The Fine Things are Always Hand Made

Philly speaker substitute

I am in the process of restoring an early pointer dial Philly, only problem is I don't have the Magnavox speaker or tweeters that belong to this radio,

here is my solution to the problem, not original but it works ok, and if the correct speaker can be found it's just a simple matter of swapping over,

the field coil is replaced with resistors, there is around 17 watts of heat to dissipate hence the large heat sink and die cast box,

my late type psu uses a 10 way Jones plug, this can be seen in the photo.

The cable is sleeved in woven cotton tube, dyed a sand color with rit dye to match the older existing radio leads, the ends are fixed with glue lined shrink tube.

Here is a shot under the chassis,

the four output terminals on the right hand side of the box, allow for a modern 8 ohm speakers to be connected,

I fitted a 2.2uf cap mounted behind the tag strip at the top of the photo, this is in the original Scott schematic as a crossover for the tweeters.

Three 50W metal clad resistors are used to help to spread the heat dissipation, the values chosen give a very close approximation to the original field coil.

I have also added a 20uf motor run cap from the center tap of the output transformer to chassis, not originally fitted, but as the inductance of the field coil is missing, a bit of extra decoupling wouldn't be out of place here,

here is the Jones plug version schematic,