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tone control
#5

It is easy, but it will modify your radio so that it no longer has the original volume and tone circuitry.

You will need a 1 or 2 meg. volume control, and it must have a bass compensation tap. One pulled from a 41-280 will work quite nicely. You will also need the tone control potentiometer from the same 41-280 or similar.

You will remove the old two-position tone switch and replace it with the 6 megohm tone control potentiometer. The original volume control gets replaced by the 41-280 volume control.

Connect a 68K resistor from the volume control tap to the low end of the tone control potentiometer, and a .0047 uF cap from the low end of the tone control potentiometer to ground.

Connect the center (wiper arm) terminal of the tone control potentiometer to ground.

Now connect a .0068 uF cap from the high side of the tone control potentiometer to the plate of the "det. amplifier" tube, a 44.

You can see the actual circuitry by looking at a 41-280 schematic, although the values of the added resistor and two caps are different from those shown in the 41-280 schematic.

This hot-rod circuit will make your 71 sound like a big console radio - but, as I said, it isn't original!

I did this to my "Super" 71 because it was a rust bucket to begin with, a chassis that some people might have just tossed out.
http://www.philcoradio.com/notebook/super71.htm

I would not do this to a good chassis, but that's just the way I am. I prefer to keep the good stuff original; but I am not opposed to experimenting on junk sets.

--
Ron Ramirez
Ferdinand IN


Messages In This Thread
tone control - by ipwizard - 10-19-2011, 11:43 PM
Re: tone control - by codefox1 - 10-20-2011, 07:48 AM
Re: tone control - by Ron Ramirez - 10-20-2011, 08:24 AM
Re: tone control - by ipwizard - 10-20-2011, 02:55 PM
Re: tone control - by Ron Ramirez - 10-20-2011, 05:00 PM
Re: tone control - by ipwizard - 10-20-2011, 05:06 PM



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