4.6 preamp potentiometer replacement

It’s an oldie but goodie. The potentiometer on a 4.6 is starting to malfunction. It will skip to full volume at time when turning either up or down. I’ve been working around this by using it in straightwire mode until it settles and then am able to switch it into high pass. I’ve removed the potentiometer and there isn’t a lot to go by as a replacement. It a 50k ohm, 2x and it may be a siemens make but it doesn’t have mfg markings on it except for an “s” in a square. Model 7730. The entire line of text on the pot is 150Y50KΩX2 7730, having a hard time locating a replacement pot for this old component. 6 pin, 6mm cicle shaft, 20mm long.

I’d contact PS Audio to see if they have any advice. If you can find the same/similar physical package and pin locations any 50K audio taper stacked (two ganged potentiometers) should function just fine. If you want to get a bit “wild” you could try to shoehorn one of these magnificent DACT stepped attenuators in there. They are about $250 though. Just replaced my noisy pot in a Bottlehead Stereomour II tube integrated and love the results.

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Might have some luck at Mouser

Electronic Components Distributor - Mouser Electronics


You could look into one of these from Tortuga Audio;

Thank you very much for the replies. I did search Mouser and Parts Express. There is an ALPS that is very similar, 27mm shaft which is 7mm longer than current, The major downside are the pin locations are tighter fit, 5mm distance, current is 8mm. I ended up carefully taking apart the pot and cleaning it all up, it had a lot of coal black deposits on it, one of the tines on one of the wipers was slightly bent, I aligned that rouge one with the others. Carefully reassembled and resoldered it into the board. Issue is solved. I’m not much of an electronics guy but was super satisfied that it was a successful fix; and the whole thing didn’t spring apart or turn to dust. That is usually my luck.


Well done!