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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
jea48
4,822 posts
 
@ tomiiv30 OP

Your branch circuit wiring is more than likely installed in EMT (Electrical Metallic Tubing).
https://www.homedepot.com/p/1-2-in-x-10-ft-Electric-Metallic-Tube-EMT-Conduit-853428/100400405

Per the NEC the EMT conduit is considered an equipment grounding conductor, Not sure if Chicago AHJ does though. I would imagine they do. Therefore per NEC the steel outlet box and supporting back strap of the IG duplex receptacle is grounded.

Now I talked to another electrician just now and he said to me that the way green wire is done it is probably not up to code but he said that even they (then) it is should not be a problem.

Stop!
Find another electrician! Keep looking.

This guy sits on one of the NEC (National Electrical Code) boards that helps write electrical safety code.
Watch the video.
https://www.youtube.com/watch?time_continue=2&v=qNZC782SzAQ

Now what did the electrician tell you over the phone again?

I know Chicago has good electricians.

Jim

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tomiiv30 OP
65 posts
 
@jea48

Man, that was an eye opening video. Now let me tell you something, I was told to do the copper rod by many of this or other forums to do what I have done and think that is the right way and that it should work.

After watching the video it explained very well how everything should be done and I don’t think lot of electricians know this let alone audiophiles that thin they know but they know nothing. He also mentioned us the audio guys are doing extra rods to get isolated grounding.

stereo5's avatar
stereo5
6,582 posts
 
@tomiiv30...……………………..

McIntosh winds all their transformers in house.  Don't let anyone tell you different.  I toured the factory and watched the person doing it.  This person has been doing it for over 40 years at McIntosh.
tomiiv30 OP
65 posts
 
@stereo5 

Yeah but that doesn't mean that they don't use somebody else to do the transformers for the less expensive amps like mine.
There is another one or two threads on Audiokarma with the same problem as mine.
I mean this lady is getting old and is the only one at the factory as far as I know and how much more can she do - right?
gdnrbob
4,510 posts
 
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
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