in article , truegridtz at
wrote on 6/12/05 2:29 AM:


"Jon Yaeger" wrote in message
...
A really nice tube amp!


http://cgi.ebay.com/ws/eBayISAPI.dll...PageName= ADM
E:B:LC:US:1


TIA,

Jon, So how do you know the filters don't leak or have excessive ESR? A
variac keeps it from going up in smoke, but it doesn't repair bad caps.

*** I check the caps with a capacitor tester. I reformed the electrolytics
over a long time interval. They run cool.

How do you know that all of the paper caps don't leak? Aren't those the
black beauties/bumblebees that are notorious for leakage?

*** Yes, they are black beauties and Sprague caps. I checked the voltages
across the caps and looked for leakage. I also touched them to check for
heat. In my experience, leaky caps often get hot.

*** I haven't had much bad experience with the bumblebees. If I suspect a
bad cap, I'll take it out of circuit, put a 1K resistor in series with it,
and connect it to a HV power supply and measure the voltage across the 1K
resistor to determine leakage. I did not do this with this amp, because I
didn't think it was necessary.

I have never seen one of those old black plastic caps that didn't leak
current and/or oil. I had hundreds of new ones and threw them all away,
leaky garbage. But, that
was before I knew that suckers would pay $30 each for them on ebay.

*** I do have a bag of bumblebees and I I'll test your theory and report
the results here.

"This amp will bring a lot enjoyment to the buyer with a minimum of fuss."

If those are the original caps, I wouldn't bet on it. Mark

*** Yes, caps do fail in McIntoshes from time to time. However, I think
even you would be surprised at the number of similar amps out there that
have most if not all of their original capacitor compliment. Are they just
hobbling along with their leakage and other infirmities? I don't know . . .
.. my sample isn't large enough. But they are still playing music . . . .

Jon