power conditioner

I had Furman n they were good.....but that was before they sold the company.....my friend didn't want 2 buy mine so he bought a new one.....this was after Furman sold....bought it at B&H Photo around were we both worked.....he didn't like it plus it hummed so he returned it n bought mine.....he like n kept it.....all I said 2 him was.....I told you.....this was back before 2009....good luck everyone.

 

@lostbears 

power conditioners are not designed to address hum (if coming from your amps transformer). This is why you need a DC filter.

I recommend - what I use - an Emotiva CMX-2. Besides the fact that it "works", it is inexpensive (less than $100 if you wait for sale which Emotiva runs regularly) and doesn't limit current in any practical sense (i.e. technically it is not 100% passive but is 99, given the meaningful LEDS)

 The hum was definitely coming from the preamp. The cause was a compact  fluorescent bulb in the dining room. We don't use the lights in dining room much. The bulb was putting noise in the line. You turn the lights on, the preamp had a hum. You turn them off and it was gone. Curiously the two rooms are not even on the same breaker. There was no ground loop. It never happen before or since. So I presume the old Adcom Ace 515 that I was using again before I bought the Furman, did not allow the noise through. It only happened shortly after I replaced the Adcom with the Furman. I just didn't put that together until after.

@lostbears okay, I read ya. Curious though because in any case fluorescent lighting can be a cause of DC on the line, and in particular if there are any dimmers involved. Also, it doesn't necessarily matter that any "offending DC item" be on the same breaker. DC and anything connected to the same panel is enough to permeate through your entire house. But if as you say you've isolated the issue to the Furman because you didn't have the problem with the Adcom, question then is does the Adcom provide DC filtering? You probably want to do something about the fluorescent lighting in any case. 

 gdhal, I don't know. I sold both the Adcom and Furman after I bought the Shunyata Triton. I also don't actually know how the Triton would fair in the situation. I threw away the light bulb when I found that was the problem. I did not want in the house after that. It seemed to be just one bulb out of the 4 in the fixture.

 I don't have any dimmers. And I have went out of my way to get rid of all compact fluorescent in the house. I also find it interesting that the preamp seems to be the only thing that was affected. There was no buzz in the kitchen radio right next to the dining room. The stereo is on the other side of the house from the dining room.

 But it actually turned out to be some what of a blessing in disguise. If the whole thing had not happened I would still have the Furman. The  Shunyata Triton has a much bigger positive impact on the sound. I am very glad I upgraded and it was a great excuse for the wife. Also it didn't cost me anything to get my Ref 5se checked out by ARC as it was still under warranty. Plus ARC said they did a few updates to it while it was there. My ARC dealer was really nice about it even when they did not find a problem. It was just really annoying at the time.