10kl & 50kl trim pots

[blues man]

Does anybody know what the watt rating is on the 10 & 50kl trim pots Doug sells? I would assume they are probably 1/2 watt.

[HotBluePlates]

Most likely, they are about 1/3w or less.

It shouldn't matter much, because there is very little current through the pots. It would matter if the trimmer was used to divide couple-hundred volts, but dissipation is probably under 1/6w in a typical bias circuit dividing up 40-50vdc.

[blues man]

Thanks for the reply. I was thinking of experimenting with the 10kl on the preamp with the cathode bypass cap for tweeking.

[HotBluePlates]

They should work fine for that, as far as power rating goes.

One formula for power is Voltage²/Resistance. A typical Fender gain stage will only have 1.5-2.2vdc across the cathode resistor.

2.2v²/470Ω = 1/10th watt. Even less for higher resistances.

You don't want to dial the cathode resistor to 0v, so put a 470-820Ω resistor in series with the pot to set a minimum resistance.