In the realms of solid state overdrive pedals a lot of contenders claim to be “tube like” and have that tone which only a true vacuum tube can provide. However, few actually deliver on that promise. After having played around with the Blackstone Appliances Mosfet Overdrive circuit I can safely say – it sounds damn good! Certainly tube like and very responsive. This is partially to do with the CMOS inverters found in the circuit design (Which is where the mosfets come in, within each inverter stage are two mosfets 😉 For those that were wondering) but is also partially to do with the interesting use of the front end opamp gain stage.
For anyone looking for a different tone than the standard tubescreamer I’d recommend you give one of these things a go! Check out the youtube demo, I love the tone;
Here’s a schematic drawn by RipDivot; http://www.mediafire.com/?eqs17owjkdf8kip
And here is RipDivot’s excellent vero layout;
For a great PCB layout check out Madbean’s Mysterioso ; http://www.madbeanpedals.com/projects/MysteriosoJR/docs/Mysterioso_JR_ver2.pdf
Here are some images of a great build done by MichP –
