Philco 650 K-17 Speaker Transformer - Printable Version

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+--- Thread: Philco 650 K-17 Speaker Transformer (/showthread.php?tid=19260)

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Philco 650 K-17 Speaker Transformer - wardmc1 - 11-20-2018

Hello Everyone,
I am having issues with a K-17 speaker. The output transformer was bad and I need to replace it. I'm having trouble crossing the 32-7078 transformer. I bought a Hammonds 125D universal push-pull, but and not sure how to wire it up. Anybody have experience with this and can point me in the right direction?

Thank You in advance.

Matt

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RE: Philco 650 K-17 Speaker Transformer - morzh - 11-20-2018

You have 10,000 kOhm to 1.11 Ohm transformer, which means you have the ratio of 95 of I:II windings. The impedance at 1.5 ohms should be 13,636 so the closest you get is by connecting your speaker between 3 and 4 of the secondary.

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RE: Philco 650 K-17 Speaker Transformer - Radioroslyn - 11-20-2018

Hmmmm
The push/pull triode connected 42's w/fixed bias p to p load is 6K sez my '40 RCA tube manual and spec on the original transformer is 5.9K. With that in mind I would go w/ 1 and 3. Rca sez it will make abt 10watts @ 2% distortion. Wired as penodes they will abt twice the audio power but almost triple the distortion.
YMMV

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RE: Philco 650 K-17 Speaker Transformer - morzh - 11-20-2018

I think you are right. I didn't look much at the output stage, it seems to be direct-biased triode connection (cathode biased triode is still 10K) which is 6K.

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RE: Philco 650 K-17 Speaker Transformer - Radioroslyn - 11-21-2018

>I think you are right.
I try!

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