2. amps-preamps
  3. 136143-1060

McIntosh (MC601) amplifier overheating problem

Hello everyone - A buddy of mine has MC601s that have recently started overheating.  Each amp went into protection mode after emitting a burning smell, and both had to have an output transistor replaced (at different times).  

My internet digging has revealed that ThermalTrak transistors are not very reliable, or at least the early batches were not.  Ayre has also reported overheated MX-R amps with the same problem.  They apparently can fail after years of use, which is not good news for owners!

I'm trying to get a feel for how widespread this problem may be (at this point in time)?  Each transistor replacement is $400, and there's an awful lot of output transistors in MC601s...!!  I convinced my brother to also get MC601s so I'm starting to get really worried his will fail too in the near future.

So far, McIntosh's response to my inquiry has been vague and reticent, unlike Ayre who apparently went to great lengths to remedy this issue for their owners.  Has anyone out there had this problem with McIntosh or Ayre?  

aball
clearthink
1,421 posts
 
It sounds to me that your friends amplifier's are not being properly repaired these amplifiers are legendary for they're reliability you should suggest to your friend that he seek, identify and secure the services of a factory authorizied technician to examine his amplifiers. 
aball OP
2,016 posts
 
They were repaired at a factory service center.  I know exactly what the problem is.  Thanks
clearthink
1,421 posts
 

aball"They were repaired at a factory service center. I know exactly what the problem is."

It is evident that you are not sure of what the problem is and that is why you are posting hear I am sorry I did not mean to embarass you if the amplifier’s were serviced by a factory authorized service center then they provided a waranty along with the service you should return the amplifier’s to them for the additional service that they require or otherwise see another authorized service center because this on that you used is clearly not capable of properly servicing these amplifier’s.
clearthink
1,421 posts
 
It also should not cost $400 to replace each transistor that is ridiculous and an indication to all that the service center is not what it may appear to your friend to be. 
aball OP
2,016 posts
 
Ok, now I remember why I quit posting here years ago.  

I am an electrical engineer.  I read the repair order.  I design amplifiers.  The issue is bad output transistors.  They have repaired it twice by replacing them twice.  But there are like 4 dozen transistors in each amp.  Chuck Hinton recommended the service center to me.  Now can you please go away.  Thank you.
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