I've always been interested in electronics and music.  I played in a band in the '60's with a Farfisa organ and a Vox Essex Bass amp (I still have both).  My introduction to electronic synthesizers was an ARP 2600 at Evergreen State College and later on an ARP Odyssey.  My first synthesizer was an Ensoniq EPS-16+ but I longed for analog.  I starting with a PAiA Fatman and then progressed to a Matrix-1000, Sequential Circuits Six-Trak, Arp Odyssey, Arp Avatar / Sequencer, and finally began to build my modular in 2001.  My electronics experience started in middle school and by high school I had a part time repair business which helped fund my electronics college education.  Here is a photo of my high school repair bench.

The Synth

This synthesizer has now grown to over 100 modules and I never imagined it would have gotten this large.  Originally I wanted to keep my synthesizer all analog but a small portion of my modules are now digital.  I have a few out-board digital effects units but I still prefer my reel-reel tape for echoes and delays.  Hopefully you'll find some useful information here. I've documented my modular designs, many of my module modifications, and my synthesizer projects with reference information and photos.

This Site

I make nearly everything I do public domain.  I've learned from others and this site is help others learn from what I have done.  I'm delighted by the number of emails and feedback I receive from people using this site.  Send me an email if you have a question.


My Help

I've done electronics repair and restoration for decades.  I used to operate my own electronics repair business and I restore vintage radios as a hobby.  I repair a lot of tube radio, audio, and music equipment and I've done microprocessor and digital system design for Tektronix so I enjoy working on vintage synthesizer restoration.  Most of my synthesizer, organ, and amplifier collection were purchased broken for parts but I usually then end up restoring them - I just hate to part out vintage equipment.  I have the time and interest to be able to help and assist fellow Synth-DIY'ers with their projects and formed Modular Synthesis, LLC to help. I've even helped successfully diagnose and repair modules by email.  Contact me if I can be of help or assistance with your project, design, repair, or restoration.


Contact me if I can be of help or assistance with your project, repair, design, or restoration.

Repairs, custom projects and customer testimonials

Items that I have currently for sale

I spent 34 years at Tektronix working with some of the best people in all parts of the company: Computer Graphics, Video & Networking, and Test & Measurement.  I've since retired to enjoy my hobbies and now have time to devote to my music and electronic projects as well as volunteer at the vintageTEK museum.

My professional information on LinkedIn

My Tektronix memorabilia

My 1949 Chevrolets - my other hobby

My designs are indicated with a superscript¹

Modifications of existing designs are indicated with a superscript²

Quick Links

Latest Projects

Synthesizer Restoration and Builds
VCO Scaler1  New Aries modules
4U 200 Series Format Joysticks1 Buchla and 100/200 Series 4U modules  Photos
4U 200 Series Format Oakely midiDAC2 M.E.M.S. Project 100/200 Series 4U modules
4U 200 Series Format Slant Cabinet1 Fonitronik mh21 Triple Resonator
AMF 775-A Educational (Analog) Computer Loft 450 Delay Line/Flanger
4U 248 MARF V2 HW & SW Mods2 Milton Sequencer
Blomman BLM 277 Signal Delay Unit Moog Micromoog
DJB-005 Voltage Monitor¹ Moog Modular  Photos
Behringer Model D rack mount² Moog Modular Reissue
Thomas Maximus VCO Moog Sonic Six synthesizer
Thomas Henry SN-Voice Moog Source
4U 200 Series Format 24 dB VCF and Clock² Oberheim Mini-Sequencer (MU repackage)
5U Chaotica Oberheim SEM
5U Benjolin² PAiA 2720 Synthesizer
Jürgen Haible "solina" triple chorus PAiA 4700 Synthesizer Modules
Ian Fritz DoubleDeka VCO² Papareil Labs Quantix-8²
5U E950 Circuit Bent VCO Roland System 100 - 140 module
CGS-35 Steiner VCF² SCI Model 700 Programmer
Thomas Henry mega percussive synthesizer SCI Model 800 Sequencers
5U E560 deflector shield Serge
Barton dual quantizer² Synton 3000 series modules
DJB-021 pan-crossfade² WASP synthesizer
5U 266 source of uncertainty² YUSynth Dotcom Mini-Moog VCF
Polivoks VCF²
5U E580 sampling mini-delay Photos, Videos, and Sound Samples
Ian Fritz 'threeler' 3rd order VCF² Photo album
DJB-020 tap tempo LFO¹ Video and Sound samples
5U 208 pulser-crossfader-timbre generator² Hammond M-3 tonewheel generator
My visit with the Raymond Scott Electronium
5U Modular Synthesizer Information   
Module listing by cabinet Organs and more
Custom modules design files and photos¹ Hammond B-3 and Leslie 142
Purchased modules and modifications² Hammond M-3 tonewheel generator  Photos
Dotcom modules Hammond vibrato scanner module²
Main cabinets & power distribution¹ Hammond zinc whiskers Photos
Side cabinets & power distribution¹ Organs, keyboards and amplifiers
Tektronix 760A Stereo Audio Monitor   
Electronics Projects and Repairs
Reference Information AMF 775-A Educational (Analog) Computer
Modular synth tips Bell Sound Systems RT-205 & BT-205IB
Parts and DIY information Electronic project information
Making PCB brackets Electronic repairs and tips information
Module Conversions Fender Tremolux Restoration
440 Hz sine wave reference oscillator¹ Sony TA-E88 Restoration
Power supply sequencing¹ Synthesizer XY laser²
PT2395 delay module²
Vactrol measurements 5U ComputerVoltageSource Module
CVS eight channel module¹
Related Musical Projects CVS 2x16 LCD display¹
Circle machine sequencer¹ CVS four channel module (PSIM software compatible)¹
MIDI 88 note keyboard² CVS Kurzweil ribbon controller¹
MIDI bass pedals¹ Synthmodules.com PSIM and SpeakJet²
MIDI processor¹ CVS and PSIM I/O expansion module¹
SpeakJet  speech synthesizer² CVS and PSIM Programs¹
Yamaha Tenori-On Arduino-based ComputerVoltageSource¹

Synthesizer Projects

5U Modular Synthesizer

My modular synthesizer now consists of 127 modules including Analog Metropolis, Barton Musical Circuits, Blacet, Bridechamber, Catgirl Synth, ElectricMusicStore, Encore, Flight Of Harmony, Ian Fritz, Jürgen Haible, Rob Hordijk, Larry Hendry, Magic Smoke Electronics, Moon Modular, MOTM, Natural Rhythm Music, Neil Johnson, Oakley Sound Systems, Synthcube, Synthesizers.com,  Synthmodules.com, YUSynth, and about two dozen of my own designs.


5U synthesizer modules and external equipment index

5U Side synthesizer modules index

Design files and photos for my custom modules¹

Information, mods, and photos for purchased modules²

Parts and construction information

MP3 samples of some of my favorite patches



Here is a painting of my modular synthesizer that my son gave me.


5U Modular CV Keyboard

I rebuilt an ARP-3604 keyboard with a wood cabinet and updated electronics.

Information & photos for my ARP CV keyboard²



5U Modular Cabinets and Power Distribution

I built a 19" rack cabinet (30 modules and 2U standard rack) and a four stack of wood cabinet (96U).  I later replaced the 19" rack cabinet with a four stack wood side cabinet (36U+10MU).

Info & photos of my initial 19 inch 5U rack cabinet¹


Info & photos for 5U wood cabinets & power distribution¹


Info & photos for 5U side cabinets & power distribution¹


Info & photos for 5U power-on delay¹

Info & photos for 5U rear AC mains module¹



4U 200 Series Format Modular Synthesizer


I built a small cabinet for my initial 200 series modules. Much like my 5U system, it grew significantly so I built this 36U slant cabinet

Various 4U and 8U 200 Series cabinets¹


36U 200 Series slant cabinet¹



5U ComputerVoltageSource Module


I designed the ComputerVoltageSource module using an AtomPro28.  Features include:
     8 analog inputs (0 to 10 volt with 0 to -5 volt offset at 10 bit resolution)
     8 analog outputs (0 to 10 volt at 12 bit resolution)
     3 digital inputs
     MIDI in / out
     I2C expansion (for additional inputs and outputs)
     2x16 LCD display.

Info and photos for the ComputerVoltageSource module¹


Info and photos for the ComputerVoltageSource display¹

Information and photos for a four channel version¹

Information and photos for a dedicated ribbon controller¹

Arduino-based ComputerVoltageSource¹



Synth Display Modules

I built an external display using a 2x20 LCD module with MIDI or serial input and three display modes.

Information and photos for my external display module¹


I built two dedicated displays for my programmable PSIM (2x8 LCD) and ComputerVoltageSource (2x16 LCD) modules.

Information and photos for my PSIM 2x8 display¹


Info and photos for the ComputerVoltageSource display¹



MIDI Bass Pedals

I built a set of MIDI bass pedals using Hammond organ pedals and an AtomPro24 controller.  Features include:
       Normal, Mono, and 'Sticky" modes (sticky=note held until next note played)
       Normal, One-Shot, and 'Sticky" arpeggiator modes
       5 built-in arpeggiator sequences and a user-recordable 100 note sequence
       Normal, -1 and +1 octave select
       MIDI in merge
       Internal or MIDI clock
       External LCD note display

Information and photos for my MIDI bass pedals¹



88 Key MIDI Keyboard

I built an 88 key MIDI keyboard from a salvaged Kurzweil Ensemble Grand Mark III digital piano.  I used the original keyboard controller and built a custom wood cabinet.

Information and photos for my 88 note keyboard²



MIDI Processor

I built a MIDI processor which is self-powered and provides multiple transformations.  Features include:
     Key transpose
     Channel transpose
     Keyboard split
     Keyboard reverse
     Specific continuous controller transforms

Information and photos for my MIDI processor¹



A440 Reference Oscillator

I designed a 440 Hz sine wave reference oscillator using only two 8 pin DIP components.

Information and photos for my A440 oscillator¹



Hammond Vibrato Scanner Module

I built an external electro-mechanical vibrato and chorus using a Hammond Organ scanner and delay line.  A small DC motor and speed controller varies the vibrato frequency.

Information and photos for my Hammond vibrato scanner



AVR Synth

I built the AVR Synth PCB to have a small format synthesizer but never completed this project.

Information and photos for my AVR Synth



Synth Controlled Laser Light Module

My first laser was a modified Ramsey Electronics laser light (LLS1) with CV control of the motor speed.  I built an AVR plug-in that replaces the 555 timers to interface to my synth 5 volt CV levels.  Later I built a full X-Y laser for synthesizer CV control.

Ramsey LLS1 modification document²


Synthesizer Laser²



PAiA Fatman Mods

My son has a PAiA Fatman and we enhanced it with a number of modifications.  Some of the modifications were from various sites on the internet and some I designed.  I consolidated all the modifications into a single document.  Modifications include hard sync, lower frequency range, separate VCO attenuators, sub-octave generators and attenuators, ring modulator and attenuator, LFO filter modulator, and separate VCO tuner output.

PAiA Fatman modification documentation²



Organs, Keyboards, and Amplifiers

 I have information and photos of my various keyboards, amplifiers, Hammond organs, and Leslie speakers.

Info and photos for my organs, keyboards and amplifiers


Keyboard and organ studio layout



Electronic Projects and Restorations

This is my  non-synthesizer electronic projects page.   I have information and photos of two 70's stereos, projects such as an FM transmitter and scrolling display, and various repair and restoration information for amplifiers, speakers, and turntables.

Info and photos for my electronic projects


Info and photos for my electronic restorations and repairs