o.c. elect. cascade reverb tank.

Accutronics and other related brands publish specs for their pans. Inputs are rated in IMPEDANCE, but they also list the DC resistance of the transducers.

Measure the DC resistance of the drive end, the end marked INPUT. It might be 1 or 2 ohms or maybe 200 ohms. Whatever it is, look up the closest equivalent on the accutronics chart. Then we will know what sort of drive the thing expects. Low impedance is generally driven by a transformer, which higher impedances in old amps were driven through a cap from a plate, or in more modern times via op amp ICs.

There is nothing special about them, they were just a competing brand to Accutronics. They work the same, and will have similar impedance choices.

remember, this is guitar amps, not rocket surgery, so close is good enough.