[HAM] Hammond C3 to Marshall amp

[William Mark Bristow]

I've high-powered several Leslies and regularly play with 2 Bill Beer 122's
bi-amped at 180 watts with JBL drivers -- experience shows they will handle
a 10,000 seat auditorium.

For the Marshall 100 w head I would use one of the new Ferro-fluid Leslie
Treble Drivers -- they are great.  They are rated at 100 watts at 16 ohms.
You can get one of the new 15" bass speakers from Leslie - they are rated at
100 watts and are 16 ohms then you should be able to use the original
crossover.  The components are available at www.goffprof.com or call
Hammond-Suzuki for a dealer near you.  (I have run an original crossover
from a 1970 Leslie 122 with a 100 watt amp.)  This new treble driver has a
very similar rolloff above 6000 hz just like the old Leslie drivers so it
produces a similar sound.  If you want other drivers, remember the Hammond
sound needs a sharp rolloff above 6000 or they sound really shrill and tinny
(though some like it).  You'll do better with a driver with a phenolic
diaphram - which the original Leslie drivers had.  If you go 8 ohm speakers,
you'll need an 8 ohm crossover - the Leslies cross at 800 hz with a 12db per
octove rolloff.

You'll need to rig up a converter from the six-pin 147 hookup to Marshall
amp with a 120 volt single pole double throw relay and a/c plugs to switch
the motors.

www.captain-foldback.com has Uncle Harvey's Leslie Pinout guide and you can
see the Leslie 147 hookup.

It's something like:  (1 & 6 may be opposite -- check the pinout guide - I
can't remember which is which)  PLEASE NOTE:  THERE IS 120 AC volts on pins
2,3,4,5 of this CABLE and it CAN KILL!!!
1 - signal
2 - 120 volt relay switching
3 - a/c 120 volts to speaker
4 - a/c 120 volts to speaker
5 - 120 volt relay switching
6 - signal ground

Although your C3 produced a push-pull (balanced) signal with ground and "G -
G" terminals much like a low impedance XLR mic cable with ground (x), signal
(L) or positive signal, and signal (R) negative signal - The 147 uses a
single-ended or unbalanced signal just like the 1/4" male jack pluging into
the Marshall from a guitar.  The audio is obtained by picking up JUST ONE of
the "G" terminals and ground which is what the 147 hookup uses.  HOWEVER:
the Hammond produces a VERY high gain signal - so if the Marshall has a
high-gain input use that.

Your Marshall (even with tubes) will probably produce a much harder, less
warm sound than the original stock amp - but so do my Bill Beer Leslies
which are the sound you hear on SANTANA or Fleetwood Mac or Eric Clapton.
Some like it, some don't.  I do, and since I sometimes play in very large
venues or in outdoor settings and don't want to carry six Leslies - I opt
for the high-power.  Unfortunately Bill Beer has died, and his high-power
Leslie amps have pretty much died with him and the schematics were secret.
My Leslies use a JBL 2482 (with throat adaptor) treble driver 16 ohm, and an
8 ohm JBL E-140 bass.  They are bi-amped with 100 watts bass and 80 watts
treble.  The volume is from 1 - 10 like a standard Leslie and if you play
them at volume settings over "7" and are sitting within 20 feet of them,
you'll permanently damage your hearing.  Once in a while a Bill Beer Leslie
comes for sale on Ebay or the trade papers of a large city.  They are very
well built and his amps are almost indestructible - but a tech has to
reverse engineer them to work on them.  If you like the sound, and many do,
they out-scream any Leslie I have heard to date.

Hope this helps,
Mark Bristow

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