Hi folks, thanks for reading.
I am building an amp with four 3-500Z using low bands only (160 and 80m).
I do have two filament transformers, 5V/80A w/o a center tap on the
secondary coil. The other one contains four coils with 5V/25A ea. coil also
w/o any center taps on the secondary side.
My first *wrong* idea was to connect all four coils in series and all
tubes should be feed in series, between the two middle coils I would have a
center tap connecting (via bias circuit and ammeter) to ground. But this
is wrong of course! The cathode current of one tube will run over the
filament to the over one etc.
Does anyone know an other idea to use one of the filament transformers for
my low band amp?
For the final pi net I will use silver plated wire 3.0mm diameter wound on a
commercial coil body (was using for a 500 kc 3K amp). I guess 1.5 amp plate
current and a Q=10 to 12 the "swing current" in the pi-net coil will be
approx. 15 to 18 amps. The wire should be thick enough for this current?
Does anyone of the experts agree with me?
Cheers, Werner DJ2HZ
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|