WEM Rush Pep Box Silicon Fuzz.

[digi2t]

I'm starting this thread following a request by Mark Hammer on my Project V thread.

I did a little research, and I've found a schematic, two actually, but it needs to be verified. There were two versions of the Pep Fuzz, germanium, and silicon. The one Mark spotted on Youtube ( http://www.youtube.com/watch?v=AWxS60-U0os ) is the silicon version. This is what I found on the silicon version;



Two different gutshots of silicon versions;





Possible parts list?

C1: 12.5µF electrolytic
C2: 12.5 µF electrolytic
C3: 0.01µF, styroflex
C4: ?, styroflex, larger physical size than C3
R1: 1M
R2: 1k5
R3: 100Ω
R4: 10k
P1 (trimpot): replaces 56k resistor; possibly 100k
pep pot: 10k log
volume pot: 50k log
q1: BC107 (or BC109C)
q2: BC107



Here is what I found on the germanium model;



Note that the EFFECT pot is wired differently on the two schematics. Both versions might be wired as per the germ schematic, but I'm not sure.

Personally, I'm not too interested in the germ model. The silicon one sounds pretty good to me though. My bread board is occupied at the moment, so if anyone wants to test this stuff, give it a go. I might play with it at some point.

Hope this helps you out Mark 

Cheers,
Dino

[Mark Hammer]

gaussmarkov sent me a PDF of an article on the history of the Rush Pep box, several years ago, the description of which can be found here: http://www.leonardo.info/isast/journal/toclmj17.html

The curious name of the unit comes from its designer, one Pepe Rush.  It was purportedly designed in 1965 or so.  Apparently, the Beatles had two of them (it may or may not have found its way onto "Revolver", specifically on "Tomorrow Never Knows"), and the heavy psychedelic Edgar Broughton Band also used one.  The article notes:

Again at an unspecified date, likely,
however, to have been in the late 1960s,
Rush was approached by Charlie Watkins,
co-founder of Watkins Electric Music
(WEM), famous for the Watkins Copicat
Echo. WEM took over the marketing of
the Rush Pep Box and modified it using
silicon transistors. The standard model
sold for 12 guineas (£12, 12 shillings),
with a bass model priced slightly higher
[11]. The deal foundered, however, when
a Watkins engineer incorporated the
pedal into an amplifier. A dispute over
royalties ensued, and Rush lost control of
his own invention. Recent plans to redesign
and launch a new version of the
Rush Pep Box are still in abeyance.