The Fine Things are Always Hand Made
I acquired a 15" field coil speaker for my Philharmonic project.
Absolutely similar to this:
Its shape is perfect but I confused by field coil DC resistance ( about 5KOhm).
Can you somebody share the information about the field coil resistance of the original speaker ?
I know its field coil has a middle point.
I'll may be able to disassemble my speaker and rewind the coil for achieving necessary parameters.
The field coil spec for the 15 inch pedestal speaker for the Philharmonic AM/SW model is 925 ohms resistance end to end. It is tapped at 525 ohms measured from the B+ source coming from the 30 henry choke. The amp needs close to that field coil resistance to produce the 125 volt drop required for the power/amp to provide the required voltage to the radio.
The correct 15 inch Scott speaker has a 38 ohm voice coil and the output transformer located inside the pedestal base. However, I do not see an output transformer on the speaker in your photo. You will need an output transformer rated for 6L6's in push-pull. Also, it is unlikely the 1950 Magnavox speaker has a 38 ohm voice coil. You would need to determine the resistance of your actual voice coil as part of determining a workable output transformer.
David, thank you very much!
Your information is very useful.
I have the speaker set ( speaker, pedestal base with transformer inside) from AW23.
Unfortunately its 12" speaker has no cone.
I'll install 15" speaker and adapt the output transformer to new 15" 6 ohm speaker.
Still have no any amp\power supply. Would be happy to buy an original Phil's amp.
The AW-23 speaker has a couple issues.
First, the AW-23 used 2A3's in push-pull parallel. So the output transformer is not appropriate for the 6L6's of the Philharmonic.
Second, Scott changed the Voice coil mid production, from 38 ohms to 19 ohms. So there are 2 versions of the AW-23 speaker, (and 2 versions of the optional tweeter set)
Finally I got the original Philharmonic power supply/amp chassis. I'm going only to take a pedestal from my AW23 speaker.
What's left to know is the parameters of the Phil's output trans : iron size, resistance, inductance, wire diameter, etc.
Are its dimensions similar to AW23's transformer ?
If you have the speaker set disassembled - can you make measurements ?
I do not have the data you seek, other than the resistance previously offered.