The Gleeman Pentaphonic
by Joey Swails (j.swails@comcast.net)

The Gleeman Pentaphonic was introduced in 1981 by the Gleeman company, 
a partnership of two brothers, Bob and Al Gleeman. They were based (in 
the grand old Silicon Valley tradition) in their garage in Mountain 
View, California.

I met Bob Gleeman at the 1982 AES show in Anaheim, while I worked for 
Don Wehr's Music City in San Francisco. I was blown away by the 
Pentaphonic's sound; Bob came around the store a soon after, and we 
became the first authorized Gleeman dealer.

The story goes that the Pentaphonic came about when Bob decided that he 
wanted a synthesizer like a Prophet-5, but smaller and more portable. 
His "smarter brother" Al, a computer hardware designer, basically 
designed the synth from the ground up, working from his brother's 
description of what a polyphonic synthesizer should do.

It was in actually a digital/analog hybrid -- the filters and amps were 
based on the same Curtis chips that were used in the Prophet, ARP and 
Octave machines. The oscillators were digital, as were the ADSRs. The 
machine was based on the Intel 80186 microprocessor, which was very 
advanced for it's time. In fact, it used two 80186's -- one for the 
keyboard/transpose functions, the other for waveform and amplitude 
control. One thing led to another and they decided to try to market the 
machine after everyone who heard it told them how great it sounded. 
They had wanted to call it the "Gleeman Minstrel", since their family 
name Gleeman means "minstrel." But there was another machine on the 
market called Minstrel (the Basyn, by Grey Labs), so they settled on 
"Pentaphonic".

The oscillator section featured 3 oscillators, each with a selection of 
8 waveforms. The waveshapes were fixed, in that there was no 
pulse-width modulation. Instead it offered 3 choices of pulse widths. 
There were two "digital" waveforms with lots of high, bell-like 
overtones which had a distinctive, almost FM-like sound when selected.

There was an octave switch on each oscillator (hi/low) and a "chorus" 
switch that actually detuned oscillators 2 and 3. Interval tuning of 
the oscillators was not introduced until the programmable version was 
made, and the intervals were part of the program, selected by pressing 
keys on the keyboard. There was also a Transpose control that shifted 
the entire tuning of the machine in half-steps over a one octave range.

It was a standard Prophet-type control set, with one filter ADSR and 
one volume ADSR. The filter section had the standard cutoff, contour 
amount and resonance dials. The layout was basically that of a 
MiniMoog, including an oscillator mixer that included a pink noise 
control.

One drawback was a lack of a keyboard tracking filter setting, which 
was explained to me as being impossible due to the way the keyboard 
controlled the oscillators. Another was that it also lacked a provision 
for a sustain pedal.

The keyboard system was unique in that it was not based on the same 
serial-scanning system developed by Tom Oberhiem used by virtually 
every polyphonic synth, but was rather a parallel port that had an 
input point for each of the 37 keys. This made for a very fast, 
responsive keyboard, but made it difficult to derive an analog voltage 
to use for filter tracking.

The first Pentaphonic's joystick was only a pitch bend lever, but later 
they upgraded it to allow for pitch bending and modulation of either 
the pitch or filter cutoff. There was also a simple, real time, 
one-track sequencer built in, but with the unique feature of being able 
to play back the sequence while playing the keyboard with the joystick 
and transpose control effecting only the notes played on the keyboard.

The original Gleeman Pentaphonic retailed for US$2795 and featured a 
6X9 inch "car speaker" with amplifier built into the back of the 
cabinet. The price included an injection molded road case (actually a 
Samsonite suitcase customized with form-fit molding inside to hold the 
synth and a "Gleeman" nameplate glued over the "Samsonite" label.)

In 1982, the programmable version was introduced. I had told Bob from 
the beginning how much better (and more marketable) the Pentaphonic 
would be if it were programmable (as the Prophet-5 was setting the 
standard for analog synths in these days.) The "Presetter" used a 
two-digit thumbwheel selector next to the joystick with a toggle 
switch. The first 50 programs (designed by the Gleemans with help from 
myself and Keith Hildebrant, who later worked for Opcode and authored 
several sound sample disks) were in ROM memory and the second 50 were 
user programmable. The toggle switch allowed for either instant recall 
as the thumbwheels were changed, or in the second position the patch 
remained in performance memory until the wheels were changed and the 
switch was toggled into the "recall" position. A small recessed red 
button was the "write" switch. Unfortunately there was no provision for 
off-loading of programs. The programmable version retailed for US$3295.

I sold Oscar Petersen his Pentaphonic a few months after we became a 
dealer. He was playing a concert in town nearby and came into the store 
just to kill time after the soundcheck. He started playing on the 
Pentaphonic and didn't stop for two hours, while a small crowd gather 
to listen. He told his road manager he had to have one, and Bob and I 
delivered it to him at the venue the next day.

The greatest thing about the Gleeman was the sound -- it was gorgeous! 
The pads were thick and rich; the string patches made an OBXa sound 
almost thin by comparison. The three oscillator sound was very similar 
to a MemoryMoog in some ways, but with a crystal clarity that the Moog 
couldn't touch. If it had a weak point, it was that the Gleeman was 
almost TOO "pretty" sounding -- not a very good "down and dirty" synth. 
It was no good at the kind of bizarre patches that the Moog and the 
Prophet were capable of. It lacked a sync mode and the limited keyboard 
range was a hassle, but within that range, it was a truly lovely 
sounding instrument.

To address these defects, the Gleeman brothers had plans for a 61-note, 
touch sensitive, 8-voice version of the synth (I even saw the prototype 
being built while visiting their workshop). MIDI was just becoming 
available, and the new machine would have MIDI (though by then 
programmable Pentaphonics could be retrofitted for MIDI by the shop.)

Unfortunately, by 1984 the Japanese synth builders were flooding the 
market with inexpensive polysynths (like the PolySix and the Juno 6/60) 
and the market for a 5-voice machine with a 37-note keyboard and a 
price tag over 3000 bucks was gone. And soon after that the DX7 was 
introduced and the market was radically changed. The Gleeman 
"Octophonic" never saw the light of day, and the Gleeman brothers 
retired from the synthesizer business. (I heard that years later Al 
Gleeman went on to invent the laser dentist's drill.) Only 50 or so 
Pentaphonics were ever made but they still pop up in the keyboard rigs 
of some major recording artists such as Kansas, The Band, R.E.M. and of 
course, Oscar Petersen.

But the Gleeman didn't disappear until after it had made a bit of a 
stir in the synth world with the introduction of the world's only 
see-through synthesizer -- the "Pentaphonic Clear".


The Pentaphonic Clear

All right, I'll admit it -- the Pentaphonic Clear was my idea. Sort of. 
Really. It happened like this:

Keith Hildebrant loved the Pentaphonic but wanted a "portable" keyboard 
(like the Prophet Remote)he could strap over the shoulder.

So I got the Gleemans to take Keith's standard Pentaphonic, remove the 
keyboard and build a separate box to hold it with a detachable 
multi-pin connector cable. After consulting with me and Keith, they 
made the remote case out of a sheet of clear plexiglass, sawed and 
glued together into a rectangular box. The gap left in the body of the 
original synth was merely covered with a sheet of black plastic. As far 
as I know, it was the only one ever made.

But the clear plastic keyboard remote looked very cool! Keith installed 
some tiny "tivoli" lights into it for maximum flashiness. When they 
delivered the finished machine, and commenting how cool a clear box 
looked, I suggested that a totally clear case on a standard Pentaphonic 
would be a really snazzy looking machine. (I was inspired by seeing 
Ultravox on stage where the drummer had a CR-70 drum machine built into 
a clear plexi case with blinking lights in it.) Bob had also seen an ad 
put out by Sequential for the Pro-One which they had built a custom 
clear plastic case for it (they used it as a novelty item to display at 
trade shows.) The Gleemans liked the idea and decided to run with it.

The Clear model was functionally identical to the original black, 
except the idea was to make it so that it would be feasible to wear the 
thing around one's neck like an accordion (which it was roughly the 
size and shape of anyway.) To this end, the speaker and it's power amp 
was eliminated, and the power supply was removed and placed in a small 
separate steel box with a multipin connector cable to carry power to 
the machine. The audio output jack was also placed in the outboard box, 
so the player only had the single cable trailing behind them to trip 
over.

The Clear's case was made of Lexan plastic instead of Plexiglas, and 
was lit from inside by small tivoli lights. The knobs were clear 
Plexiglas balls, with set screws in them that served as the pointers. I 
was the first person besides Bob and Al to see a Clear, and it was a 
real head-turner in my keyboard shop. No other machine ever looked 
quite like it, and the Pentaphonic enjoyed a slight revival in sales 
before it's ultimate demise. Many major keyboard artists boast of 
having one of those "cool, clear little synthesizers" and they still 
pop up in keyboard rigs on stage and video. You can't miss it.