[HBR] Pullen mixer

[Walt Hutchens]

Donald posted:

> I am now a believer.  All the things they say about the Pullen are
> true---and all it took was three resistors added to Walt's dual triode
> circuit!  I must say that the Plate voltage ratio is critical--it will make
> the difference between no signal and Grins and Giggles-but a pot in a
> voltage divider circuit to feed the second grid, and just tune for the best
> output......for the 6gm8, I have 20volts on plate 1 and only 2.2 on plate.

Looks like you've found something that works.

I had written some of a post on mixers in general and triode mixers in
particular but none of it would be really new: "It depends on what you're
trying to do" ... 

I'll say only this: A (first) mixer implies a receiver and also the reverse.
Thus a 6GM8 in a Pullen circuit tweaked for maximum output at a very low
plate supply voltage implies certain kinds of circuits and operating
conditions on both sides.

Neither a lawnmower engine in a Maseratti or the reverse would be very
satisfactory.  So too with most of the circuits in a communications
receiver.   The challenge is to picture the entire mower when you are
building the engine and keep that vision in mind as you move from working on
the engine to the mower deck, the gas tank ...

You're working on a different lawnmower than I am and your vision for the
mixer is somewhat unlike mine.

Walt
KJ4KV