The PHILCO Phorum

ok I am working on a philco 490 dose any one have a photo of a k-3,k-4 or a k-25 speaker
Benny

Hi Benny,

Sometimes called a pie pan speaker they were used on the models 20,21, 70, and 90. The speaker seems to be all the same in terms of specs but the output transformers are different, some are for p/p output and others for single end output. One from a later version of the 90 or a model 70 should be fine for your application.

thank you Terry for the photos I have a speaker like this. it seams to me that the wires from the speaker to the chassis should be a bit longer
benny

Perhaps your spkr came from a baby grand (table top) set rather than a console. The important issues are the output transformer, does it have 4 or 5 wires ? If it has 5 wires it would be for a push/pull output stage which wouldn't give you a good impedance match for your single 47. You want to see 4 wires.
And the other is is the field coil good? If not then you will need to rewind it or find a spkr w/a good one.
Lead length isn't much of a problem, at 80+yrs old it would hurt to replace them anyway.

single 47, 3 wires what's the best way to rewire the speaker portion of the speaker do you think I am careful I could remove the cone to unsolder the old wires
benny

Typically rewiring the spkr wouldn't require unsoldering the voice coil just replacement of the wires connected to the primary of the opt and field coil. If you need to remove the cone/vc then you would need to unsolder the voice coil. It's soldered to the secondary of the opt and has a little spring contraption that holds the wires in place. It pinches them so you can pry them out gently. Remove the screws along the perimeter of the cone and the one in the center and the cone can be removed.