A musician wants to play his amplifier at rather high volume to get the sound of distortion as he likes it, but not annoy the neighbors. In math, that resembles changing 106db to less than 70db for a minimum range of 36db SPL. Retail power attenuators are designed to smoothly attenuate from maximum power to some lower level. This approach requires a high wattage rheostat. I designed to avoid the High Watt rheostat. This means the minimum attenuation is not a tiny part of a db. It is 18db (measured) to use a 5 watt potentiometer and 25db (measured) for a 1.5 watt audio taper pot. The largest wattage of audio taper pot that I could find is 1.5 watts, so the 5K 5W solution is a linear taper pot. The resistor to help a 5 watt pot survive is 80 ohms (82 ohms = standard size) 18W and the resistor required to help a 1.5 watt pot is 267 ohms (270 actual) 6 watts. My design contains a bypass switch to avoid changing the wiring every time you want to not have the attenuator in the circuit.

I know the math says -20db and -31db. The measured response does not match the math. Sorry, that's the tools I have to work with.

I know the math says -20db and -31db. The measured response does not match the math. Sorry, that's the tools I have to work with.

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