Heater supply question

[John]

What would be the effect of putting a 4700uf/6.3 volt capacitor in the heater supply? I've not seen this done, and know there must be a reason. I was thinking it would help with hum, (if hum is a problem) or does smoothing out ac ripple really not work the way I think it does?

Also, is it okay to insert a diode in the heater supply to drop the voltage a little?

[sluckey]

What would be the effect of putting a 4700uf/6.3 volt capacitor in the heater supply? I've not seen this done, and know there must be a reason. I was thinking it would help with hum, (if hum is a problem) or does smoothing out ac ripple really not work the way I think it does?

It would be kinda like putting a 1/2 ohm resistor across the filament winding. You'll draw about 11 amps. Probably not good for the cap or your PT. It won't do anything for hum.

Also, is it okay to insert a diode in the heater supply to drop the voltage a little?

Only using one diode will drop the voltage a lot. Using back to back parallel (reverse polarity) diodes is a way to reduce filament voltage approximately .7V.

[John]

Probably not good for the cap or your PT.

No, probably not!

Only using one diode will drop the voltage a lot. Using back to back parallel (reverse polarity) diodes is a way to reduce filament voltage approximately .7V.

Thanks!