Is this power transformer up to the task?

[makinrose]

Greetings

Perusing he Hammond replacement transformers for guitar amps, specifically the Super Reverb and the Bassman, I find that the 290D2X is listed as a suitable PT for both. This is rated at 300mA for the plate winding, just as you mention above. Might this be the device in question?

You also mention an OT of 6k6 in the first post, but a correction of 4k as the Bassman OT. Even though the Bassman OT would be "wrong" in a Super or bandmaster, it seems compatible with at least the Hammond PT clone.

Cheerio

A 6K6 is the power tube type in the tube reverb circuit.  Fender used 4K for the Super, Vibroverb and Bassman---anything Black or Silverface during the 60's and 70's with a 40W output rating.   The Bandmaster and Pro used a smaller OT unit, but it was also usually 4K during those years.

The transformers in question are all Mercury Magnetics designed for the Vibroverb.