I have recently started rebuilding my first Philco, it's a model 39-116.
I have replaced all the wiring, capacitors,but need a speaker. Anyone have one that works ? Can I replace it with a common 8 ohm speaker? I have the schematic but it doesnt tell me how many ohms or what the resistance is on the transformer that used to be mounted on the top of it.
Hi "mister"
I think your speaker is a 12 inch unit? It is electrodynamic, with no audio output transformer mounted on it. It has an 860 ohm field coil, and either a 3 or 5 ohm voice coil - a quick look through my stuff does not reveal the exact specs on this speaker's voice coil, maybe Chuck has this info?
It could be replaced with a modern PM speaker, but (1) you would have to add a 850 ohm, around 25 watt, resistor under the chassis; and (2) original-type speakers are not that hard to find; in fact they seem to show up on our favorite online auction site (eBay) quite frequently.
Good luck,
1939 Part Catalogue:
Speaker 36-1450
Type "H" 12" electro-dynamic
Voice coil impedance @400 cycles = 5.1 ohms
(this is NOT the D.C. resistance measured with a meter.)
Field coil 860 D.C. ohms
Thanks for the assist. I have the earlier part catalogs through 1938, then 1941, 1946 and a couple of later ones - the 1941 and 46 catalogs show that speaker as still being available for purchase at that time, but do not give its specifications.
Thanks for the fast reply guys. I'll be checking Ebay.