Update: The last two batches of VacTec Vactrol Optos we bought were counterfeit - so it’s very likely the bulk of the OEM parts are either gone or fake. So for now we’re switching to only Xvive, which we get directly from Xvive and are authentic work-alike replacements.

These opto couplers are used in the Janus preamp tremolo section. They are matched to the original response curve of the Vactec optos used by Rhodes. Blind tests reveal soldering in replacements is much easier with your eyes open.