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

tomiiv30

Showing 12 responses by gdnrbob

I don't know much about McIntosh, but always thought they had a great reputation.
What you are describing isn't something that should be happening.
You have done everything correctly, and the issue persists, so it would seem the problem is equipment related.
The only other cause would be the power coming into your house.
Do you live in a rural area, or use your own power source?
Second, if you bought from a dealer, he/she should be by your side getting this rectified. Period.
I hate it when good people get the run around.
B
@tomiiv, 
Good Move.
There are plenty of great amplifier designers out there that you can choose from.
Especially at that price point.
Bob
@twoleftears ,
Exactly.
I bought a 2016 TTS that has a B&O sound system. 
It sounds like crap. My previous TTS had a Bose system that sounded leaps and bounds above the B&O-and that is saying something.
B&O had some really interesting gear in the day, but now that they have been acquired by another company, they are just resting on the name recognition.
Too bad for me, Audi trusted them- but, hey, it all comes down to money.
B
@jea48 ,
Would you recommend getting a DC blocker for every system?
I know not all lines have DC, but just as a precaution?
Bob
@tomiiv, 
I agree. 
For the electronically inclined, it is a walk in the park. But, those of us with limited skills (well, I can solder pretty well), seeing the list of items needed and putting them in the proper order makes me a bit uneasy. Mostly because I don't want to get fried.

Bob
@OP,
I think you have done everything you possibly could have to resolve the problem. I'm glad the dealer is refunding your money, but I think they should have been more active in resolving the issue. Especially having you install wiring, though a good thing in the end, should not have been something you had to do.
Hopefully, you can find another amp to your liking. 
Bob
@OP,
I would find another electrician.
From what you have described, I would be wary of what the original electrician did-especially with his nasty attitude, and concerned that this setup is according to code. 
Perhaps the whole problem with the Mac was a blessing in disguise. You might have uncovered a problem that could have become a Big Problem, if a lightning storm struck.
Bob
Wow, what a clam bake this turned into...
@tomiiv,
If your dealer's wiring doesn't produce hum in your amps, I don't see why he didn't have his 'electricians' check your wiring.
But, considering how you have been treated, I would be circumspect about asking them to look at your wiring.
There must be a listing of Master Electricians locally. And, one who has experience in home stereo wiring.
Bob
Are there any repairmen who specialize in Mac's?
I can see the OP's reluctance to send into McIntosh, all they are going to do is open the box and slap a label on it saying it is okay.
Though it would cost some money having someone look at it, at least you know if it, indeed, has a problem. And, using that information tell McIntosh. Who knows? They might find the issue and repair it.
B