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City: Hay Lakes, Alberta,Canada
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It is 1800 ohm FIELD coil. Your voice coil is likely to be from 0.7 to 4 ohm.
Now that you don't have the speaker and probably missing your output xfmr too, just get a proper size speaker and match the transformer.
The sch is similar to Philco 20 but with A output stage so a speaker from 70 could do.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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City: Roslyn Pa
Or a Philco 90 w/single 47. I think I see one.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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Yep. Thy are practically the same. Or are the same.
PS. Make sure if it is a 90 speaker it is from the one with a single 47 out, not a pushpull one.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Ok! I'll just steal the one closest to the Phonola right now... ;)
Posts: 329
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City: Hay Lakes, Alberta,Canada
So, I did some measuring, and comparisons... and a Philco 70/90 speaker won't physically fit into the cabinet, between the decorative bolts. Actually, none of the multitude of speaker I have around here will fit the bolt pattern they used.
So, I did a bit of research, and using a picture of a similar set I found online, and a same-year battery set I have here...it seems that Grimes was using Utah speakers, made by their Canadian division.
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I have located a speaker that will fit. But, the field coil is 2600 ohms, which puts it 800 ohms higher than the original. I know that one can roughly go 300 ohms higher than the original value, without affecting the B+ voltage too much. But those calculations are also based on a +- 110 volt power source. Out here in rural Alberta, where I live, the line voltage is running 128 volts. Does anyone have experience using a speaker with a higher field coil value? Maybe the B+ will still be ok? Any issues in doing that, which might affect the power transformer?
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Brad, you can put a power resistor in parallel to bring the value in line with requirements.
Yes you might want a bit higher value, maybe 2000 ohm as the resultant from the parallelling.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Brad;
Try looking through some of the U.S Radio and TV schematics, some of the Phonola sets from that era are Kitchener built clones of those sets, I have one that is basically a gothic Gloritone in a slightly different cabinet, and says "Dictator" on the escutcheon rather then "Gloritone".
Regards
Arran
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