AO-28 outpur transformer specification

[eenaoo]

Hi,
Do anyone know the AO-28 preamp output transformer specification. Is it 5k:600 Ohms?
I was thinking of replacing my Lesile kit with a kind of custom amp with 0dB gain, with effect loops and the Leslie speed controller. So one idea was to use similar design as in the AO-28 preamp with the 12BH7 tube and the transformer.

Regards Arne

[Jaim]

From my notes - source unknown.

To match the 12BH7 plate resistance you would want about 5K ohm impedance. You need one that can handle 11.5 ma primary current without saturating and handle the max and min frequencies of the audio.

The secondary should probably be 600 ohms center tapped.

Jim

[eenaoo]

Thanks. That was what I thought. Do you know the frequency response, i.e. lower cutoff frequency on the existing 6122 leslie connection transformer?

Arne