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Levinson 20.5 monos - Time for a Refurb?

I bought my Mark Levinson 20.5 pure class A mono blocks new in 1990. I loved them for their sound and still do. They have been 100% reliable and I have never had them back to the Levinson or my dealer for anything.

However, they are 16 years old now and except for my Magnum Dynalab tuner, they are the only thing I have not replaced in my system.

Being pure class A amps they run pretty hot.

Question is, is it time I should consider having them checked out, refurbished, capacitors and the like replaced, etc?

If so, who should I consider for this work? Levinson? They are not what they used to be when they designed and made these amps, and I'm not sure they are up to the same quality work they did back then or whether I should trust that their parts will be as good as the original. Someone else? But who?

Has anyone been through this or does anyone have any thoughts about this they can share with me?
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zaikesman
3,017 posts
 
Herman: At the moment it's a '64 Fender Super Reverb and a '62 Ampeg Reverberocket that need attention. The Fender did have some parts replaced around 15 years ago, the Ampeg is probably still original. The Fender obviously wants filter caps, the Ampeg surely needs more -- not only doesn't it sound well, but the last time I used it the panel got way too hot. It's actually somewhat remarkable to me how good the Fender continued to sound almost right up until it crashed, even garnering copious praise from other players who were pressed into using it onstage. But then a pre-CBS blackface Super is an all-time great amp.
herman
1,974 posts
 
The last time I rebuilt a Super Reverb the guy kissed me after he played it. At least it wasn't on the lips. (I'll probably have one of those giant beer cans fall on me now) Find somebody who knows what they are doing and you will be happy with the results.
unsound
6,115 posts
 
Herman, I don't have any strong conviction on an absolute length of a caps reasonable use. I am led to believe that caps can be reasonably expected to be reasonably servicable for 20 years. What do you believe the life expectancy of a cap to be? When is a caps qualitive use expired? How often should amps like the Levinsons require maintance? I suspect that the quality and value of the caps used in circa 1990 Mark Levinson products were appropriate for its intended use. Now, if HK believes that their products need service every 10 years, who am I to argue. Then again, I might be a little less cynical if that suggestion came from the original designers/manufacturers rather than a new holding company.
herman
1,974 posts
 
What do you believe the life expectancy of a cap to be?

That's the $64,000 question. I don't have a strong conviction either because it is impossible to put a number on it for any given capacitor. Naim recommends 10 years. Cynics say that is just to generate revenue, Naim devotees say it is essential for maximum performance.

I would agree that in many applications they can be "reasonably serviceable" for 20 years, but most audiophiles are not going to settle for anything reasonable.

If I intended to keep my $35,000 amps and they had 16 year old electrolytics I would have them replaced
unsound
6,115 posts
 
"Most audiophiles are not going to settle for anything reasonable". LOL! Makes one question how "reasonable" audiophiles are?
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