Posts: 1,419
Threads: 71
Joined: Oct 2007
City: Linn Creek, MO
I have a NOS Philco output transformer p/n 32-7078 as used on the K-17 and H-13 speakers. Using a variac, I determined the turns ratio to be about 65:1 that gives an impedance ratio of about 4525:1. Pretty low considering the .62 ohm impedance of the K-5 voice coil. I just happened to have an 8 ohm coil the right diameter but, the thing is to long. Also 8 ohms is a little too much.
[Image: https://live.staticflickr.com/65535/4924...6a02_k.jpg] 100_0204 by Steve Davis, on Flickr
So, I removed about one half the turns and shortened the coil form.
[Image: https://live.staticflickr.com/65535/4924...a38d_k.jpg] 100_0206 by Steve Davis, on Flickr
Steve
M R Radios C M Tubes
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RE: Philco 90 Restoration - by Steve Davis - 12-19-2019, 05:47 PM
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