For sale is a Boss RX-100 spring reverb unit from the 1980s. This unit has a mono 1/4" input (Channel A) with switchable sensitivity from mic-level to line-level, as well as a stereo line-level RCA input (Channel B). Output is 1/4" mono or RCA stereo. There is only one spring tank, so this is not truly a stereo effect; the MODE switch simply enables or disables a simple phase-shifting circuit on one of the RCA outputs that gives a vague impression of stereo reverb.

I have modified this unit for better performance and so that it is more useful for studio work, as follows:

-       Modified REMOTE SW jack to instead be TANK OUT, taking signal from junction of C23 and R34. Grounded the wire previously connected to jack tip.

-       Modified PULL REVERB ON switch to PULL DRY ON, allowing dry signal from Channel A to be present in or absent from the output. Channel B is now always connected to the tank input, and always appears in the output.

-       Added 470µF from pin 3 on IC3 (which is an AC ground) to nearby ground trace, greatly reducing leakage of distorted dry signal into wet output.

-       Glued loose transducer coils.

Thanks for looking, and feel free to ask questions or make an offer!