[gfehlman]

What is an available audio output transformer that will work in place of the existing original transformer Philco 32-7754?

[morzh]

You need 10 kOhm load.

If you know your voice coil impedance (or at least resistance) and the power reuqired, pick from 125 Hammond series.

https://www.hammfg.com/125.htm

Let's say you have 4 ohm. (I do not know what it is).
You need 2500 times that, which would make it 50 turns ratio.
The closest one then would be output leads 2 and 4.

https://www.hammfg.com/electronics/trans.../125a-125e

125B would give you 5 Watts, 125C - 8W.

In any case, you will be able to match most speakers to most tubes in pushpul using 125.