Amp "Hum" caused by dimmer switches

Before you give up, you should try the AudioPrism Quiet line filters. They look like battery eliminators for a CD player, often referred to as a wall wart.

Many household appliances (and especially dimmer switches) dump loads of noise into your electrical system. Even when the problem is not as obvious as in your situation, this noise creeps into every component in your sound system and effects performance. I had a totally quiet system, and bought a set of Quiet Lines at CES just for the experience. After having them in my system for a week, I removed them, thinking I could do just as well without. That idea lasted just about to the end of the next piece of music, whereupon I replace them and they have remained ever since.

These filters are inexpensive, and can be moved from one AC outlet to another, to determine the best results. They come in a pack of 8 pieces at retail $300.00. You should be able to find a dealer that would let you try a set over one weekend to see if they fix your problem. If they do, this would be less expensive than reselling and shipping the amp that you are otherwise happy with.

Albert- Are you using a line conditioner with the Quiet
Lines? I'm having a hum problem with my amp and I have a conditioner and dedicated line. I put the amp in my second system and no hum, so it's not the amp.The hum is local in the amp and goes to the speakers. Any ideas??

Try installing a better quality dimmer - some of the "better" ones have RFI filtration caps. etc. so they output less radiated noise back onto the AC lines. I had this same problem for years, & didn't discover the source until that old round-knob dimmer finally failed & was replaced. The new one is a toggle switch type, but price was comparable BTW. Also I have seen little filters available that you can install across the AC line input & line output. I don't know the manufacturer, but someone here probably does? It appeared to be a quality cap. & a series resistor package, something like 0.1uF in series with 47 ohms?

Also try an AC line conditioner - borrow one from a local dealer for audition. A Chang Lightspeed 3200 or etc. is not that expensive, cheap if bought used & resellable if no help.

I second the recommendation to upgrade your dimmer. Lutron makes a number of high quality wall box installable dimmers. I use 11 of their Diva Series units in my home. Even when they are all on, no hum. Other problematic items are diode (capslite) bulbs, anything with a high/low switch that uses a diode (will drive class b amps (usually subwoofer) crazy).

Another suggestions would be to use a different line to supply the audio system (or dimmer). Best would be a seperate dedicated audio line. Use a very low wattage bulb with no dimmer. Or if you want the ultimate no noise dimmer, replace the dimmer with a variac (variable autotransformer). They don't install cheap, but are silent.