Mastotron Pulse width control?

[ReeceAblaze]

Hello everyone.

My friend has asked if I can build him a mastotron and I have been looking at the circuit. How does the pulse width control actually work? Just curious tbh

[PRR]

It changes the overall mis-bias to change the symmetry of the clipping.

[soggybag]

Rumor has it that the transistors need to be lowish gain to get the PW to work correctly.

The numbers I've read are in the range of 170 to 200 hfe.

The same is true for the Woolly Mammoth. This uses 2n3904 which come in low gain and higher gain values. I think the Mastotron switched to 2n2222 because these are more reliably in the lower gain range that makes the PW work.

[ReeceAblaze]

I have both 2n2222a transistors and and 2n3904 transistors. After building this mastotron I might build myself a woolly mammoth

[ReeceAblaze]

It changes the overall mis-bias to change the symmetry of the clipping.

So by adding more resistance to that feedback loop you get more symmetrical or less?