YES, that's about it. White smoke and all. Harold/Bob
That 813 amp. I was maybe 16 years old. It had a set of mercury vapor
rectifiers in it... Well I always heard you didn't want the mercury to RUN
into the plate and cathode, so I jumpered a 5 volt supply to keep the
filaments lit to keep the mercury liquid, (instead of removing hot tubes).
When rolling it upside down.
Quick repair with the motor running, like a NASCAR pitstop.
WELLLL.
The 5 volts backfed the filament xfmr... Which backfed the plate
transformer, which made about 2000 volts of DC...
You should have seen the look on my face when the finger made contact and
the High School class ring made contact to the chassis.
My hand bounced around in the 100# chassis for a second or two and I finally
got it out.
Stupidest thing I ever did.
Cost to build that amp? Under $20 bucks all surplus junk. It put out a KW.
AWWWW he's got to learn all these things. However, those Svetlana things
he wants to screw in... MAN they're about the easiest tubes to kill on the
planet. Talk about lighting cigars with hundred dollar bills.
Learn with a throw away bottle first. That guy with the three 813's... Buy
them. They are like fuses. Throw the amp away when you are done. The low
plate voltage will keep you from dead when you land on it.
572B's are good learners too. But nothing beats an 813!
Seriously, I think I still have the original EIMAC/QST construction
bulletins from the 60's/70's I think one of the set was a pair of 4-400's
and one a set of 4-250's... A 4-1000 amp and I think the original 4CX1000K
tube one is in their too...
I had written Eimac and they sent me the stuff out when my uncle from
Collins Radio handed me a stack of 4CX600J pulls during one of his visits.
My first amp (after building my first couple novice transmitters) was the
QST 3 807 amp. One tube was a clamp. I learned the importance of grounding
chassis together I was touching a switch on each chassis and there was 800
volts between them. That's when I learned I liked voltage.
NAW I played Bass in a Grand Funk - Zepp cover band called
Zarinski-Cornelius. But thanks for remembering me. :-)
BOB DD
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