>
>Recently picked up a well used Clipperton. Has 4 new 811A's that I plan on
>using with the lower plate voltage.
With a rated diss. of only 65w, 811s do better when tuned with a tuning
pulser. However, if you have a free supply of new tubes, you needn't
bother.
>Have some questions that hopefully can
>be answered here.
>1. I assume the 9.1 Zener is used for idling plate current via the relay on
>TX.
correct
>2. Also assume the 47k resistor via the relay is for cutoff bias on RX also
>via the relay.
yes - but a g-g amp will work fine business without one.
>3. I used a 47ohm/220pf combination on each grid to ground as did Collins in
>the 30L1. That should get 4.7 volts bias on each grid with the thought that
>with about 1700 volts on the plates some bias would be needed.
>4. Why no filament center tap. If I need to, can I use a 22 ohm resistor
>from each side of the secondary to make one ??
not enough conductivity. A pair of 2.5-ohmers in series make a better
semi-CT.
>5. What is the recommended safety for spikes? I used 10 ohms in the B+ line,
>are back to back diodes still the cure on the B- ??
For limiting the drop across the grid-current meter shunt R, 3A diodes
work fairly well. 1a diodes are prone to fail.
>6. Tuned input, can anyone send me the values needed for 10-160 especially
>160 as the HB has 10-80 that I guess would be OK.
>7. Can a parallel tuned circuit be used on the input rather than a pi. or is
>the bandwidth too narrow without a pi?
>
pi networks with a Q of 2 is what works best.
cheers, Ed.
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|