• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Preventing arcing on standby switch?

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I thought about adding a parallel Ressistor and Capacitor over a standby switch to prevent arcing and burning of contacts.

I have good film cap: 22000pF (0.022uF) 1500V (good old Ei Niš) (I have couple of them)
in series with 1k 1W ressistor
Should ressistor be greater or not?
Thanks in advance :)

Edit:
There is 190V-0V-190V before silicone reactifing, so about 265V is at switch.
 
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Are you using the switch to connect the CT to ground?

If so, then the switch would see an AC current. If you are using solid state diodes then you probably have a high level of filter capacitance directly fed by the rectifier, and so the turn-on current pulses will be relatively high, and if that aligns with switch contact bounce then arcing from transformer leakage inductance would be quite significant.

An RC snubber would allow a current path to continue when the switch bounces open, rather than forcing an arc at the contacts. A resistance of 10-100 would be fine. The most benefit is when the RC is physically small and close to the switch.

Another technique is to reduce the magnitude of the charging current at turn-on - such as by using a NTC resistor sized for the job.

Another technique is to add a bypass resistance across the switch to allow a bleed charging current to raise the HT to say 50-100V. This would reduce the initial charging current level, and also run the tubes with some anode voltage rather than just heater only.

Ciao, Tim
 
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