Date: Sun, 11 Apr 2010 09:43:52 EDT
From: Gudguyham@aol.com
Subject: Re: [Amps] HV lytic max V ratings..some notes.
In a message dated 4/11/2010 9:24:56 A.M. Eastern Daylight Time,
Jim.thom@telus.net writes:
I usually sail pretty close to the wind. I work on having 1 spare
capacitor worth of headroom in a bank. For example, if the dc voltage
is 4500V, then I would use 11 x 450VW capacitors in the bank. Never
had a cap go bang on me by using that crude formula.
## It was actually alek from vk land who said the above. I'd use
12-13 caps on any 4500 vdc supply. I look at it in terms of %..
and not.. "leave 450 vdc of headroom"
Denny used 7 caps when everyone else used 8. I just had to recap an
LK-500 because of a bad cap. He always found a way to save a penny. The
worst
blunder I think he made was not only didn't he have a grid trip on the
DTR-2000L, he didn't even have a metering scheme for the grid. Then when he
DID use some sort of grid trip and Hi plate current trip safety measure, it
was on the LK-500ZC with 3-500's. Who needs that?
Yet the DTR-2000L is a highly sought after amplifier, and a nice one will
bring over $1500.00. Go figure. I won't go into not using a filament choke
and using chassis return on the filament supply and a blower that might
handle a 6146.
## The ham dealer in Vancouver BC had one of the 1st ones on display,
back in.. I think 1977-1979 era. We all laughed when we saw this TINY
little fan that..'forced air' through the chimney. This DTR-2000L
did NOT have squirel cage blower of any kind. I used the same size
fan on my... drake T4XC [top lid].. and it had a pair of sweep tubes.
## The guy who bought it.. fried the 8877 after a while. His line V was
a bit on the high side.. and the DTR-2000l already has 5.8 vac on the
fil as is.. and his was even higher still.... = bye-bye tube.
later... Jim VE7RF
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