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Philco 77 volume control - Printable Version

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RE: Philco 77 volume control - Ron Ramirez - 05-02-2012

I doubt if you'll find a 1750 ohm rheostat. I wouldn't be afraid to try 1800 or even 2000 ohms.

RE: Philco 77 volume control - morzh - 05-02-2012

2000 Ohms is fine - actually this is what's quoted in the Rider's for it.

Bigger wattage is always OK, as long as you can fit it.

You cannot venture too far in the larger impedance area - it will screw up both 224 tubes Cathodes' potentials, especially the 2nd one.

RE: Philco 77 volume control - Ron Ramirez - 05-02-2012

Personally, I think Terry's (7estatdef) idea has great merit; however, I must add that converting a 65 to operate with AVC is not a project for the novice. I would try it if it were mine.

RE: Philco 77 volume control - kenlew0405 - 05-02-2012

How about something like this?

http://www.ebay.com/itm/220560054014?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

-Ken


RE: Philco 77 volume control - morzh - 05-02-2012

If they fit the size, I think you can use them. There will be a little less regulation but you may not notice it that much.

PS. Ohmite still makes those, but for the price you can't beat this Russian deal of yours. And , in my experience, Russian military components are (were that is) very good. They no longer make'em, they buy Chinese.

http://www.mouser.com/Passive-Components/PotentiometersTrimmers-Rheostats/Rheostats/_/N-9q0yj?P=1z0vkonZ1z0vkos&Keyword=wirewound+rheostat&FS=True

PPS. You can add a 200 Ohm 2W resistor on either end (to keep the voltages accurate) in series (to bring the total to 1.7K), and see where it works the best, and leave it there.

RE: Philco 77 volume control - kenlew0405 - 05-16-2012

Thanks for all your great advice everyone! I put in the Russian surplus rheostat and it works great! I'm now in the process of stripping the body with Citristrip , which works great and you can use it indoors.

Thanks again,
Ken