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
…….I just read this thread as I found it very interesting and informative and I have spoken with Mac dealers and there is pervasive air of arrogance about Mac products. Rightfully so but to a degree that if I were given a glass of Kool Aid I just may pass on it. I am looking at the new 462. Aball ncie to see you again and my only suggestion would be to try and get ; Clearthink to use punctuation…..wow, those sentences were a paragraph long !!!!
Hi garebear, nice to hear from you!

Hi chazzzy, ok well wish him good luck. It has now been 55 days and still no parts, and no emails in the last 2 weeks. To add insult to injury, I got an automatic reply from the Customer Service Manager just now saying that he’s out of the office until 8/10. Well, today is 8/22.... Unfortunately, I think that says it all.
Just thinking out of the bag here - if the choice of output transistor is questionable - and from what I read in this thread this is likely the case - is there a substitute available which does not suffer from this ailment? There is literally 100s of BJT,s designed for AF.

Best of Luck

Peter