The very first
Whizzer was designed and built by Sal Trentino for
the Rust Never Sleeps tour in 1978. It was analog, not digital, and
controlled one Fender amp knob, the Volume control. When the switch
was pressed on Neil's red footswitch it would turn the knob to one of the
the two preset positions. Each press of the switch
would cause the Whizzer to go to the alternate position. The electronics were a couple
of comparators that could be preset using
potentiometers to set a voltage from which Neil
could select one position or the other. That in turn
fed an opamp which controlled a DC motor that would
then run the motor clockwise or counter-clockwise
until the comparators were at a null at which point the motor
would stop. It was coupled to the Fender Vol. knob
with a long flexible shaft coupler. It was an
elegantly simple solution and I have a
photo of Sal's version. Unfortunately Sal passed away in
March 2009. He was one of Neil's most highly regarded techs.
In 1991 Neil
asked me if I could design and build a Whizzer that could control all
three knobs and have multiple positions memorized
for the various "Neil sounds" he could
call up with
his footswitch controlling his Fender Deluxe amp
while playing live or recording. I said I could.
There are two
Whizzer versions, the copper one and the brass one.
The copper is the first one I designed and built
using discrete CMOS logic as I was worried that
using a microprocessor on equipment so closely
coupled to Neil's amp would allow a digital
clock, which drives a microprocessor, to get into
the audio. That audio signal path is very
susceptible to hum and noise with all the gain in
the high impedance circuit between Old Black, his
guitar, and the Fender Deluxe amp. The brass version
was built about a year after the copper version as a
backup or standby unit, in case of failure in the
copper one. Rock and roll being notoriously hard on
The copper one
is shown in Tom Wheeler's book [at right] sitting on the amp, but the interior shot
is of the brass one which does use a microprocessor. There
is a shot of the interior of the copper version at
the bottom of this page. As you can see the micro is
much simpler and cleaner design. All that logic is
done inside one chip by software.
metal work was designed by me and is meant to echo or suggest a
steam locomotive with the blinders that some of them had back in the
1930's and 40's. As you may know Neil is HUGELY
into trains. I also had something of a vision of old timey radios in
mind. The metal work was done by Bart Lewis of Lewis Metal Products
in San Francisco. They, he and his wife Judy, also did the
work on a console I designed and built for Neil back in 1977. Bart
and Judy Lewis were truly artists with metal and I was very fortunate
to have hooked up with them.
version made it's debut on the Weld album and tour.
power-up the Whizzer defaults to switch position 1 and the
values stored in memory, spinning the amp knobs to those
presets. If a knob on the front panel is turned the values from
memory are overridden [but not lost] by the new count values and
the motors whiz the amp knobs to the new setting. If Neil wants
to overwrite what is in memory with this new setting he simple
presses the ARM and WRITE
pushbuttons on the right side of the display and the new value
is stored. The memory is non-volatile meaning it retains its
data with power removed.
pushbuttons to the left of the 3 knobs are a
NORMAL / LOCK function which when locked, prohibit
the knobs from changing anything. A protection against possible
vibration or accidental changes. The four preset buttons
continue to work however. The other pushbutton calls up previous
values stored in memory in a case where you change your mind and
want the old value[s] back.
pushbuttons on top are in parallel with the four footswitch
pushbuttons so he can select the settings locally.
display readouts go from 0.0 to 12.0,
since the knobs on the Fender Deluxe go from 0 to 12. The 3
LED's above the these display readouts turn ON
when that setting is NOT at a memorized
backside there are four 1/4" phone jacks which are wired one
each to a set of relay contacts so when he selects a preset the
corresponding relay contacts close which allow control of other
effects, including special effects, lights, pyrotechnics, etc.
To my knowledge these have never been used.
the copper version as it is all discreet CMOS
digital. The electronic design was started by
another employee of mine Jerry Elmer, however he left the company
before it was finished. So I took over and completed the
design and made the changes necessary to realize a design that met
circuits described are in triplicate, one for each knob.
system is as follows: The three black knobs on the front panel
are actually digital encoders which put out biphase pulses 90˚
apart. This tells the logic which way the knob is being rotated.
The pulses are fed into up/down counters that are controlled by
magnitude comparators which limit the count to a minimum of zero
and a maximum of 120 giving Neil 120 increments he can set into
memory. Zero into counter translates to a knob on the Deluxe amp
being fully counter-clockwise and 120 corresponding to fully
clockwise. This range sets the limits for the
digital-to-analog converters [DAC's] which drive the servomotors
and the Deluxe knobs.
up/down counters take the serial pulses in and output a parallel
8 bit digital 'word', of which only 7 bits are used. This 7 bit
word is the fed to a latching tri-state line driver, the output
of which is a digital 7 bit bus. The tri-state drivers are able
to disappear from the bus by going into a high impedance state.
It is this bus that feeds the DAC's with the digital word value
which the DAC converts to a DC voltage that is fed to the
servomotor driver chip, a Motorola MC-33030P.
for the tri-state drivers is that the EEPROM that holds the
memorized positions is also attached to this bus. The logic
employed determines which driver is active, the memory or the
front panel knob [encoder]. So normally the data from the EEPROM
is being read into the DAC but if Neil touches a knob it
immediately tri-states the memory and the knob now becomes
active and feeds the DAC. It will remain in this state until one
of the 4 preset buttons is pressed, recalling the memory
mentioned the three DAC outputs are fed to three MC-33030P IC's,
one for each motor. These motors are made by ETI and are geared
way down to one revolution per second. This has the added plus
of increasing the torque of the system. These servomotor
assemblies also include a potentiometer which give the MC-33030
feedback as to it position, and it has an adjustable clutch
mechanism which protects the pots in the Deluxe amplifier from
being damaged if the motor should run beyond the amp pots travel
range. If that should happen, the motor will continue to spin
but the clutch will slip so no harm will come to the amp
back of the Whizzer there are 3 sets of 2 holes. These are to
allow calibration of the DAC's without removing the top cover.
Inside are 10 turn pots which set the minimum and maximum for
the DAC travel voltage range to the MC-33030.
the rear there are two circular connectors. One supplies +5
volts and +12 volts DC to power everything. The power supply for
the Whizzers is in a separate box. The other is connected to the
footswitch and carries all the logic signals. There is a small
circuit board in the footswitches that have balanced line
drivers for noise immunity in the long cable.
footswitches you will see two circular connectors. One connects
to the Whizzer and the other to the rest of Neil's Rig which has
other effects, which I won't go into. The first four pushbuttons
on the lower row, left to right, call up the Whizzers four
In the brass version
the logic is all done in software, written by Joe Thibodeau
when he was working for me at my company Real Design
Labs, Inc. The brass one is built around a Motorola
MC-64HC11 microprocessor as it had all the ins and outs to
handle all the knobs, memory, servomotor
driver and display functions.
It turns out we over dedicated it to the point where
it won't track the knobs on the Whizzer [not the
amp] because it's doing so many jobs it can't keep
up if the knob is turned too fast. Joe did a hellava
job getting all those functions to work in real time in one
micro. What we really
should have done is have one micro for each of the
three amp knobs and that would have solved the
problem. Actually now that I think about it I
believe that's how Joe wanted to do it in the first place but I
wanted it in one micro - I don't remember why. In the end he was
And I need to give credit to
another Joe, Joe Cynarowicz
who actually built the PC board and electrical for
the brass version and did a beautiful job, as you
pretty much it.
If you have questions, contact me
World Tour Rehearsal Setup
at Fox Theater in Oakland June 10, 2014
Jeff Pinn Setting up Whizzer
Neil's Guitar Tech Checking Out
the Red and Black Footswitches