Category: Effects

Single-Tube add-on Reverb


One day I dug through my pile of salvaged transformers and came across an interesting little piece. It’s an inter-stage percussion transformer from a Hammond M3 organ, part A0-24113-0. It is listed as T5 in the AO67, M100, and other circuits. It’s about 1.5″ x 2″, not very big. Hammond used it as an inter-stage signal transformer that also coupled in a low-impedance signal on a third winding. Everyone who has ever scrapped a Hammond organ has one of these sitting around, so there are plenty of them out there for cheap or free. I fed it a little AC...

Dallas Arbiter Fuzz Face (NPN Silicon)

sili fuzz 1

My friend’s dad picked up this Dallas Arbiter Fuzz Face new in 1976. It came as an NPN silicon circuit with BC209 transistors, and after 30 years of component drift it sounded downright horrible. He tried gutting the thing and shoving a Boss SD-1 board inside, but that didn’t work out. By the time the thing got to me it was a beaten chassis with no back plate, extra holes drilled in the front, all jacks, pots and switches missing, and a broken indicator LED. The original circuit board was there but it was a lost cause.

LesVerb – A 12FQ8-based “ReVibe”

LesVerb schem v0.2

Once upon a time a guy on TDPRI pulled a boatload of 12FQ8 tubes from a Wurlitzer organ. They’re pretty odd tubes – Think of it like a 12AX7 with both cathodes tied together, and each triode has not 1, but 2 plates! He graciously sent me a half-dozen to experiment with. This is one of the projects that spawned from my experimentation.

Weber ReVibe Reverb Unit

revibe top

The idea behind the Revibe is brilliant: Take a standalone reverb unit and add the two-phase “harmonic vibrato” found in the 6G12 Concert. I first built this Revibe in 2010. I bought the fiberboard and power transformer from Weber, and used my own components for everything else. I modified the layout to fit a narrower chassis by relocating the power filtration section to a ‘doghouse’, but all the fundamental orientations remained the same as stock.