[Micro9]

Will a speaker from an philco 89 work in  model 20?

[morzh]

Well.....the Field coil in 20 is 3100 Ohm and in 89 is 1100 Ohm.
You will need to add a resistor in series if putting the 89 speaker in 20.

And this does not account for the transformer. It has to be replaced by a P-P as it is a SE.


Also, the 89 speaker is 1.2 Ohm VC and I do not remember exactly but I think the 20 is 0.7 Ohms VC so the Philco transformer will not match the impedance properly even if it will work not optimally, so you might need a new transformer, like a Hammond with adjustable In/Out ratio.