[srb]

Alright everybody. I will be brave and report back (if able).

Our prayers are with you.
 
Steve

[timind]

If they were really dangerous don't you suppose they'd come with some warning or a liability disclaimer of some sort?

[Mass. Wine Guy]

Plug mission accomplished. Hum still present. Hmm. What should I do next?

[Wayner]

Disconnect everything except amp, preamp and speakers. Do not have any component plugged into the preamp, interconnects or even power cords. Put the preamps input selector to a line level input and turn everything on. Is there hum now? If so, get new amp.

Wayner

[Ericus Rex]

Try Wayner's suggestion but if there is still hum, put some distance between amp and pre before trashing the amp.  If you still get hum, then the amp is faulty.

[Mass. Wine Guy]

Disconnect everything except amp, preamp and speakers. Do not have any component plugged into the preamp, interconnects or even power cords. Put the preamps input selector to a line level input and turn everything on. Is there hum now? If so, get new amp.

Wayner

Thanks, Wayne. Can't the amp be repaired if it's at fault?

[Wayner]

Try Wayner's suggestion but if there is still hum, put some distance between amp and pre before trashing the amp.  If you still get hum, then the amp is faulty.

Ericus brings up a point that I forgot about. Perhaps the new amps power supply has a stronger magnetic field from the power transformer and is trashing up the preamp. Yes, as Ericus has stated, get some longer interconnects and move the preamp away from the power amp. Maybe this will reduce or cure the problem.

Wayner

[Speedskater]

Like Ericus & Wayner wrote. 
One unit's power supply can effect another unit.
Now with SMPS's and digital circuits, even stranger things can happen when units get together.

[Mass. Wine Guy]

My preamp must be about one to 1 1/2 feet  one foot from the amp through a wood divider. Could the power supply be that powerful?

I disconnected and unplugged the DAC, switched off the CD player and disconnected it from the preamp (didn't unplug it, though). Turned amp on, hum still there. At this point I'm going to request that the seller take the amp back. The hum was there when I received it. He said it was dead quiet in his system.

[Wayner]

Wood does not stop magnetic fields. You need either distance or metal (steel, mu-metal, others) to stop the field. Are your interconnects well shielded?

Wayner