Audible Buzz from Lexicon: dimmers & microwave?

Thanks for this Dave. Really great info. I'm wondering if anyone else has a way to deal with this at the panel and isolate my A/V gear?? Jea, this is a good link but I'm not an electrician and not sure what this means in practical terms. I've had electricians come in with no real luck here. Polarity and phase are fine, voltage registers fine, the outlet is a Shunyata and is fine, the circuit is a dedicated 20 amp and it's fine. The neutral is fine. They also moved the circuit from the sub panel to the main panel. No luck. One thing that gets the buzzing on the lexicon amp's transformer is the microwave oven's stove lights (it's over the stove and has a hood light). If it's on "low" the buzzing from the Lexicon is VERY loud (again only from the chassis). The kitchen dimmers also appear to (sometimes) impact the loudness of the transformer buzz. I ordered the PS Audio Hum Buster III from Music Direct in Chicago (Mark there was FANTASTIC). WE'll see how that goes. Now, is there ANY WAY AT ALL to check for DC offset? The electricians plugged in their meter and DC registered as "0" but they were perplexed at the notion that DC could be on the AC lines. I printed out forum threads, etc. but they really didn't know how to do anything different. Thanks all.

One more question here.... is there anything specific in terms of tests or meters, etc. that I can tell the electrician. It's obvious that the electricians are not used to seeing a high end home theater/music setup and are really baffled by this. Much appreciated!

Thanks for the responses all!! On Monday I ordered the PS Audio Hum Buster III. Sorry Gbart!!! It's scheduled to arrive today, so we'll see how that goes. My personal preference is to obviously deal with this at the electrical level. I have stopped using the microwave lights (though that can't be helped if you want to cook on the stove top and need light :-) Responding to Jea, we do have low voltage lighting (the house was built in the 50's) along with "traditional" switches. All the dimmers are Leviton in the kitchen and elsewhere. The only exception is I had three dimmers replaced with Leutron this past week too (don't remember the name for their slider 3-way). I also noticed that I have an older TrippLight surge protector and it too buzzes when plugged in. It's pretty loud from the TrippLight.

I have a completely different electrician coming the week after next to the house. I'm hoping he can find *something* because this is obviously a problem I'm having everywhere in the house and I'd like to get it addressed and find the source. When I spoke to him, he too was baffled as to how to track this down.

Oh! I also had the microwave electrical outlet checked. It came out fine and even with the microwave itself completely unplugged it was STILL buzzing!

Jea, that other quote from Nelson was a good one. I had come across it and printed it out (along with other forum threads) and gave them to the electricians. They are all really baffled. This is not something that they deal with and one guy who has had 15 years experience shrugged and said this is the first time I've come across this.

I'm going to print out that Westhost.com note about testing for DC across the mains too. I hadn't come across that one in my research! Thanks.

I am **so appreciative** for everyone's responses and help here. This is the first time I've come across something like this and as only we audiophiles can truly understand, not being able to use my system properly is just driving me bonkers. I can't wait to finally get a solution here and enjoy my system once again :-)

Jea, specifically to the type of lights on the dimmers, they are regular incandescent lights. They vary in wattage but are mostly the 65watt recessed lights.

Well I unpacked the PS Audio Humbuster III animi absolutely stunned. Literally stunned. No noise at all from the Lexicon amplifier. I even put on the microwave and no buzzing at all. Dead silence. I then took the hum buster out and bang the buzz came back. Put the hum buster back in and the buzz is gone. I cannot believe the audible difference too. Played some concierto de aranjuez, more detail and openness and smoothness and finesse. Followed that with some female rock vocals. Pat Benatar and Sarah McLaughlan and plain old HDTV. I haven't tested dynamics or an A/B with the same piece of music yet. I am sitting here stunned with how the DC current was affecting my system. I'll still see what I can do at the source level but for now I'm a believer in the hum buster and removing DC current from the power lines.