Volume Control for Philco 620 - Printable Version

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+--- Thread: Volume Control for Philco 620 (/showthread.php?tid=206)

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Volume Control for Philco 620 - Derek D - 01-10-2006

I need to find a suitable on/off/volume control for my 620 rebuild. The original was replaced with an incorrect part. The original part is 33-5105. I believe it is a 1 Meg part with a 225K tap. Does anyone know where I can locate a replacement? I would like to find a working original if possible.

I see that AES sells 1 Meg switched pots, but they don't list any info about a tap. What is the tap used for? I take it that is a fixed resistance used for something other than for volume control?

Thanks.

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- Chuck Schwark - 01-10-2006

Contact Mark Oppat - moppat AT comcast DOT net

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- Terry Burns - 01-10-2006

Hi Derek,

The tap is used for bass compensastion at lower volumes. It's tapped at the lower end of the volume control with a cap and at low volumes it has a tendency to shunt the high frequencies to ground. On higher volumes it has little or no effect You can go without it if need be or order one. Some folks say it makes a difference some say it does'nt. The circuit will work without it.

Hope this helps
Terry

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- Derek D - 01-12-2006

Thanks Chuck, I'll send Mark and email.

Terry, Thanks for explaining the circuit. That helps a lot.

Derek

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