undocumented behavior from the manual, but thought there was a chance it would work like that.

A less dumb amp than the Marantz would use the "Pre-Out"/"Direct Amp In" combo like an effects loop - you could use either, or even put an EQ or RCA jumper between the preamp and amp.

About all we can do now is isolate the two components. I'd try one of this style "ground loop eliminators" between pre and amp:



It's a stereo set of transformers that eliminate ground loops, and will also reduce some problematic low frequencies. This one I pick for you because it has 1.5dB gain, which means that the reverse direction has 1.5dB attenuation. Not super audiophile, but under $10 to try a cheap one.

 

Thanks. Not sure I want to get into something like that though.