I have a Vibrato/Distort, Reverb/Boost pedal with RCA plugs on a 6' cord for sale. Works fine, some minor paint chipping and very light surface rust on the back.
I know it works for the Vibrato/Reverb on the old tube 100 and 1000 series amps, and I'm pretty sure it works on the Concert/Coliseum? series amps for Distortion and Boost.
$45 shipped CONUS