This is a brief timeline of their products.
It's by no means the most extensive list but I hope it can grow over the coming years and be useful
to anyone wanting to discover their drums, pedal, stompboxes and circuits.
Please let me know if there are any mistakes or omissions.
++The company was founded by Mike Matthews in NYC.
++The Axis fuzz pedal (Guild Guitar Company)
++Foxey Lady Pedal (Guild Guitar Company)
++LPB-1 Linear Power Booster.
++Big Muff Pi (First edition on perf board)
++Treble Booster - Screaming Tree ?
++Bass Booster - Mole
++Muff Fuzz (EH2008 and 2009)
++Electro Harmonix “triangle” Big Muff . Version 1
These date from 1969 to 1973. (EH3003)
A rebranded Big Muff V1 made by Electro-Harmonix for Guild.
This transistor version was replaced with an op-amp version in 1975-76.
++EH Freedom Amplifier
++Little Muff Pi (EH-1008)
++Electro Harmonix “ram’s head” Big Muff (Version 2)
(1973-77) EH-3003, the "Face Model"
++ Foxey Lady V5
++Small Stone Phaser - created by David Cockerell of EMS.(1974/75)
++CryingTone Pedal (Wah pedal) '74 chassis.
++Little Big Muff Pi (EH1009) (1975/76)
++ Bad Stone phase shifter. Produced in both two-knob and three-knob configuration.
The three-knob version is more highly sought. Years of Production: 1975 - 1981
++Electro Harmonix Big Muff (transistor and op-amp)
++Electric Mistress (a stereo flanger)
++Deluxe Electric Mistress
++ Memory Man
++Deluxe Memory Man
++ Big Muff Version 3. EH-3003, the "Face Model" in new red/black graphics w/ ON/OFF switch. All units from here on use Version 3 graphics. (1977 to 1978).
++Big Muff Version 4.(1977 to 1978).
EH-3003/EH-1322, the first op-amp version w/ ON/OFF power switch.
++Crying Tone Pedal ('77 Chassis)
++Mike Matthews Dirt Road Special, EH-7050/1313 (AMP)
++ EH-8000 Guitar Synthesizer ‘77-78
++ Hogs Foot Bass Booster
++ Big Muff Version 5. (1978 to 1980)
EH-1322/EH-3003, op-amp version w/ TONE BYPASS switch instead of "OFF ON".
++ Deluxe Big Muff Pi (EH-1330 & EH-3053/3054)
++Slapback Echo (Used ReticonSAD1040)
++Stereo Slapback Echo.
++DRM-16 (DRM = Digital Rhythm Matrix), EH-7450
++Full Double Tracking Effect (used Panasonic MN3005)
++Crying Tone Pedal ('79 chassis)
++DRM-15 (EH-7451) (DRUM)
++ Big Muff Version 6 (1980 to 1983)
EH-3003/EH-3034. Changed back to transistor circuit w/ TONE BYPASS switch.
++RTG - Random Tone Generator
++DRM-32 (EH-7460). (Drum)
++ Crash Pad (drum)
++ Sequencer Drum
++ 2 second Digital delay
Super Space Drum II -'81 (not sure this was ever produced)
16 second Delay
64 second Digital Looping Recorder
EHX declared bankrupt
Matthews launches New Sensor Corp., a new USSR-based company
++Sovtek starts production of EHX pedals in Russia
++Mike Matthews' Red Army Overdrive.
++Sovtek Big Muff Pi (V1) (Green-gold paint)
++Sovtek “Civil War” Big Muff Pi V7 (Blue Gray Paint). A rebranded Red Army
Overdrive. Commonly referred to as the 'Civil War' Big Muff for the
blue and gray US Civil War colours used.
++Sovtek “Green Russian” Big Muff Pi V7.
Tall font version. Identical to the Civil War circuit.
++Sovtek prototype Electric Mistress (only 5 made).
++ Sovtek Green Russian Big Muff Pi V7.
Bubble font version. Slightly different circuit to the tall font version.
++Sovtek “Black Russian” Big Muff Pi V7.
++ Sovtek Black Russian. Big Muff Pi V7
Small box version. Slightly different circuit than the previous edition.
++Electro Harmonix Pi NYC reissue V9. (2000 to present)
EC3003 (2000), EC3003A (2000), EC3003B (2007), EC3003C (2008),
EC3003D (?), EC3003E (2013)
++Mogwai Big Muff Pi V9. "ROCK ACTION"
A special branded stock USA reissue BMP made in a limited run for the band Mogwai.
POG (Polyphonic Octave Generator)
++Little Big Muff Pi V10 "XO". Three knob nano sized Big Muff.
2006 to present. PCB Numbers: EC-D1, EC-D2, EC-D2 Revs A - E, EC-D3
++Big Muff Pi USA reissue V9 .Circuit revision C.
The BBM was based on the green Russian Big Muffs and the original 1970s Big Muffs.
Circuit board is populated with SMD components.
Transistors are BC547C which were used in the last black Russian Big Muffs.
2009 to present.
++Germanium 4 Big Muff Pi V13. This is a fuzz pedal and overdrive combo.
++ Nano Big Muff Pi. Version 10A .
++ Deluxe Big Muff Pi. Version 10B.
Dating EHX Pedals etc
The vintage EH pedals, all have codes stamped on the underside of the potentiometer.
EHX often used CTS (Chicago Telephone Supply) brand cans, or “pots”.
The first three numbers are a code identifying the manufacturer : CTS.
The next two numbers are the year
The last two numbers are the week of the year they were made.
So a pot stamped 1377615 was made in the 15th week of 1976. Note that this does not mean a pedal with a 1976 pot was actually made in 1976, it just means it was not made any earlier than 1976.
The pedal could have been made months or years or more after the pots were made.
Russian pedals & pots on USA made pedals from around 1999 do not have date codes.
Reverb - a brief history of EHX pedals
Pro Guitar shop
EH Man's Extravaganza