Fredric Effects Utility Perkolator 15th February 2009

Spent a little while this weekend breadboarding the Harmonic Percolator circuit with trimmers in place of various resistors to try some stuff out and rebias the circuit for the various soviet transistors I've got. Using a 3PDT switch to A/B the transistors is a great tip I picked-up from the excellent Beavis Audio site. As it turns out, very little needed to be changed and the margin of error for lots of components in this circuit is so big that I slotted in a GT313A and 2N3904 in place of the specified PNP germanium and NPN silicon transistors and the result is still discernably an HP, albiet slightly gainier and more unruly. The USSR parts used to make this effect also result in 15% more mojo arrows than a normal Harmonic Percolator. This is what I'm calling the Utility Perkolator.



L-R: Modified EA tremolo with pulsing blue LED and awesome tiki-style fabric finish, Utility Perkolator prototype (future ones will be khaki fabric), Green/white HP, Grumblier Wolf.