Volume - remote control?

[Doctorandus_P]

Back in the '70ies volume control was sometimes done with LED's and LDR's

[FriedMule]

My reason for the opto is to galvanic isolate the audio signal from the controlling power, to let the audio run through without having to clean up the power and be able to select the best chip for dimming the opto, not caring if it "sounds good".
Also, it could be a "funny" detail to play with, to only have a single FET, acting as the clamp on the signal. But is there anything stopping me in using the potentiometer-chip to dim the opto instead of "dimming" the audio signal? :-)

[ssashton]

If you want galvanic isolation, why not use multi-tapped audio transformers with relays to select the level?

Distortion performance of well made transformers can be excellent. Look at Stevens and Billington TX102 as a good example. https://www.diyaudio.com/forums/analog-line-level/258175-stevens-billington-tx102-passive-preamp-built.html

I had some and tested 2v RMS distortion below -120dB IIRC.

LDR (light dependant resistor) are a niece choice for volume contoll. Check out the 'Lightspeed preamp'. https://tortugaaudio.com/top-5-reasons-to-choose-ldr-passive-preamps/