08-14-2007, 09:12 PM
It may make the purists irate, but here's an addition to your Philco Frankenradio-
An extremely simple LED tuning indicator for the 1937 series - an LED in series with a 150K ohm resistor to ground; the other end of the LED connects to pin 1 of the 6Q7 AGC detector. You may want to adjust the resistor value; also a cap across the LED might improve it a bit.
DO NOT connect your LED/resistor to the AGC feedback line; doing so will cause distortion and a loss of sensitivity.
An extremely simple LED tuning indicator for the 1937 series - an LED in series with a 150K ohm resistor to ground; the other end of the LED connects to pin 1 of the 6Q7 AGC detector. You may want to adjust the resistor value; also a cap across the LED might improve it a bit.
DO NOT connect your LED/resistor to the AGC feedback line; doing so will cause distortion and a loss of sensitivity.
Pete AI2V
