One could simple look them up in a tube manual, but in 1974 I used a amplifier
using 4 1625 tubes in grounded grid, driven by my SB-102 . After they croaked I
hooked a 813 tube us using wire wrapped around the pins and shoved into the
tube socket. The 813 and the 4 tubes each had simular power lever, somewhere
around 500 input. I have that memory of 30 years ago, or so. If it doesn't
play tricks on me. I must have sold it , probably for nothing
.........compared with today
john kb9tc
StephenTetorka@cs.com wrote:
Hi Guys:
Appreciate your generous help on my previous matters.
Permit me kindly to ask for help on this one.
I have a 1948 homebrew using 2 each 1625's in RF deck.
Its modulated by 2 each 807's.
It works.
But - I'm not sure that I have the grid bias at the 'proper value'...and the
output is lower than I'd expect for these tubes..unless they're weak...which
could be since I've been hard on the rig in my attempt to get it operating.
Presently, the grid bias is at -56 volts.
The 'Book' says -90 for telephony @ 600 volts on the plate ( I've got 700 ).
The gent who built the rig - W2PLY - apparently used -35 volts or a C
battery.
The two 1625's are in push-pull and link coupled to the output coax.
Sooo..the big question is...how do I know if I've got them at max ouptut?
Tnx,
Steve
WA2TAK
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