• 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.

wirewound vs standard pots

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I am building a preamp prototyping box for proto'ing guitar amps.

I plan on having two 12xx7 series tubes, 12 values of capacitors for output and cathode for each section and cathode follower switches, as well as selectable values for peaking circuits and a seperate fully tweak-a-stack (heh :D) for tone control.

I plan on having variable cathodes, plate load resistors, and interstage resistors.

Should I use wirewound or standard 1/2 watt pots for the plate load resistors and/or cathodes? I understand that standard 1/2w alpha pots might not be able to withstand very high voltage.

Sugguestions?
 
I don't think wire wound controls will like high voltage any more then carbon pot will. Assuming you mean standard 1 or even 2 what sizes. If HV breakdown is your only concern, you migh try isolating the controls by mounting them on a plastic panel to keep the bodies above ground. And I would use good plastic insulated knobs for safety.
 
actually, I just checked the specs again and their 500v, so I don't think an issue should arise there. I am using plastic knobs, thanks for the reminder. ;)

for regular preamp work, 1/2 watt for resistors is standard, so I would assume the pots shouldn't have a problem here?

Also- queston on how they rate maximum wattage handling on a potentiometer:
Is this maximum wattage at full resistance, theoretically, wouldn't the handling increase a little as you turn down the resistance as there is less area to have to go and more area to dissipate the heat? ( more area being the wiper inside, and less travel being distance between leg and wiper)
 
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