2. amps-preamps
  3. 142371-120446

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
4,560 posts
 
@ tomiiv30 OP

How about an update on your electrical. Did the electrician come out and check for possible electrical problems in your home?

Possibly loose and or corroded wire connections in the electrical service panel?

Have you spoken to any one yet from your utility power company?

Jim


tomiiv30 OP
65 posts
 
Yeah he came to the house checked everything again and he said not to call him any more, he thinks that I am bulls^&#g with him, and that's why I did not write anything about it. I feel like I have been let down, like I said this were the worse $30K spent in my life. 

Talking to the electrical company is like talking to my 5 year old. I just don't have the nerves and time anymore and would just live with it, I got so tired of this whole situation that I gave up.
jea48
4,560 posts
 
Yeah he came to the house checked everything again and he said not to call him any more, he thinks that I am bulls^&#g with him, and that's why I did not write anything about it.
What did you find out about how the electrician wired the two ground rods to the two new wall outlets for the two new dedicated branch circuits you had him install?
tomiiv30 OP
65 posts
 
It is one rod that he installed in the ground that is few feet away from the outside meter/box, the other rod was installed form the electrical company, it was already there, that's why I thought he did 2.

One of the 20 amp outlet is grounded to the inside of the panel.

The other 20 amp outlet is grounded directly from the outlet to the outside rod with a clamp that is attached to the rod itself, I saw that with my own eyes. It is a straight wire that goes from the outlet to the outside and has nothing to do with the inside panel or anything else in the house.

Both these outlets are on it's own there are not shared with any other outlets in the house.

He did measure few different things he would not let me tell him anything he just said everything measures fine. I know I saw him measuring on the panel where he got 240 volts and said one is 120 and the other is 120 something in those lines. He measured the outlets too, I don't know what he was doing but after he was done he said that to him everything looks good and he said good like convincing the electrical company to come out.

That's all I have. And I am not planning to spend any more time nor money to call other electricians or whatnot.
glennewdick's avatar
glennewdick
1,731 posts
 

I did not read the whole thread so sorry if this was addressed. doesn't  Mac use transformers for coupling? so maybe there is only one power transformer that's why only one is humming. The others could be for coupling.


More to discover