02-02-2014, 08:25 PM
A note:
Measured that inductance in the RF filter in the 2nd detector in the plate circuit. I was interested in it because it should be the same as in 90's detector and I did not know the value.
Well, for those interested: it is 11mH and the DC resistance is 100 Ohm.
The L-meter also gives me Q factor equal about 21 (not that I think it is important here).
As for the plate detector circuit itself, I wonder why Philco variated some values so much. They might not even be important values, but I always thought reusing the values is a good thing, cuts the inventory down.
For instance, in the 90 using the same tube and, I presume, close plate power voltages, the resistor for the screen grid of the 2nd detector is 250K which is then filtered by a fairly large cap.
In 70 the exact same screen grid in practically the same plate detector is 250 Ohm, and then also filtered by a cap of the same order of value.
I did not have 250 Ohms resistor and I do not think it matters so I simply put 1K there or something.
Measured that inductance in the RF filter in the 2nd detector in the plate circuit. I was interested in it because it should be the same as in 90's detector and I did not know the value.
Well, for those interested: it is 11mH and the DC resistance is 100 Ohm.
The L-meter also gives me Q factor equal about 21 (not that I think it is important here).
As for the plate detector circuit itself, I wonder why Philco variated some values so much. They might not even be important values, but I always thought reusing the values is a good thing, cuts the inventory down.
For instance, in the 90 using the same tube and, I presume, close plate power voltages, the resistor for the screen grid of the 2nd detector is 250K which is then filtered by a fairly large cap.
In 70 the exact same screen grid in practically the same plate detector is 250 Ohm, and then also filtered by a cap of the same order of value.
I did not have 250 Ohms resistor and I do not think it matters so I simply put 1K there or something.
