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 17 responses by cleeds

jea48
tomiiv30 needs to hire a Power Quality testing company to check the quality of the power in his home.
Agreed. And if the OP seeks a definitive assessment of the unit itself, he'll need to send it back to McIntosh or to an authorized service center for a complete evaluation. That's something his dealer - which he for some reason won't identify  - apparently isn't equipped to conduct. Simply plugging it in to see if it buzzes isn't the equivalent of a proper bench test.
jea48
Your are the one that seems to be having a problem believing the OP.
No, I don’t have any problem at all. Evidently the OP doesn’t have any problem, either:
I don’t need anymore help nor do I care about this brand anymore.
Case closed.
tomiiv30
 Are you out of your mind ... you are something else bud. People like you make the brand look even worse than what it is right now ... Why don't McIntosh come to my house and check out the problem, I have hiatal hernia and been diagnosed to not lift any heavy weights ... I still cannot understand how is it my responsibility to do all this things is beyond me ... I am left alone with nobody backing me up. I get back home all pissed off
... if some of you smart asses would like to prove me wrong than go ahead come to my house check out the amp and go from there.
I'm much more sympathetic to your plight than you understand. I hope you're able to get whatever help you need.
jea48
Ron, a McIntosh representative, said they get maybe 5 complaints a year about mechanical buzzing torids. His advice to fix the CUSTOMER’S PROBLEM is to buy a DC blocker.
You’re just repeating a claim made by an anonymous poster on Audiogon. We really don’t know if it’s true, or not.
Why do you have a problem with understanding McIntosh’s response to the customer?
I’m not the one with the problem here. I’m happy with my system and - for that matter - I’ve always been happy with McIntosh service.
So why do you continue to insist the OP send the amp to McIntosh?
I’m not insisting on  anything. But if the OP wants his amplifier evaluated, that would be a good first step.
jea48
You want to know so bad where the OP bought the amp why don’t you call the two dealers tomorrow ...
I don't care where he bought his amp. That the OP won't name the dealer just suggests that there's more to this issue than he's willing to acknowledge. In any event, it's all a moot point now that he says this:
I have made up my mind about this brand not just this amplifier ... The amp buzz has nothing to do with what I have done ... the experience I’ve had so far with this brand alone is unforgettable and was unpleasant. After spending so much money and not even one phone call was made back to me that should tell you something ...
He seems to want someone to rescue him from his misery, but he won't send the amplifier in for an evaluation. That just seems odd to me. If he doesn't trust the factory, there are many independent, authorized McIntosh service centers - perhaps even one within driving distance for him. But he has made up his mind, so there's really nothing else to talk about here.
jetter
Believe me we are with you in hoping this all get sorted out
Agreed! That's why I think this guy should return the amplifier to Mac for evaluation.
Why won’t  tomiiv return his amplifier to McIntosh for warranty repair?
Because it would cost me more money to do so, I have to pay for shipping both ways which is not cheap, and I am not planning to spend a cent more because I am pretty sure nothing would get done.
It looks like you’ve made up your mind to be unhappy, rather than to seek resolution.

It appears that the only money you’ve spent on this so far was for electrical work performed by an unqualified contractor that was hazardous and did not meet NEC.

tomiiv30
Why do you want to know so bad who the dealer is, I don't get it ...
You've stated that, "no one from the dealer or the manufacturer cared to find a solution to my problem," so it's reasonable to ask who the dealer is.
the manufacturer should've jumped in and try to help me
It still isn't clear why you don't simply return the amp to McIntosh for evaluation and (hopefully) repair.
tomiiv30
When the dealer and the manufacturer do not give a flying F about their customer ...
Who's the dealer?
what else can a customer do except keep the amp ...
You could return the amp to McIntosh for evaluation and (hopefully) repair.
I am no planning to repeat myself again everything is noted in this thread
Who's the dealer?
audioman58
That is total BS ... that is a defect in the unit period ... they should take the unit back and fix the dam
thing ... Their integrity is not what it used to be ...
I agree that there’s nonsense going on here - the facts just do not add up. The OP has deleted his original post here about the problems and disappeared from this forum and the other forum where he raised these issues. He won’t identify his dealer - even though the dealer doesn’t seem to have been very helpful in resolving the problem - and he has refused to return the unit to McIntosh for evaluation. So it’s really impossible to know what’s going on.
There transformers used to be made in California ...
They’ve always been hand-wound in Binghamton, afaik.
tomiiv30
... I just turned off the breaker for that outlet and would not use it until I find somebody that really knows what he does and to double check if everything ...
Why don't you get an electrical construction permit? That would probably resolve all of your concerns.
jea48
Chicago? I didn’t think the city of Chicago AHJ allowed NM sheathed cable ...
If this guy lives in Chicago, then the work he described would require an electrical construction permit from the city. It would also require that an electrical inspector approve the work before the circuit could be energized. While the permit may cost a few $$$, it would be cheap insurance against the sort of hazardous connections described here.
tomiiv30
What is the difference between the ground wire that is connected to the panel itself and the one that goes to the outside, it still goes thru the panel but it is not attached to the panel itself it just goes thru the pipe that goes outside where the meter is and from there it is attached to the rod.
All grounds must be bonded together along with the neutral at the service panel. Your separate ground creates a chance that a fault to ground won't trip a breaker. That's the biggest problem with the arrangement and why its an NEC violation.
The guy that came to my house and did this has been in business for over 30 years and I trust them thinking they know what they do
It's likely that your town requires a permit for this work. Did you check into that?
tomiiv30
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.
If you're in the U.S., that's a violation of the NEC and is potentially hazardous. It also creates a potential ground loop, which can only exacerbate your problems.
jea48
... why would you still want to buy a McIntosh product after hearing the way they have treated the OP?
Because we don’t know how McIntosh treated the OP - it’s just hearsay from an anonymous poster. On the other hand, I have years of first-hand experience with Mac.

Charlie Randall (top USA dog now) is already starting to make ARC equipment look like McIntosh
ARC doesn’t look at all like Mac - ARC has rack width; choice of silver or black finish; no blue meters or logo in a Gothic font ...

tomiiv30 
... even if it does I would still be not satisfied with this amp .
Why prolong your agony? Why not return it for a refund?
stereo5
3 members of the forum told me there was a bad batch of the potted transformers which was confirmed by McIntosh.
That certainly wasn't publicly posted in the forum. Are you saying that AA users told you that privately?