Hello All,
I'm building an LCLC supply for a preamp, and wondering about the necessity of a bleeder resistor. The circuit has gas regulators drawing 45mA total in shunt from the HT to drop the voltage down to 225V, so once they strike, there is no need for a bleeder, as the minimum current for the 17H input choke is easily satisified. The voltage will climb higher before they strike, but all the circuit components are rated for far more voltage than the circuit can obtain in cap input.
The glow tubes act as their own indicators if there is a problem - no glow, then I know to shut down. Safe, right?
I'd rather not waste all that power and generate unnecessary heat if it's not necessary.
I'm building an LCLC supply for a preamp, and wondering about the necessity of a bleeder resistor. The circuit has gas regulators drawing 45mA total in shunt from the HT to drop the voltage down to 225V, so once they strike, there is no need for a bleeder, as the minimum current for the 17H input choke is easily satisified. The voltage will climb higher before they strike, but all the circuit components are rated for far more voltage than the circuit can obtain in cap input.
The glow tubes act as their own indicators if there is a problem - no glow, then I know to shut down. Safe, right?
I'd rather not waste all that power and generate unnecessary heat if it's not necessary.
Hi!
The bleeder provides some safety. If the gas tubes don't ignite for any reason or tubes are not plugged in, the bleeder will ensure that the caps are discharged when you turn off. Some caps can hold their charge for days!
If sub critical current is drawn from the PSU, the output voltage will be up to 50% higher. Ensure your caps have a high enough voltage rating for that so nothing gets damaged just in case.
If you do not want to place bleeders which draw the critical current, at least install some with a higher resistance which will dissipate less power, but still ensure discharge of the caps in any case.
Best regards
Thomas
The bleeder provides some safety. If the gas tubes don't ignite for any reason or tubes are not plugged in, the bleeder will ensure that the caps are discharged when you turn off. Some caps can hold their charge for days!
If sub critical current is drawn from the PSU, the output voltage will be up to 50% higher. Ensure your caps have a high enough voltage rating for that so nothing gets damaged just in case.
If you do not want to place bleeders which draw the critical current, at least install some with a higher resistance which will dissipate less power, but still ensure discharge of the caps in any case.
Best regards
Thomas
Yes, I've already breadboarded and listened to the preamp portion of the circuit using a different, CLCLC power supply, and using a 0.1uF Multicap PPMFX to shunt noise to ground around the VR tubes. VR tubes are fed from a cascode CCS. Worked like a charm with no oscillation detectable on my scope.
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