DC Offset Blocker/Killer - where to buy in the USA

   I have McIntosh MC8207, the first unit I bought from an authorized dealer came with a loud buzzing coming from the left transformer, and was replaced with a new unit which came with even a louder buzzing. The buzzing can be heard from 8 feet away. Then I was told to have install new 20 amp outlet that has its own isolated grounding.
   That was done professionally by an electrician who installed two isolated 20 amp outlets, two 20 amp circuit breakers, two copper polls for grounding for each outlet, each outlet has its own neutral and power line. After all this done the buzzing sound was still there.
   I was then told to buy a power conditioner which I did (Audio Quest Niagara) which was like $4000 and that did not help. Called back McIntosh and was told that I might have DC offset in my AC line and was told by McIntosh that I would need a DC Offset Blocker/Killer to which when I asked them where to buy one they told me to go on the internet and search to find one, to which I cannot find one.
  This bothers me a little bit, if you as a company think that I have dc in my ac and i need a dc blocker wouldn't you need to sell one as well. I brought this amp to my friends house and it was the same no improvement, so my guess is that he has dc in the ac line as well.
   So If anyone of you knows where to buy a DC Offset Blocker/killer please let me know, but even if this helps kill the buzzing wouldn't you guys think that this expensive somewhat hifi amp/brand should be silent from the factory. I mean this is two units in a row all purchased brand new.

My house is 5 years old, everything is brand new, the whole neighborhood is about 8-9 years old, my electrician says that I have perfect power coming to the house and everything looks fine.

Thank You

P.S. to my previous post: I didn’t mention the units that should be used for R and C in the various calculations. If R is expressed in ohms and C is expressed in Farads, the calculation described in my last paragraph will provide an answer expressed in seconds, and the calculation of bandwidth that is described earlier in the post will provide an answer expressed in Hz.

-- Al

I am curious how the OP made out.  I believe he was going to the dealer earlier this week to get it sorted out.  I hope he sees this and replies.
Here is the update and it’s a surprising one:

Went to the dealer today with the MC8207 and right away I was taken upstairs to their tech department where they plugged this amp and the result was a dead quite none buzzing transformer and I mean dead quite not even a small buzz. Now I don’t know if their outlets have been treated since this is the tech department and not any other place in the store, it was the only place that we tested it. I was very surprised and happy at the same time knowing that this amp can be quite so I guess it leads me back to my house or the outside power.

I am in a search of somebody that really knows how to measure DC offset in the AC lines, I did what McIntosh told me to do and it returned 0.9mV which is nothing to make the transformer buzz but it could've been a wrong measurement.

As for the LED Lights that were not illuminating equal Left Side to Center to Right, there was a slight shift of an inside part that the tech had to open the front and fix it to make it all Illuminate the same, bear in mind this is a brand new amp and it needed to be open to be fixed.

I have already spoken to my electrician who is coming back to the house to do an extensive checking and we would be unplugging everything from the outlets and I mean everything, and will be turning off all the breakers off except the one for the amp and see if we can finally find the problem and if that doesn’t help than it would be the right time to call the electric company to do their part, because otherwise it would be very hard to convince them to come out just because I have a buzz.

I am a person that do not give up and would like to find a solution to fix this problem no matter what it takes as long as it is fixable.

And if anyone from here ever had to deal with their electric company would you be kind to share the steps taken to convince them to come out.
I wanted to upgrade my service from 100 amps to 200 amps.  Was told by electrician I had to contact the electric company to have the wire from the pole to my house upgraded that will carry 200 amps.   The electric company came out to evaluate.  I got a letter a few days later saying that I could safely go up to 150 amps but they won’t change the drop wire as there isn’t enough “electricity” for 200 amps.  I took a picture of the pole across from my house where the hook up goes and lo and behold there is a big transformer on the pole. After i appealed the letter and they realized there was a transformer there, I got my way.  I went through hell and this took 6 months for the permit to be issued.  

These are the things I was afraid of, going through all the hoops and troubles, time, costs for what, to fix a problem that could be easily fixed IMHO by the manufacturer.