[Amps] step start

[Victor Rosenthal 4X6GP]

Why do you want a soft start on either plate or screen voltage? What 
function does it serve?

73,
Victor, 4X6GP
Rehovot, Israel
formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/

On 02/10/2023 15:14, Paul Decker wrote:
> I was thinking the step start could be put onto both the screen and the plate voltage transformer. Since the screen dumps into a 1 Henry, it does take some time for that to charge so they both should ramp up.
> 
> It's easy enough to have the soft start only on plate and when the soft start kicks out, turn on the screen voltage.
> 
> Paul
> 
> 
>> On 10/01/2023 3:43 PM EDT MU 4CX250B <4cx250b at miamioh.edu> wrote:
>>
>>   
>> Nice project, Paul. I built my first tetrode amp a couple of years
>> ago, and I was dubious I could carry it off, but it worked well and
>> was fun. I have website at w8zr.net with photos and schematics.
>>
>>   Re your questions, a 300V drop in plate voltage won’t be a problem.
>> That’s a pretty typical  voltage drop and isn’t anything to worry
>> about. Re your soft start question:  for a tetrode amp, you should
>> always have the plate voltage turned on BEFORE  turning on the screen
>> voltage. In other words the screen voltage should never be on by
>> itself. Doing so will quickly destroy your 4cx1500b. To be on the safe
>> side, I would turn on the plate voltage and the cut-off bias voltage
>> when the amplifier is powered up and just leave them on. Once the
>> plate voltage is on, you can then safely turn on the screen voltage.
>> On my homebrew tetrode amp, I made a little interlock circuit that
>> monitored the plate voltage and shut off the screen voltage if the
>> plate voltage dropped out for any reason.
>> 73,
>> Jim w8zr
>> Sent from my iPad
>>
> 
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps