VK Booster

[mac]

I tried the idea in this link:

http://www.diystompboxes.com/smfforum/index.php?topic=59911.20

I started with a simple booster to hear what it does.



In the above thread, there is a link to a patent where it is discussed the ratio "drain voltage to diode forward drop". The higher the ratio the better, 66 tube-like. As the patent and VK article differ a little, I'm not sure if this ratio is valid in VK design. Anyway I chose a 1N5819 Schottky, Vfd=0.150V, for this reason.
In my breadboard drain voltage was 6v, or 3V from gnd. At this voltage output volume was maximized. And Vd/Vfd=40.
The effect of the diode is noticeable, kind of compression. Just disconnect it and re-adjust drain resistor.
VK article has a lot of maths and a spreadsheet to find optimal values. I guess a trimmer instead of the 2 source resistors is a better solution for lazy people like me.

mac