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Old 08-14-2018, 08:58 AM
Tom9589 Tom9589 is offline
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I took a look at the schematic for this Philco and noticed something I had never seen previously. The filament windings for the two LV rectifiers (5V3 and 5U4) are center tapped and the B+ is taken from the center taps.

What is the purpose of taking the B+ from the center taps?
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Old 08-14-2018, 11:00 AM
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Electronic M Electronic M is offline
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Quote:
Originally Posted by Tom9589 View Post
I took a look at the schematic for this Philco and noticed something I had never seen previously. The filament windings for the two LV rectifiers (5V3 and 5U4) are center tapped and the B+ is taken from the center taps.

What is the purpose of taking the B+ from the center taps?
Most likely to reduce hum pickup from the filament winding.
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Old 08-14-2018, 11:16 AM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Tom9589 View Post
I took a look at the schematic for this Philco and noticed something I had never seen previously. The filament windings for the two LV rectifiers (5V3 and 5U4) are center tapped and the B+ is taken from the center taps.

What is the purpose of taking the B+ from the center taps?
They always did it that way when the rectifier tube socket was part of the transformer. It was easier for the transformer manufacturer to do it that way.
The Admiral 20Y1 and the Muntz chassis did it that way.

Last edited by dieseljeep; 08-14-2018 at 11:22 AM. Reason: Wrong about the early Philco radios
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