Saturday, 21 October 2017

EHX Big Muff - Basic build

This must one of the most studied, rebuilt, cloned, copied circuits ever.
The famous Mike Matthews Electro-Harmonix Big Muff guitar pedal. Pink Floyd used it. So did the Smashing Pumpkins. Jimmy Hedndrix gave it immortality. The list of artists is endless.

There are countless variations too. You can buy kits on the net with PCB & parts supplied to save you the hassle of understanding the circuit. But I like to know how things work. I'll build this on perf board.
So here is the basic circuit. Many thanks to Kit Rae for a wonderful website.
If you haven't visited it yet here is the link:
This is the site to go to for everything you could ever need on this topic.

The first pedals came out in the late 1960s and over the last nearly 60 years the designs have barely changed. It says a lot about how good the basic design is. Of course there has been lots of tweaking over the decades. At one point the four transistor design was changed to op amps. And for another one of those decades Electro-harmonics transferred production to Russia.

Today the company is strong and still building Big Muffs. I highly recommend the modern versions (I own a few and love them) but I think it is fun and educational to explore the older variations. These go for astronomical prices on Ebay & Reverb today. Vintage "Triangle" and "Foxey Lady" pedals regularly change hands for over $1500.
If you can afford the real vintage thing go for it as I think nothing really beats vintage components. They have a persona which only the years can give. But probably the only chance I will have to experience something like the vintage sound will be to build my own.  So below is a brief comparison between the different variations. It's a great way to explore the evolution.

Starting with the early "Triangle" pedal

Triangle V1

Circa 1971 Circa 1971/2 Circa 1972-73

R2 33k 33k 33k
R3 100K 100K 100k
R4 2.7K 2.7K 2.7k
R5 33k 33k 39k
R6 10K 12K 12k
R7 390K 390K 390k
R8 33k 33k 39k
R9 470k 470k 390k
R10 150R 100R 82R
R11 15K 15K (or 12K) 22k
R12 8.2k 8.2k 8.2k
R13 15K 10K (or 15K) 22k
R14 100K 100K 82k
R15 470k 470k 390k
R16 100K 100K 82k
R17 470k 470k 390k
R18 10K 10K 12k
R19 8.2k 8.2k 8.2k
R20 100K 100K 82k
R21 100R 100R 150R
R22 100R 100R 82R
R23 1K 820R 820R
R24 100K 100K 100k
R25 100K 100K 100k
R26 100K 100K 100k

C1 0.12uF 0.1uF 0.1uF
C2 1uF (or .1uF) 0.1uF 0.1uF
C3 1uF 0.1uF 0.1uF
C4 1uF 0.1uF 0.1uF
C5 0.12uF 0.1uF 0.1uF
C6 0.12uF 0.1uF 0.05uF
C7 1uF 0.1uF 0.05uF
C8 0.01uF 0.01uF 0.01uF
C9 0.004uF 0.004uF 0.004uF
C10 500pF 500pF 500pF
C11 500pF 500pF 560pF
C12 500pF 500pF 560pF
C13 0.12uF 0.1uF 0.1uF

Q1 2N5133 FS36999 FS37000
Q2 2N5133 FS36999 FS37000
Q3 2N5133 FS36999 FS37000
Q4 2N5133 FS36999 FS37000

D1 1N914 1N914 1N914
D2 1N914 1N914 1N914
D3 1N914 1N914 1N914
D4 1N914 1N914 1N914

The values seem to have changed slightly over those 3 years.
There is a lot of scope to do some tweaking to find that sound that's right for your needs.
Maybe play around with carbon vs metal resistors? In the 1970s those carbon resistors would have been 10% tolerance or more ???

R24, 25 & R26 are the pots.  
Vintage USA Big Muffs (V1, V2, V3) used single-gang, linear taper, 24mm,100k potentiomers.
A possible future mod could be to use B100K for R25 & R24 & A100k for the Tone (R25).
Log pots (A-100K type) have a longer usuable mid position and less at the ends. ... better fine tuning.
Could be useful for the tone section.

 Leakage current for the 1N4148 as 5 µA .... I think the same as the old 1N914

What transistors to use???
They need to be NPN bipolar
BC549C, BC550, BC239, SE4010, and 2N5210 work according to Kit Rae.
2N5088, 2N5089, MPSA18, 2N3904, 2N4401 are possible candidates.
It might be best to use sockets to allow experimentation.
Were the transistors matched in the early pedals?

Kit Rae's valuable diagnosis identifies three sets of components which alter the BMPs the most.
1. The clipping blocking caps. (C6, C7)
2. The feedback / filter caps. (C10, C12, C11)
3. The Tone stack filter. (C9, C8, R8, R5).

The clipping blocking caps
" C6 & C7 determine the bandwith to be clipped by the diodes". They are usually identical in value and have a great effect on the sound. The smaller the value, the more bass. From the photos I've seem it looks like these are ceramic.

Feedback Filter caps;
C10,C12,C11 usually have identical values. They determine how buzzy/fuzzy the pedal sounds. "They filter the amount of high frequencies. Larger values roll off more highs and smaller values give more crunch and buzz to the sound. The better sounding vintage Big Muffs tend to have the larger values and sound smoother and warmer. Modern Big Muffs tend to have the lower values and sound a bit more buzzy/fuzzy." (Kit Rae).

The pics of vintage units indicate ceramics.

The ToneStack filter.
These 4 components surround the tone pot (R25).
C8, C9, R8 & R5. This section influence the mid frequencies. The more mids that are removed, the deeper & darker will be the sounds and the more the muff will probably stand out in a mix. The two resistors determine the amt of mids removed. Looks like 33K was the most common value for R8 & R5.
"Higher values have less mids scooped out and lower values have more mids scooped. This resistor also works in conjunction with the high pass tone capacitor (.0004uF in the example above) to affect the treble at low tone settings. Reducing this cap to .003uF alters the range and scoops slightly more mids. Increasing to .004uF reduces the scoop. Combined, a larger high pass cap and smaller resistor decreases the treble at low tone settings." (Kit Rae)

The pics of vintage V1 boards suggest C8 is a polyester  & C9 be ceramic.

Muffs Guts (Kit Rae)
Electro-Harmonic's Time Line

To be continued......

Electrofringe 17

Cant wait for this.
Electro Fringe 2017

I'll be helping Andrew (Virusinstaller) perform a set at EF17 .

A post shared by jono (@dj_jondent) on
Electrofringe's #EF17 is creating a cosmic rip in 107 Projects to liberate artists, hackers and musicians into Sydney's expanding space of electronic art. From scattering rays to altering consciousness, EF17 sets an open platform for experimental ideas, practices and techniques. Interact with bioelectrical machines, dance to a raw music program, and learn how to mousejack your housemate's computers all for FREE over one day

This is a sample

A post shared by jono (@dj_jondent) on

Saturday, November 4 at 1 PM - 11:45 PM
107 Redfern St, Redfern. Sydney

Thursday, 19 October 2017

EHX -Little Big Muff Pi - "The Op Amp Muff "

Some pics of this beautiful vintage pedal.
It's a Electro-Harmonix Little Big Muff with the rare Op-amp circuit.
Up until 1978, the traditional Big Muff circuit used four transistors.
But in an effort  to reduce costs operational amplifiers were substituted. These versions can be found
in the V4 & V5 PCBs. Model Numbers: EH3003A, EH3003B, EH1322, EH1322B, EH3003.
Some of the same circuit boards used in the Big Muff V4 were also used in the Little Big Muff
The Big Muff has 3 knobs: Volume, Tone & Sustain. The Little Big Muff only has a Volume knob.

The Op-amp versions are often describes as "grungier" than the traditional transistor designs.

The PCB is labelled EH-1322.
Thus its a version 4 or V5.
Its the Op-amp version.

The RC4558 is a Dual General Purpose Op-ap.

The UA741 is also a general purpose Operational Amplifer.

The Pot ID: 1377840.
Thus the date : The 40th week of 1978
 The Muff guru Kit Rae describes the Op Amp Muff thus:
"I am including this as a legitimate Big Muff, even though it was not built on the classic Muff four-stage circuit. It was intended to sound like a Big Muff and was released in the same box as Version 3, so I feel it must be included as a true Muff version. Plus, I, and many others like them. It has a huge, crushing Big Muff sound. Though not quite the same as the organic transistor tone, is was very unique. Supposedly only a few thousand of this version were made".

"Version 4 is likely the Big Muff circuit heard on most of Smashing Pumpkins' Siamese Dream and Pisces Iscariot albums, so that should give an idea of the potential of this version. This is the rarest of the two op-amp Big Muff versions".(

Electro-Harmonix Time Line
KitRae - The BigMuff OP Amp version

Doepfer Module A-188-1

Still on the search for the perfect Bucket Brigade Device module.
I just purchased these two on Ebay.
The A-188  series of Doepfer Eurorack modules are great value. They use the Panasonic BBD chips and as always with Doepfer, the build quality is excellent.

The A-188-1 X uses a MN3009. Its a 256 stage IC. These are getting hard to find.

The A-188-1 Y uses a 512stage BBD.

This module happens to be using a newer Panasonic MN3204 IC. These 32xx ICs are lower voltage than their 30xx cousins.

You can read the manual here:

Singapore - Marina Bay Sands

I don't normally write about hotels but this one is pretty special.
Even if you don't stay here, the view from the observation deck is jaw dropping.
 Best to get there a hour or so before sunset and just watch the skyline change.
The 3 main buildings are united on the top with a platform which comprises the observation deck of the left .. open to the public and the closed section with infinity pool on the right.

 I was quite amazed with the architecture of Singapore. But more of that in a later post.

Wednesday, 18 October 2017

Studio for electronic music -Google Doodle

It's 66 years since the foundation of "The Studio for Electronic Music".
Google celebrated this milestone with a Google Doodle.
 The doodle is created by Berlin-based illustrator Henning Wagenbreth.

The studio was established in the old WDR (Westdeutscher Rundfunk) building in Cologne on the 18th Oct, 1951. The WDR was a West German Broardcaster. Though closed in 2000, it is now regarded as the first modern Electronic Music Studio.

To put this in context, the BBC Radiophonic Workshop was founded in 1958 and the San Francisco Tape Music Center was founded in 1962. The score for the film Forbidden Planet, by Louis and Bebe Barron was composed in 1956. They used custom built electronic circuits and tape recorders.

 By © Raimond Spekking / CC BY-SA 3.0 (via Wikimedia Commons), CC BY-SA 3.0,

In these early post war days the only organisations that could afford complicated and expensive electronic equipment were national broardcasters like the BBC and WDR or universities like Colombia in the USA. These were often set up for nationistic reasons or to help in production of TV shows like Dr Who (in the case of the BBC). Before the advent of smaller & cheaper modular synthesizers, electronic musicians were heavily reliant on these institutions.

The composers Werner Meyer-Eppler, Robert Beyer, and Herbert Eimert were instrumental the foundation of the Westdeutscher Rundfunk (WDR) studio. The studio welcomed musicians from all over the world including including Ernst Krenek (Austria/USA), Cornelius Cardew (England) and Nam June Paik (Korea). Karlheinz Stockhausen was one of the studios most famous artistic directors.
.Karlheinz Stockhausen in the Studio for Electronic Music in 1991

The studio was set up around the idea of producing "electronically synthesised sound".
This was in sharp contrast to the "musique concrète" acoustic approach at "Groupe de Recheches Musicales" in Paris.

Heath Ag-10 Sine & Square wave generator.

Bruel & Kjaer - Beat Frequency Oscillator

Eimert was officially succeeded as director of the studio by Karlheinz Stockhausen in 1963.

Other instruments used in the studio included some from the following manufacturers:
ARP, Buchla, EMS, Hamond (organ?), Korg, Moog, Oberheim, Roland, Sequential Circuits and Yamaha.
I have read they they had a Ondes Martenot, an early Thermin, a Trautonium and a Telharmonium, but i can't confirm this. If you have any info regarding this please let me know.


Monday, 16 October 2017

Electro-Harmonix Time line.

I have started building a collection of EHX pedals. It's a great company with an illustrious history.
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)
    My build of one of these on perfboard is here .
++ Foxey Lady V4. Three knob version. 
     A rebranded Big Muff V1 made by Electro-Harmonix for Guild.

++ Little Muff Pi (EH-1008).
     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.
++ Knockout Attack EQ, model # EH-3004 

++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
++Rhythm-12 Drum Machine 
++Attack Equalizer ( 3-band rotary EQ)
++Little Muff Pi Op-amp version of 1971 Little Muff Pi.
++Little Big Muff Pi (EH-1009, EHSP1). One knob version of the Big Muff V3 

++ 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)
++ Deluxe Electric Mistress EH1318A
++Slapback Echo (Used ReticonSAD1040) EH1315
++Stereo Slapback Echo.
++DRM-16 (DRM = Digital Rhythm Matrix), EH-7450
++Domino Theory  
++Little Big Muff Pi (EH-1322 V4/5 circuit). Op Amp version.
LBM EH-1322
++Full Double Tracking Effect (used Panasonic MN3005) 
++Crying Tone Pedal ('79 chassis)
++DRM-15  (EH-7451) (DRUM)
++3-Phase Liner  
++ Space Drum - ‘79 
++ Little Big Muff . EH3034 transistor version  
++ Muff Fuzz. Op-amp version 
++ Deluxe Electric Mistress Version 2 ...EH 5150

++ Big Muff Version 6 (1980 to 1983)
     EH-3003/EH-3034. Changed back to transistor circuit w/ TONE BYPASS switch.
++ Deluxe Big Muff Pi (EH-3053 and 3054A, B, and C)
++RTG - Random Tone Generator
++DRM-32 (EH-7460). (Drum)
++ Crash Pad (drum)
++ Sequencer Drum
++ Clockworks
++ 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.
    Identical circuit to the green Russian. 

 ++ 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.
++Double Muff. Two 1969 Muff Fuzz circuits in one box. Discontinued in 2008.
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 B.
++Stereo Memory Man with Hazarai’s

++Big Muff Pi USA reissue V9 .Circuit revision C.
++Bass Big Muff V11. This replaced the Russian made Big Muffs.
    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. 
++Nano Muff Overdrive. Reissue of the 1969 Muff Fuzz/Little Muff Pi.  
++Tone Wicker Big Muff Pi V12
     2009 to present.
++POG 2

++Germanium 4 Big Muff Pi V13. This is a fuzz pedal and overdrive combo.
++Nano Double Muff.

++Deluxe Bass Big Muff. Version 11A

++ Nano Bass Big Muff Pi, Version 11B.
++ 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