Levinson 20.5 monos - Time for a Refurb?

Herman: Hey, I need to get two vintage tubed guitar amps serviced for new filter caps (at minimum) right now. But I will say that most of the original caps in each of these lasted about twice Unsound's 20 years.

Porziob: The useless comments from you just keep on coming, don't they? Nsgarch wasn't responding to the threadhead in the post you criticized, he was addressing Joemt's concern from 8/2. It's a little thing called trying to help somebody, and pseudoscience wasn't involved. If you can only get your thrills from predictable negativity and weak sarcasm, the least you could do is take the trouble to read what you're attacking first.

To re-confirm the obvious, do replace those caps and also check other vulnerable components as suggested above.

I also VERY strongly recommend you find/purchase/otherwise obtain the SERVICE manual for your amps. Had you had that now, you could have changed caps (usually no big deal) yourself as well as checked all the tests points to see if anything else needs looking into.

Lastly, low voltage caps & resistors cost very little. Of course, the "safety factor" of having Harman service yr amps is very important; however, given a service manual, a competent & experienced electrician -- or experienced & knowledgeable diy friend could do the actual job just as well.

Get the Nuforce 9, listen to them about 20 seconds and you will decide the $2,280 to get ML20.5s up to shape is a real bargain!
I would check caps and resistors myself, not really brain surgery...

Nsgarch,

I've tried a couple of things. First, I checked the
batteries in my crossovers ( Vandersteen #5 ), they were
good till 2009. Next disconnected the subs and ran
direct. Still had the noise. I've now plugged the amp
into a Line conditioner and things seem better so far,
I'll continue to listen. Still have a slight buzz, but
that's with my ear up to the tweeter. The crackle seems
to have died down. The other speaker is dead quiet. If
it is electrical noise, why only one channel? I'm on the
East Coast, everyone running AC's. My one power
conditioner reads just under 100 volts. The other
conditioner ( for the front end components ) gets power
from an Exact Power unit first, it ALWAYS reads 121 volts.
I can't reach the Exact Power unit with amp chord.

Hope things cool off by the weekend, perhaps it's all
due to dirty electric and low voltage. I will clean and
check all the connections as well, can't hurt.

Joe T.

Zaikesman, you say the caps "lasted about twice Unsound's 20 years."

What that really means is they lasted that long without a catastrophic failure, either shorting out or losing so much capacitance that your amp started to hum. The amp works but it is impossible for it to be working as well as it did when it was new. The situation in tubes amps is also worse because the caps have much higher voltage sitting across them than a solid state amp, and the amount of capacitance even when new is much lower than a solid state amp.

I used to hear all of the time that a player didn't want to replace his caps because the amp would no longer be original. That is equivalent to saying that you don't want to replace the original tires on a vintage car. Things wear out and need to be replaced. If you don't do it the object (amp, car, etc) will eventually become worthless for its intended function.

What amps do you have?