[Amps] One PS, many amps

[Ian White G/GM3SEK]

Phil Clements wrote:
>
>> >I believe I've read on here before where some owners have built MONO band
>> amps but powered them all from a single power supply.  So, one power
>> supply deck and TWO RF decks.  It has been suggested that I use vacuum
>> relays to switch between the two RF decks.  I was hoping to have them both
>> run in standby at the same time.  I obviously do not know enough and am
>> therefore here seeking guidance.  I will only operate one amp at a time.
>
>Frank Donovan, W3LPL is probably the world's best source of info on 
>this type of lash-up. His multi-multi contest station, as I recall, had 
>amps for each band, with only one power supply. It may still be in 
>operation.
>
>No, you don't need any relays to switch HV; just excite the amp you 
>want to use. I would highly recommend HV glitch resistors in each RF 
>deck, and also in the power supply.
>
A separate resistor in each amp would reduce interaction and voltage 
drop, but a resistor is needed in the power supply as well, to handle 
the situation where one of the B+ leads shorts to ground.

Each amp also needs its own separate anode and grid current metering. A 
Triode Boards customer is looking at this right now, and I think I've 
second-guessed how Frank must have done it, with isolating diodes in the 
B-minus return.


-- 
73 from Ian G/GM3SEK
http://www.ifwtech.co.uk/g3sek