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

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.
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. 
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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If $400 is the total price and not per transistor, then that is not unreasonable.  $400 per transistor is stupid.  

However, if the tech tested the unit, took it apart and found only one failed output transistor, understand that he/she had to test each one on the side (right or left) that failed, replace it, put the unit back together, test it, package it then yes, $400 isn’t unreasonable. 

Say you you have a stereo amp with push/pull outputs and one side failed.  Most new amps have protection circuitry so the entire amp shuts off and I don’t know which side had the problem.  So I have to disconnect each side separately from the power supply to see which works and which doesn’t.  Now that I know which failed.  There are a few ways to test transistors in circuit.  Non are as accurate as removing each one, testing it and replace the bad ones.  I also have to test the pre drivers because an output driver failing sometimes fails pre drivers. 

My point is that is a lot of work and testing.  If the end result is only one transistor failed (unlikely), it still was a lot of work. Say 2-3 hours labor and if the amp was constructed like a mark Levinson 23.5, then it’s more. Very hard to take apart and remove transistors.  $400 not unreasonable 
I started by saying it was unreasonable and then thought it through.
What’s the latest on this aball?
McIntosh has gone silent in my attempts to get them to help!  

Ayre took back their amps, and even sent out an RMA for shipping them back (Charlie posted in another forum about it), whether they were under warranty or not.  But McIntosh apparently doesn't care about their customers anymore.  It's so unfortunate.  It seems my friend will be on the hook for having all the output transistors replaced on his dime, despite the fact McIntosh sold defective amplifiers.  I'm guessing it'll cost him $1500, maybe $2000, plus shipping.  It's a big job.  My brother and I also have ThermalTrak amps...I hope they will be ok.

aball
"
McIntosh has gone silent in my attempts to get them to help!"

I find this very hard to believe something does not sound right here not only does McIntosh make some the finest, best sounding and most reliable amplifiers in the world but they also provide first class service and attention through there many many dealers and distributors in their vast distribution network so you're experience hear tells me that you are not providing all of the information regarding your circumstances perhaps these amplifiers have been previously improperly repaired, modified or abused.  
Good grief, you again.  If you have doubts about my understanding of McIntosh, I suggest you read the 1000+ posts of mine from 15 years ago.  Until then, stop your useless assumptions.

What I am presenting here is reality.  As I've already stated, the service center was recommended by Chuck Hinton (apparently you don't know that he is the McIntosh tech support manager).  I am currently waiting to hear back from the service manager, who I hope will be helpful.  


aball"If you have doubts about my understanding of McIntosh, I suggest you read the 1000+ posts of mine from 15 years ago. Until then, stop your useless assumptions.What I am presenting here is reality.

I am not interested in reading your 1000 posts that are 15 years old I do not believe that as you said McIntosh has gone silent in responding to your problem because that is not how this excellent company treats it's customers and now you say you are "waiting" to hear back so what you are presenting here is inconsistent self contradictory and frankly nonsensical.
Emails between me and McIntosh are obviously still ongoing. Now please go away, again.

The point of the post was to ask if anyone else has had an overheating problem yet. Thanks to any who can offer relevant input.
aball"Emails between me and McIntosh are obviously still ongoing. Now please go away, again."

I am not going to go away bullys like you are common on any kind of forum and that includes those dedicated to Music Reproduction Systems and on top of that you seem to be confused or perhaps intoxicated how can it possibly be obvious that "obviously" you are still in touch with McIntosh when just before that you wrote -

"McIntosh has gone silent in my attempts to get them to help!"

You have attempted hear to portray McIntosh in a very unfavorable light and have tried to make the case that these amplifiers and their specially selected transisters are somehow defective when I think if you have a McIntosh amplifier(s) at all you have had it improperly repaired previously or another possibility is that you bought it used and the previous owner(s) had it improperly repaired or abused it in some way.

I think you are a winkly dinkler and if you still want me to go away that is going to be your problem I have every right to be here even though I am not a US citizen.
Clearthink - your input is still not relevant.

Any McIntosh owners out there with overheating amplifiers?  Thanks
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the only MC amp i have at moment runs 6L6 output devices.... however i can attest that Ayre did handle failures with grace  - I had a VX-R that the thermal tracs failed in one channel, lucked nto help with Twenty series upgrade at that time which use different output devices....
good luck
hope MC helps you i still run a bit of kit from them...
Sorry for your issues. I have had several McIntosh units over the last 30 years. None have ever failed. I have had a pair of 601's for awhile now driving Revel Salon 2's. They have been perfect even after listening to The Who at concert levels for extended periods of time. As far as questions about equipment, McIntosh has always been very helpful and prompt with their responses. Just my experience. 
I had the same overheating problem with a mc-352.  I have two and run them mono. I bought both used. The unit in question would overheat then shut down.  Then after a few would come back on. While the other would not have any problems with the same input. Eventually the unit made a Burning smell and shutdown for good.
Took the bad unit to a authorized service center in royal oak Michigan. They went through it found what they thought was wrong and reassembled. They then wanted to make sure that they had solved the problem, so they ran the unit for a few days on their bench, and the same problem occurred. It fried again. They went back in and replaced a whole side of output transistors. (I saw the bag of transistors they replaced, it was a bunch).
 The whole process of th repair took almost 6 weeks (evaluation, ordering parts, labor, testing, evaluation, ordering parts, labor, testing). In the end the bill was $650.00.

So with the repair cost of $650.00 and the $2700.00 I spent on the unit I have $3350.00 into a mc-352. It’s not the greatest deal I ever made, but I wouldn’t say that I am unhappy with my purchase. 
$2,700 for an MC352 is a great price.  Even at $3,350 it's a solid price.
Thanks guys for the feedback. 

Yes, Ayre did a great job taking care of this problem.  Wonderful customer service.  I am in the market for a VXR Twenty as a result!

I've had 21 pieces of McIntosh and never had a problem, other than a cosmetic issue with my MC152 front panel.  But my buddy is hurting.

I will keep you posted on what McIntosh decides to do. 
Hey aball good to see you again.  I’m not round here as much anymore either.   Good luck with Mac.  Don’t want to jinx myself but my 501’s have been driving Thiels for years and haven’t broken a sweat yet.  Hope there is an easy solve.  
Hey Jerry!  Great to hear from you.  I probably won't become a regular again (it seems little has changed around here lol) but it's nice to hear from you and the others that have messaged me directly.

The 501s have different output devices, so you don't have to worry.  On Semi is on their third version of the ThermalTrak BJTs now (they are aware that their early ones had design flaws) so people with later 601/452/7000/152/302/1201 etc. are probably fine too.  I just hope my brother's 601s will be ok, even though serial numbers suggest otherwise.
Arthur
McIntosh has finally arrived at a decision, after a month of back-and-forth, and it isn’t nearly as good as Ayre’s unconditional warranty for the same issue: they will only pay for parts in the form of built-up heatsinks. My buddy feels this is an ok solution, but it will probably still cost him $400 in labor, plus shipping. It’s a shame - their literature says their amps "last a lifetime" but then they don’t stand by them like Ayre does. Apparently McIntosh isn’t quite what they used to be. Oh well, that’s the way it is, lesson learned, moving on.

If your McIntosh amps overheat in the near future, I hope they will accord you the same offer, but you might have to fight for it as I did.  I wish you all the best in that endeavor. 
I had issues with McIntosh a few years ago with warranty.I will never buy their products again.Their customer service reps on the phone were as rude as it gets.
you probably have a lemon. good luck.
Wow Arthur, sorry they busted chops!  Not matter how big your only as good as your last customer.  Senior management at Mac would do well to better remember that.  Business can be fickle.  
don’t leave because of one bad apple.....on balance the rest of us on this thread try to help

i can say VX-R twenty very special amp......bit of a beast to lift, it is hyper dense....

i replaced it with purpose built monoblocks designed to only drive tge speakers I have....but i can say it is one sweet sounding SS amp....

good luck  
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did your buddy buy these new? how long has he had them? are they still under warrenty? take it back to where he bought them. if he bought it from a private party, good luck!
He bought them new from a McIntosh dealer, but they are out of warranty by 2.5 years. However, Ayre didn’t care if they were under warranty or not - they repaired them all regardless. In fact, there is a thread about all this on another forum where Ayre themselves posted and said so! Great customer service from Ayre because they realize the amps were defective in manufacturing.

I’ve been a McIntosh owner for the last 20 years. I still love mine (I have 6 Mc pieces right now). I am just disappointed that McIntosh was not willing to do what Ayre did. It’s a bummer. I saw them fully as equals until now. I just hope that my lovely MC152 and my brother’s MC601s won’t develop the same problem...!
kind of strange that both units are over heating.
Hi g_nakamoto,  it's normal that both are overheating because they both have bad transistors in them.  The ThermalTrak transistors are the problem (which were made by On Semi, not McIntosh).  Going by the amp serial numbers, there appears to be hundreds of amplifiers with bad transistors in them, so we won't be the only ones with this problem.  We just happen to have experienced it, and, said something here about it.  Unfortunately, only a tiny percentage of McIntosh owners are active in the forums.

While I'm at it, a quick update:  McIntosh told me they would have the built heatsink/transistor assemblies made for us in 25-40 days.  It has now been 40 days and I haven't heard anything, so I sent them an email just now asking for an update.  Fingers crossed they at least come through with this.  Stay tuned.
I was thinking about buying 601 used in the near future. Looks like I need to by 611 instead? Better to save more money now!
…….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 !!!!
A friend of mine has the exact same problem with his Mac stereo amp. 
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 
Arthur, thanks for the update, however not the good news I was hoping for being a Mac owner.   Best of luck and kick their a$$!
Ok!  McIntosh finally came through.  Unfortunately, they did not want to swap the amps out for us (as Ayre has done for the exact same problem and situation), but they did send us 4 complete heatsink assemblies that are fully-populated and tested, ready to be installed in both monoblocks.  I have performed the swap for the latest faulty amplifier, and it wasn't very difficult, although it does require the amplifier to be on its side, which is a dicey proposition.  

We feel this is a satisfactory solution.  It took 120 days all said and done to get the parts.  Not impressed.  Good thing we have spare amplifiers laying around.  But, we are very happy they helped us out!

Now, fingers crossed that my brother's MC601s don't overheat...or anyone else's for that matter.
Same issue I had. Under warranty thank God.  Got them back and dumped them  as fast I could . Same issue with a MC8207. 
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+1 Elizabeth, sounds like a case of arrogance to me.  Hopefully issues such as this will reach more mainstream social media and force them to address customer service and QC. 

Glad you found a solve Arthur.....
Hi Sandy - Yikes!  I think this issue is even more widespread than it seems.  That's the nature of this kind of problem.

The unfortunate part about it is that, fundamentally, this is not a problem McIntosh had any control over - the transistors are not made by McIntosh, they are made by ON Semi.  I tried to explain to Mc that they should get ON Semi involved in this solution, since they made the parts.  Maybe they would be willing to pay enough to make Mc a solid business case for an "amp swap" instead.  Besides, they could upsell some people to new amps in the process.   This is how I would have handled it, had I been in their shoes.

I know a service center and a dealer that both say Mc is a pain to deal with.  I got to witness this first hand.  At these price levels, I was expecting them to want us to feel impressed.  That did not happen.  In this day and age, you cannot afford as a hi-fi business to act this way towards your customers.  The pond is too little.  

This notion has been reinforced by recent interactions I've had with Avantgarde Acoustic of Germany, makers of horn speakers.  I also know a couple people that have dealt with warranty repairs with AG, and I have to say they offer exemplary customer service. They go out of their way to make sure everything is perfect. It stands in such stark contrast to how Mc chose to handle a similar case.  

I was an advocate for Mc years ago in this very forum, back when it was not popular to come to Mc's defense.  But Mc has sort of been tossed around between large conglomerates for some time now, and it's hard to say how things are really going in there.  From out here, the core doesn't look too healthy.  It's a bummer.  Although I think it's totally fixable if they act now.

For the sake of balance, this brings me to some positive attributes I ascribe to McIntosh.  For one, I'm in love with my MC152 power amp.  It's fantastic.  It is a perfect balance of all things:  detailed yet coherent, beefy yet deft, sparkly yet sultry, here yet there.  Same goes for my dynamic MCD301 that I've just had refreshed at a Mc service center, who by the way did a great job, and was very friendly and engaging in the process.  So there is hope. 

Thanks for the replies, and have a great Thanksgiving!
Arthur