It's a heavy load that is driven by a small tube output transformer. I'm not sure that 741 has enough current to drive it.
Depending on the number (stamped on the tank) of the reverb tank, you will have different input and output impedance, and there are several types available...and so it's hard to say what will drive it until you first "decode" the part number, or measure the in / out.
For example 4AB3C1B is 8 ohm in, 2250 ohm out (see charts)
It usually takes quite a bit of drive voltage. This is electrical to mechanical, through the springs, and then mechanical to electrical.