Persimmon Circuits - Construction of the Persimmon Synthesizer

The PERSIMMON SYNTHESIZER

Late to bloom but a taste worth the wait.

PROJECT BEGINS

In the beginning in March of 2004 I went to work refurbishing my Sound Machines sometimes called (Frankenstein Machines) by my wife, and preparing to make some new music with these. This is how I usually work with my older machines built in what ever I had on hand for a case at the time, and with new circuit ideas built temporarily on white plastic breadboards. The recordings are made on tape and then transferred to the computer for the final mix down. I do not care for using the computer for sound generating but it makes quick work of multi track production. You should probably also know that I have wanted a modular synthesizer since I was a teenager and over the years I just never seem to have the funds for such a luxury but I did keep building and experimenting with my own circuits. As I recall now in March of 2004 after some 25 years of longing for a Real synth I found myself reading an article about Galileo Galilei and what really caught my attention was reading his thoughts about his life confined in his own home under house arrest and he was getting on in years when he began reading his own book of astronomy at least he began to but had to put it down as he could now not grasp what he himself had penned many years earlier. I thought to myself now in my forties after reading that "This Means Something"! but I had only haplessly placed my bare hand into some cold mashed potatoes left out from the night's meal before. To which I cried "Eureka"! the name of my cat that I had intentionaly poisoned eight times previous and now I was fully aware as should he of the fact that it would not be long now before the cat would meet with his end. It would not be long now that I too as Galileo before me would be too old to make any sense of my own discoveries and writings if I continued to procrastinate. I threw myself into the task of scratch building a full modular analog synthesizer. For the first three months I scoured my personal notebooks of engineering, the internet, and old text books on synthesizers for more circuit ideas and then designed my Persimmon Circuits with a great fervor. My mind had kicked into over drive for what may have been the last time at least in this life time I thought. Partly fueled by large quantities of dark brown coffee with heaps of darker brown sugar, and part by my own determination and desire to accomplish my goal that had only been a vivid dream as a boy out dumpster diving for parts from old radios and TV sets for my early experiments. This was the ultimate experiment and in my laboratory I bread boarded each circuit tested and made corrections improving on what had been done before teaching old circuits new tricks. I purchased a new CAD program for the printed circuit board artwork and created my transfers etching the first few PC boards but then settling in on constructing the bilk of the Persimmon circuits on vector boards with point to point soldering, very tedious. In the beginning after completing the design process I was wiped out and it was a few months before I could even read my own hand written schematics and then the thought was occurring that maybe I was just crazy for three months these drawings look like gibberish I don't really understand what these circuits mean I found myself saying. But I had faith in my work and began stuffing the etched PC Boards and testing them on my work bench and they all worked as expected with only one or two exceptions and those were corrected easily enough. It was during this time that the Star Trek episode called Spock's Brain came to mind and much like Dr. Bones McCoy hurdled with the task of restoring Spock's brain, I too was losing the ability to perform brain surgery but in the end of the episode Mr. Spock was restored to health and at the end of 3 years time I found myself with a brand new fully functional modular synthesizer built by my own two hands, and maybe just a little help from the Teacher of Sigma Draconis VI.

Fred Wilder - June 2007

This page is a chronicle of the Persimmon project with pictures and text.
Persimmon philosophy may be found here.

BREAD BOARD 1
This is a picture of the first circuits for the new synthesizer being built by Fred Wilder.
The picture was taken in March of 2004 and I plan to use this synth on my next CD project.
This synthesizer uses control voltages instead of midi to control and modulate the analog circuits driving the sound. C.V. lends itself to exploration in a way that midi can not begin to imagine. It was Edgar Varese on discussing Control Voltage driven synthesizers; The electronic medium is also adding an unbelievable variety of new timbers to our musical store. But most important of all, it has freed music from the tempered system, which has prevented music from keeping pace with the other arts and with science, Composers are now able, as never before, to satisfy the dictates of that inner ear of the imagination. They are also lucky so far in not being hampered by aesthetic codification-at least not yet! But I am afraid it will not be long before some musical mortician begins embalming electronic music in rules.

- Varese 1962 Lecture at Yale University

The visionary Varese foresaw the coming of MIDI nearly two decades earlier, I wonder if Dave Smith the creator of midi ever thought of himself as a Musical Mortiction? After midi entered the world experimental electronic music died a little. But that's ok its back from the grave now bigger and better than ever like a sonic zombie on crack.

BREAD BOARD 2
June 2004 prototype synthesizer modules are being tested and refined. The schematics generated have now filled a 3 ring note binder and the circuits are coming together nicely. A mahogany 19 rack cabinet was built in April of 2004 to house the music machines. Not pictured here, a 30 step C.V. analog sequencer is being constructed as well.

POWER SUPPLY image 1

POWER SUPPLY image 2
March 2005 The project is coming together nicely now but was side tracked to complete some commissions in 2004. By March of 2005 I have bread boarded and tested all the main modules and settled on a design philosophy to see this project completed soon. All modules are to be of the simplest design using as few components each as possible. The components them selves will be of good quality and lend them selves to good sound, pure analog synthesis. This synthesizer is inspired by the work of Don Buchla, and Serge Tcherepnin and will use banana jacks for patching. I am using a similar color code for these but where Serge used bipolar 12 volts I will use a bipolar 15 volt system. I really dig the Serge layout of his panels and his design philosophy although internally my Persimmon synthesizer is a very different machine I am taking advantage of Serge's idea to make available both audio signals and control voltage signals as controllers through patching and they are both aproximatly the same voltage level in the Persimmon. I built the rack cabinetry after some lengthy contemplation and after visiting a Buddhist temple here in Southern California and have placed painted Buddhas inside my cabinet / temple for music. This is following the tradition of Sequential Circuits that etched many mystical symbols on the circuit boards of their own synthesizers. Here are two photos of the main power supply taken before final assembly. The transformers and parts came from the same Radio Shack that Snoop Dog frequents in Diamond Bar California. So in some fashion the Mentality that is Snoop Dog has some influence on the juice powering this new sound machine.

UPTIME

April 2005 The voltage controlled oscillator I have settled on is a versatile linear response VCO. The design was chosen for it's straight forward simplicity and minimal components count and will be used as the four main VCOs of this modular synthesizer. The VCO features both triangle & square wave outputs and variable frequency & wave form symmetry control. Despite the non-exponential response of the VCOs, hertz/volt as opposed to 1 volt/octave they actually work perfectly for this project, since my intention is the sculpture of new sounds and trekking deep into experimental territory, rather than the recreation of previously developed chromatic compositions. I will be experimenting with Chaos theory, and Fractal geometry to explore Metaproggraming through the creation of electronic music/sound scapes.

RENOVATION

May 2005 Project delayed for studio renovation. I knocked out the wall that held the closet of the Project studio/bedroom and then added a power outlet to the new wall. This will permit me to move the keyboards from off of my test bench where they have been for about two years. I think I can make more head way in the circuit board construction now that I am not working on the kitchen table. This renovation will also make room for the new analog synthesizer cabinet.

FULLERTON HISTORY

May 22 2005 The Production Studio renovation is basically finished and I am back on track. Thought you might like to read a few interesting notes about the town I live in Fullerton, California and its connections to electronic music industry.

Dr. Allen Strange author of Electronic Music Systems, Techniques, and Controls obtained his BA and Masters at CSUF in 1969. Dr. Strange also wrote the operation manual for one of Buchla's machines while attending university here.
Don Buchla's Music box, and Electronic Music System No. 1 and No. 2 were available from CBS Musical Instruments Fullerton, CA, in 1969 early 70s.
CBS was running Fender Guitar after the buy out in 1965, and Leo Fender was working on his MusicMan electric Bass at this time.
To commemorate Leo Fender the inventor of the Electric Guitar and Precision Bass the city of Fullerton knocked down Mr.Fender's original factory and warehouse buildings and erected a parking structure on the site in the 1980s. The parking structure is just North East of the train station and has a nice mural painted on it. Just up the road about two blocks North of the train station is the Fullerton Museum on Pomona Ave. that has a nice exhibit of historic Fender Guitars and amplifiers.

ALTAIR SIX and the BARRONS

January 28, 2006 I attended a special screening of the movie Forbidden Planet at the Gem Theatre in Garden Grove, California. Its a very niece little theatre and it was wonderful to revisit this old friend of a film on a large screen for the first time in my life. I had seen the film many enjoyable times of course on video. Great Sci-Fi, Robby the Robot, Anne Francis, and the Electronic Tonalities by Louis and Bebe Barron. AWESOME! Perfect way to re-spark the creative juices in regards to the Persimmon project. There is a link here for a story on the Barrons and there electronic music. Before Moog and the like had created what we are now familiar with as synthesizers Louise Barron built electronic brains of Op Amps that performed their oscillations and feedback on his test bench and his wife Bebe recorded their sonic offerings to tape and then edited them creating the sound track of Forbidden Planet.

THROAT SINGING

February 2006 It seems like I just started this project but it has been almost two years with all the interruptions and detours time often provides us. Currently I have been building circuit boards again for about 3 weeks solid and today just moved the cabinet from the shop into the studio. I have some photographs of the cleansing ceremony for the new cabinet and the 10 thousand gold Buddhas inside the new sound temple. Strange thing is while I was setting under the Bodhi tree this January and contemplating wether or not I should resume working on this project I heard the churning sound of a hundred Tibetan throat singers. The sound started out as a mere whisper of an idea and then gradually grew louder until there was no mistaking the roar of those big twin engines on the Good Year blimp flying directly over me under the Bodhi tree. Needless to say 2006 is starting out to be very Good Year for Fred, and the Persimmon Synthesizer.

QUAD VCA

March 15, 2006 The very last circuit board of the first two major panels are completed and tested. There are two photos of the Quad VCA Voltage Controlled Amplifier being tested here. Tomorrow I begin drilling out the aluminum panels and get ready to fit up the circuit boards into the cabinet.

Final Assembly

May 29, 2007
Wow, that last entry was over a year ago. Since then I have completed the first two Fast KARL films and successfully taken them to film festivals. I began a third film that was derailed but out of the ashes I have began work on the film project Vampire Flesh and have another film project Bees in the can. I have set aside this next week to devote myself to finally fitting up those circuit boards into the cabinet. It is hard to belive that in just a few more days it will be like Analog Modular Christmas for me. I will use the Persimmon Synthesizer to create the sound tracks for my films this year so everything is coming together as it should. Click on the Tiki to see a photo of Fred wiring up the Persimmon Synthesizer in his Tiki Room project studio.

June 1st, 2007
Success! I finished wiring all the boards this morning and the new synth powered up without a hitch. I have been busy tweeking knobs and inserting patch cables all day. Wonderful Bloobs Bleeps and drones I am so glad I did not give up on my dream. I will post some audio and new photos next week.

Fred

June 6th, 2007
The first two panels of the synthesizer have been tested and installed in the cabinet. Click on the thumb nail image for a larger photo of these sections.
Compliment of top first panel is 4 x VCO each one range ten octaves, 4 x VCA, 4 x Envelope Generators AR, 4 x Intergrators, 4 x Difference engine, 4 x Inverters, 2 x Combo Low pass, High pass, and Notch filters.
Compliment of second panel is 8 x Attenuators, 4 x Three by One mixers.

I have already built several more modules, a ring modulator, and four Voltage controled low pass filters with Q, and have more modules in the works but I am at a point where I can safley leave this now and return to the Vampire Flesh film project. I will definetly be employing the Persimmon Synth in the creation of score for this film.

Here is a link to a short audio file of a simple patch on the Persimmon Synth. AUDIO!

September 27th, 2007
September sees some fruit on the tree. I completed installation of 5 modules, a ring modulator, Dual Voltage controlled low pass filters with Q, Dual Envelope Follower with Schmitt Trigger, and Quad Sample and Hold. These modules were constructed during a 4 week of concentrated building at the test bench. I thought I'd take a break but came down with a cold, oh well I guess I am pushing myself a bit hard again. I am back at construction today and will be working on the LFO Low Frequency Oscillator section now. I am planning to resume filming on Vampire Flesh in October so again I'm cutting it close in regards to time.

The new panels were added in September and can be seen in the bottom of this photograph. The shiny silver panel holds the 5 new modules described above in a PAIA electronics Frac Rack, or Fractional Rack this also contains the main power switch on the far right. These circuits are actually modular in their little aluminum plates. I cut the metal on the radial arm saw and made the holes with a drill press. Lucky to have such a niece collection of bits for this job.
The lower panel the orange one with all the colorful banana plugs and buttons is the mini programer but we have been calling it the Gumbyoscitor 5000 with 6 Pokey power and 2 preamplifiers. This was the last thing I built before succumbing to the weather so you may be able to discern my state of mind by all that color.

Much like yogurt the fruit of my labor is at the bottom.

Fred Wilder