As some of you already know, I've recently switched from using inductive volume controls to using low impedance (500-600ohms) pots or stepped attenuators. However, I didn't have anything that would fit the bill that was stereo, and the 500ohm Daven stepped attenuators I've been using lately are linear rather than audio taper, which even with the very low gain of my screen drive amps have too large a change in volume for the lower steps. With loud source material, volume goes from off to too loud for background music at dinner time in the first step. Turns out I had a stereo 23 position switch that I'd never used for another project, so off to the races. This attenuator is not linear taper, but not a standard audio taper either. Resistance values are as follows:
72, 37.5, 37.5, 37.5, 37.5, 37.5, 37.5, 37.5, 37.5, 37.5, 37.5, 37.5, 37.5, 8.45, 8.45, 8.45, 8.45, 8.45, 6.81, 6.81, 6.81, 6.81 for a total of 591.49ohms. Resistance values determined by what I had on hand, not calculated for audio taper... Sometimes the best parts for the job are the ones in the parts bin
Haven't put it in anything yet, but it ought to give a lot more fine control at low volume settings. Here's what the completed unit looks like:
Roscoe
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