[Amps] filament instant heating query / simple remedy

[Ron Youvan]

   Rob Atkinson wrote:

> I'm having a hard time believing 3-500 filaments are stressed all that
> much.   I'd be more interested in metering the fil. voltage and being
> able to adjust it.   I know of no commercially manufactured ham amps
> that meter the filament v.   To me that is the amp/transmitter
> equivalent of an oil pressure gauge in a motor vehicle, also something
> you never see in mass market consumer vehicles.

> I would not put the all the AC service through an on/off switch for an
> amp.  I'd use the switch for the AC to a 28 v. relay coil DC supply
> and use relays for the higher current on/off to the h.v. etc.
> primaries.

   Most commercial broadcast transmitters monitor the current through tube filaments and possibly 
the Voltage.  The current is much better because it can't be wrong at the tube like the Voltage can.
   As connections become resistive (bolted connections etc.) maintaining the original current will 
insure a cathode at the right temperature.  The correct current depend on the particular tube or 
tubes.  Set the correct Voltage at the tube filament connection when installed then record the current.
-- 
    73 Ron KA4INM - All E-mail sent to this address shall linger in the Google cloud forever!