MC240 Restoration

dingo1670

New Member
Hello Fellow McIntosh fanatics! I am currently working on Restoring my first MC240. I have already gone through the PS Section and am currently measuring all of the Carbon Comp resistors and Capacitors. There is some debate o whether to leave the Red Lettered .22uf 600V Black Beauties in or not. I am measuring mine and they're coming back at around 1uA of leakage @ 600V. What value is considered not acceptable?
I am being advise that given their age, I should replace them as the Caps are now over 55+ Years Old! I would replace with a combination of Orange Drops and Russian K40Y Capacitors. Thanks for your feedback in advance!
 
I think Terry DeWick leaves those in there iirc. He makes zero commission on the parts he doesn't sell you! : )
 
Terry afaik leaves the 160P as did I. I did not check them myself for leakage, taking the opinion of my predecessors.
 
Terry afaik leaves the 160P as did I. I did not check them myself for leakage, taking the opinion of my predecessors.
Well I do have 2 of these puppies to do, so maybe what I'll do is a little comparing. I'll change those particular caps on one unit and leave in on the other. I'll do some listening tests and see how different they sound. If the sound is comparable, I'll change them on both given the age of the caps. Eventually I'll be running these in Mono mode, so I want them to be close in sound for obvious reasons.
 
Sounds like a great plan. I wonder if 50+ year old caps sound like new or just different? Some folks say they like the "sound" of vintage components but I wonder what they are really hearing.

BillWojo
 
Well I do have 2 of these puppies to do, so maybe what I'll do is a little comparing. I'll change those particular caps on one unit and leave in on the other. I'll do some listening tests and see how different they sound. If the sound is comparable, I'll change them on both given the age of the caps. Eventually I'll be running these in Mono mode, so I want them to be close in sound for obvious reasons.

I'd like to hear your impressions .
Keep in mind if you go with the Jim McShane parts you'll have several Russian PIOs .
They take some time to break in.
You may want to wait a few dozen hours
(Perhaps a hundred or more)
Before you A B
 
Sounds like a great plan. I wonder if 50+ year old caps sound like new or just different? Some folks say they like the "sound" of vintage components but I wonder what they are really hearing.

BillWojo
I still have the original Good-All film caps in the 'direct' signal path of my Marantz 8, the high pass path caps are replacements. I don't listen thru the high pass. I really can't say about the total sound signature of the amp re the original caps vs replacement, but the measurable static state characteristics of those vs a "perfect" cap like a Teflon example can be determined.
 
I'd like to hear your impressions .
Keep in mind if you go with the Jim McShane parts you'll have several Russian PIOs .
They take some time to break in.
You may want to wait a few dozen hours
(Perhaps a hundred or more)
Before you A B
You're right, I think it would be better to let them settle in a bit before making a judgement call. Good call!
 
Sounds like a great plan. I wonder if 50+ year old caps sound like new or just different? Some folks say they like the "sound" of vintage components but I wonder what they are really hearing.

BillWojo
I was wondering the same thing and so have others I guess. Did the Amp sound like it does when it was only a couple of years old?? Or do the aging of the components somehow change the sound signature to our liking?? That's a tough one!
 
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I was wondering the same thing and so have others I guess. Did the Amp sound like it does when it was only a couple of years old?? Or do the aging of the components somehow change the sound signature to our liking?? That's a tough one!
Assume we are saying for component parts that hold measured value but are aged under working cdx.
 
Well I do have 2 of these puppies to do, so maybe what I'll do is a little comparing. I'll change those particular caps on one unit and leave in on the other. I'll do some listening tests and see how different they sound. If the sound is comparable, I'll change them on both given the age of the caps. Eventually I'll be running these in Mono mode, so I want them to be close in sound for obvious reasons.

I have a pair I run in mono with the original 160P caps in them. I left them in based on Terry D's statement that they're rarely bad. Well, since I got a real cap tester, I've tested many other 160Ps and almost all leak to various degrees. I intend to change mine for K40Y.
 
I wonder if they may be "ageing out" years after Terry made the determination. The problem would be with the leakage shifting the operation points of the various stages in which they are used.
 
I have a pair I run in mono with the original 160P caps in them. I left them in based on Terry D's statement that they're rarely bad. Well, since I got a real cap tester, I've tested many other 160Ps and almost all leak to various degrees. I intend to change mine for K40Y.
Just picked up some 40Y’s and tested them all for leakage even though they were never used. They all had some, but what I would consider very minimal and accaptable
 
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I have a pair I run in mono with the original 160P caps in them. I left them in based on Terry D's statement that they're rarely bad. Well, since I got a real cap tester, I've tested many other 160Ps and almost all leak to various degrees. I intend to change mine for K40Y.
Well I’ve successfully completed my complete Re-Cap and Resistor changes on both of my MC240’s. I replaced the Caps with K40Y’s. It really wasn’t bad at all. I tested everything as I went along. During my restoration I picked up a very nice MX110Z, and so this evening I was completely blown away by this marriage! I believe I have found the Audio Nirvana I have been in search of for so long. I mean WOW!!! It’s simply incredible with what I am hearing with these MC240’s and the MX110Z. Glorious
 
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