MC8207 Transformer Buzzing

[stereo_5]

I am asking this for an Audiogon member who is having a hard time with this amp. He bought from a reputable authorized dealer and the left power transformer buzzes so loud he can hear it from his listening chair 10 feet away. He returned the unit for another amp and it has the same problem. He contacted McIntosh service on 3 different occasions. They first told him he needs dedicated lines so he had a licensed electrician do that, having 2 lines installed both with separate grounds, but no change. Then service told him to buy a power conditioner and he bought an Audioquest Niagra to the tune of 5 grand and still no change. The last time factory service told him he needs a DC Offset Blocker.

It seems to me they are taking stabs in the dark. He brought both amps to his friends house 10 miles away and the same problem, the left toroidal transformer buzzes. His house is new, only 5 years old with a 200 amp service. He is quite ticked to say the least. I feel bad for the guy and I am trying to help him out. Anyone??

[krustycat]

Does it buzz until it’s warmed up or constantly?

[Cohibaman]

Sounds like a batch of transformers that weren’t potted properly. They pull them off the shelf as needed and he got unlucky twice.

[PMCH]

I had a similar problem with 2 new MC205's. Not sure if it was the transformer but I buzzing sound came out of the rear left side of both of them. I got fed up and switched to a MC8207 and it has been dead quiet since the day I got it. Strange, maybe there was a bad batch of transformers that went out. I would have him bring it back and get another new one.

[LarsT]

Ouch! Can he get a loaner from the dealer to hopefully prove it is the amp that is defective and not the electrical in the house? If that works, send videos to McIntosh. I have found videos work well. And if it is a second bad amp, I would be seeking some relief from McIntosh. That’s expensive and frustrating...an ugly combination

[stereo_5]

It buzzes constantly, warm or cold. I'm wondering why McIntosh is insisting it isn't a problem on their end?

[Poppyhome]

Originally Posted by stereo_5

............The last time factory service told him he needs a DC Offset Blocker.....

Yes, DC Offset is a strong possibility of the cause. Ivan mentioned this solution a few times and this product really works, and I ended up buying two and now have zero buzz

Emotiva CMX-2
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

You can also buy direct from Emotiva, but it looks like all is sold out until January 21, 2019.

Ron

[Masterlu]

Originally Posted by Poppyhome

Yes, DC Offset is a strong possibility of the cause. Ivan mentioned this solution a few times and this product really works, and I ended up buying two and now have zero buzz

Emotiva CMX-2
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

You can also buy direct from Emotiva, but it looks like all is sold out until January 21, 2019.

Ron

Yup, I always try to keep them in stock. A great unit for a specific problem.

[TomIV]

Hi guys,

I am the one with the problem that @stereo_5 posted or made this thread for me, I forgot that I had an account here.

So the problem that I am having is why do I have to buy a DC blocker to block the buzz, isn't this going to be masking the problem if the transformer is bad, have you ever thought of this?

Second of all, when you buy this expensive amp wouldn't you be thinking that when you get it home all you should do is plug it in and listen to the music or movies.

Third, if I have a DC in my AC why only one of the transformers buzz why not the other one? I am really confused and electrician is even more confused than me trying to solve a problem that could not be solved due to a bad transformer. He was laughing his arse off when I told him how much I paid for it.

[TomIV]

Originally Posted by Poppyhome

Yes, DC Offset is a strong possibility of the cause. Ivan mentioned this solution a few times and this product really works, and I ended up buying two and now have zero buzz

Emotiva CMX-2
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

You can also buy direct from Emotiva, but it looks like all is sold out until January 21, 2019.

Ron

Don't you think that having a DC Blocker is going to be masking the problem, I was told by a company that makes isolation products that this kind of mechanical buzz is only from a bad transformer and having a DC blocker would just mask the problem and not fix a bad transformer.