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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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herman
2,256 posts
 
"if it's not broke don't fix" will only take you so far. What about preventative maintenance.? Your car runs fine but you change the oil every so often.

Electrolytic capacitors lose capacitance, start to leak DC, and have an increase in ESR as they get older. At some point they will begin to fail. The big question is when.

There is no definitive answer to your question but after 16 years it is reasonable to consider replacing them. Pretty much any competent tech can do the job. The hard part might be finding caps that are the same capacitance, rated voltage, and physically close to the same size.
aball
2,016 posts
 
I totally agree with Herman. It was very funny to see so many "if it ain't brokes" when other guys on this site will replace perfectly new caps to get a "tweak" improvement and not even think twice about it! Hilarious.

From an electrical engineering standpoint, those caps most definately need to be replaced - there is no question. Those amps run super hot and after 16 years, I bet there are even cracked resistors in there. The amps will definately benefit from an overhaul: Power will return and with it will come improved acceleration, er, I mean, dynamics, and bring along everything else that entails.

I am glad to see you following your gut instinct. Go ahead and send it back to ML and be sure to let us know if your sound improves. Get a quote though because it may take a very healthy dose of sentiment to pay the bill. :) Arthur
dpac996's avatar
dpac996
701 posts
 
will cost at most $950 via Harmon Intl.
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cipherjuris OP
145 posts
 
Here's my update. I talked with ML via Harmon. As expected the phone tech (Jaime) said that if they are 16 years old and have never been serviced, they should definitely come in for inspection and maintenance. He said they recommend that you send them in about every 10 years.

There is a Guaranteed Maximum Price of $1,140 per amp or $2,280 for the pair. If the actual work is less, then they will charge less but if it is more you will still pay only $2,280.

All he needed to issue me an RMA# in addition to my name, address, etc. was the SN of the amps.

Best,

Ed
joemt
22 posts
 


I have a ML#27.5 which has gotten alot of use and also
is left on 24/7. I just started noticing a slight buzz
from the left channel tweeter along with occasional
static/crackle. Kinda like AM radio during a thunder
storm. Obviously not that loud, I need to get close
to the speaker to hear it. It can be heard from my
listening postion during very quiet times. Is this the
sign of a cap going bad?

After shutting down the pre-amp, the noise continues.
I guess that eliminates upstream components. I'm hoping
not to go through yet another repair cycle.
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