Big Muff BlenderAll your bass fuzzare belong to us

Contents of this document are ©2016 Pedal Parts Ltd.No reproduction permitted without the express writtenpermission of Pedal Parts Ltd. All rights reserved.

Schematic + BOM

R6 1MR20 1MR27 100KR28 3K3R29 100K

C15 1uC16 10u elec

Q5 N-Channel FET(J201, 2N5457)

BLEND 100KA

The main schematic shows the basic Big Muff Pi used throughout most of its history with twosmall additions:

• Diode lift switch for Q2 clipping

• Shift pot added to the Tone section

These are both optional - see later in the document.

Not sure what to make? Check out Kit Rae’s bigmuffpage.com - this guy knowsmore about all things Muff than Mike Matthews himself. Astounding work.

The schematic highlighted in green is the blend circuit. Here’s the BOM for that:

With the BLEND pot fully CCW you should have aclean signal pretty much the same as yourbypassed level.

Carefully tweak the VOL and BLEND controls to getyour desired balance of clean and fuzz. The two arevery interactive.

Important notesSHIFT/MIDSIf you are NOT using this control you must place a jumper wire between pads 1 and 2.

DIODE SWITCHIf you are NOT using this switch but want to keep the clipping diodes in the circuit, you mustplace a jumper between the pads as shown below. If you want no clipping here, just leave it out.

C14The PCB has been designed so C14 can lay flat to save on height - see cover image. Though thevalue of this cap has changed throughout the life of the BMP, 100u is supplied with all kits.

Tone SectionThe PCB has been designed with an extra pot to control the MIDS of the circuit. You have severaloptions here. The values listed below replace the same part numbers shown on the BOM foreach Big Muff variation shown later in this document. If using any of the tone variation shownbelow, USE THESE VALUES, not those shown on the standard Muff BOMs.

STANDARD TONE WITH SHIFT POTNot the best implementation, but it will give you some control over the mids.

R18 10KSHIFT 25KB

AMZ PRESENCE V1Much more control over the mids. A very nice mod without straying too far from the BMP.

R18 3K3C10 10n (actually 12n in the AMZ guide, but 10n is easier to source and gives good results)C11 10nSHIFT 25KB

AMZ PRESENCE V2A huge range of tonal variation, with humped as well as scooped mids available.

R18 3K3R19 470KC10 15nC11 1n5SHIFT 25KBTONE 250KA

For more info on the above go to:http://www.muzique.com/lab/tone3.htm

The power and signal pads on the PCBconform to the FuzzDog Direct Connectionformat, so can be paired with the appropriatedaughterboard for quick and easy offboardwiring. Check the separate daughterboarddocument for details.

Be very careful when soldering the diodes andtransistors. They’re very sensitive to heat. Youshould use some kind of heat sink (crocodileclip or reverse action tweezers) on each leg asyou solder them. Keep exposure to heat to aminimum (under 2 seconds).

Snap the small metal tag off the pots so theycan be mounted flush in the box.

Positive (anode) legs of the electrolytic capsgo to the square pads.

Negative (cathode) legs of the diodes go to thesquare pads.

You should solder all other board-mountedcomponents before you solder the pots. Oncethey’re in place you’ll have no access to muchof the board. Make sure your pots all line upnicely. The best way to do that is to solder asingle pin of each pot in place then melt andadjust if necessary before soldering in theother two pins. If your pots don’t haveprotective plastic jackets ensure you leave adecent gap between the pot body and the PCBotherwise you risk shorting out the circuit.

Same goes for the toggle switch. Use yourenclosure as a guide for positioning them toensure they line up properly. Solder one lug,then melt it and adjust to get it straight beforesoldering any others.

PCB la

yout ©

2016

Ped

al Parts Ltd.

C1 100nC2 470pC3 1uC4 1uC5 470pC6 100nC7 1uC8 470pC9 100nC10 3n9C11 10nC12 100nC13 100nC14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 100KR3 470KR4 100RR5 15KR7 1KR8 8K2R9 100KR10 470KR11 15KR12 100RR13 8K2R14 100RR15 470KR16 100KR17 15KR18 100KR19 39KR21 100KR22 390KR23 2K2R24 10KR25 1M

3rd (70s)

C1 100nC2 470pC3 100nC4 100nC5 470pC6 47nC7 100nC8 470pC9 47nC10 3n9C11 10nC12 100nC13 100nC14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 100KR3 470KR4 390RR5 12KR7 1KR8 10KR9 100KR10 470KR11 12KR12 390RR13 10KR14 390RR15 470KR16 100KR17 12KR18 22KR19 20KR21 100KR22 470KR23 2KR24 10KR25 1M

GreenRussian

C1 100nC2 470pC3 100nC4 100nC5 470pC6 47nC7 100nC8 470pC9 47nC10 3n9C11 10nC12 100nC13 100nC14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 100KR3 470KR4 390RR5 12KR7 1KR8 10KR9 100KR10 470KR11 12KR12 390RR13 10KR14 390RR15 470KR16 100KR17 12KR18 22KR19 22KR21 100KR22 470KR23 2K7R24 10KR25 1M

BlackRussian

C1 100nC2 560pC3 100nC4 100nC5 560pC6 47nC7 100nC8 560pC9 47nC10 3n9C11 10nC12 100nC13 100nC14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 100KR3 470KR4 390RR5 12KR7 1KR8 10KR9 100KR10 470KR11 12KR12 390RR13 10KR14 390RR15 470KR16 100KR17 12KR18 22KR19 20KR21 100KR22 470KR23 2K7R24 10KR25 1M

Civil War

C1 100nC2 560pC3 100nC4 100nC5 560pC6 47nC7 100nC8 560pC9 47nC10 3n9C11 10nC12 100nC13 100nC14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 3K3R2 82KR3 390KR4 820RR5 22KR7 1KR8 8K2R9 82KR10 390KR11 12KR12 150RR13 8K2R14 820RR15 390KR16 82KR17 22KR18 39KR19 39KR21 100KR22 390KR23 2K7R24 12KR25 1M

Triangle

C1 10u*C2 560pC3 100nC4 100nC5 560pC6 100nC7 100nC8 560pC9 1u*C10 3n9C11 10nC12 100nC13 1u*C14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 47KR3 470KR4 120RR5 10KR7 1KR8 10KR9 100KR10 470KR11 10KR12 150RR13 10KR14 150RR15 470KR16 100KR17 15KR18 22KR19 39KR21 100KR22 430KR23 3K3R24 15KR25 1M

Ram’s Head*Originally electrolytic but you’ll get much better results replacingthese with 1u film caps.

C1 100nC2 470pC3 100nC4 100nC5 4700pC6 100nC7 100nC8 470pC9 100nC10 3n9C11 10nC12 100nC13 100nC14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 33KR2 100KR3 470KR4 100RR5 12KR7 560RR8 8K2R9 100KR10 470KR11 12KR12 100RR13 8K2R14 100RR15 470KR16 100KR17 12KR18 33KR19 33KR21 100KR22 470KR23 2K7R24 12KR25 1M

VioletRam’s Head

C1 1uC2 470pC3 1uC4 1uC5 470pC6 1uC7 1uC8 470pC9 1uC10 3n9C11 10nC12 1uC13 1uC14 100u

Q1 2N5088Q2 2N5088Q3 2N5088Q4 2N5088

D1 1N4148 / 1N914D2 1N4148 / 1N914D4 1N4148 / 1N914D5 1N4148 / 1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 100KR3 510KR4 100RR5 10KR7 1K8R8 10KR9 100KR10 470KR11 10KR12 390RR13 10KR14 390RR15 470KR16 100KR17 10KR18 22KR19 22KR21 100KR22 470KR23 2KR24 10KR25 1M

NYC Reissue

C1 1uC2 470pC3 1uC4 1uC5 470pC6 1uC7 100nC8 470pC9 1uC10 3n9C11 10nC12 100nC13 1uC14 100u

Q1 MPSA18Q2 MPSA18Q3 MPSA18Q4 MPSA18

D1 1N4148/1N914D2 1N4148/1N914D4 1N4148/1N914D5 1N4148/1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 100KR3 470KR4 100RR5 15KR7 1KR8 8K2R9 100KR10 470KR11 15KR12 100RR13 8K2R14 100RR15 470KR16 100KR17 15KR18 22KR19 39KR21 100KR22 390KR23 2K2R24 10KR25 1M

V3 79#2- J MascisBased on what is supposedly one of J Mascis’ favourite Muffs.The original has true tone bypass, this doesn’t. Deal with it.

C1 100nC2 500pC3 100nC4 100nC5 500pC6 47nC7 100nC8 500pC9 47nC10 3n9C11 10nC12 100nC13 100nC14 100u

Q1 2N5089Q2 2N5089Q3 2N5089Q4 2N5089

D1 1N4148/1N914D2 1N4148/1N914D4 1N4148/1N914D5 1N4148/1N914

SUSTAIN 100kATONE 100kBVOLUME 100kA

R1 39KR2 100KR3 470KR4 390RR5 12KR7 1KR8 10KR9 100KR10 470KR11 12KR12 390RR13 10KR14 390RR15 470KR16 100KR17 12KR18 22KR19 20KR21 100KR22 470KR23 2K7R24 10KR25 1M

Tall FontGreen RussianBass players’ favourite. The feedback caps in the originalare two 1nf in series, but that’s the same as 500pf.

C1 100nC2 560pC3 100nC4 100nC5 560pC6 1uC7 100nC8 560pC9 1uC10 4n7C11 10nC12 100nC13 100nC14 100u

Q1-4 BC549C*

D1-2 1N4148D4-5 1N4148

SUSTAIN 100KATONE 100KBVOLUME 100KA

R1 33KR2 100KR3 470KR4 470RR5 10KR7 1KR8 10KR9 100KR10 470KR11 10KR12 150RR13 10KR14 150RR15 470KR16 100KR17 10KR18 33KR19 33KR21 100KR22 470KR23 2K7R24 10KR25 1M

Stoned ClericStoner heaven, based closely around a Ram’s Head 74#1 but withdifferent cans and a different emitter resistor in the first gain stage.Awesome stuff.

*BC549C pinout is the opposite to that shown on the PCB, so flip them.

C1 1uC2 470pC3 47nC4 1uC5 470pC6 1uC7 1uC8 470pC9 1uC10 4n7C11 10nC12 100nC13 100nC14 100u

Q1 2N5089Q2 2N5089Q3 2N5089Q4 2N5089

D1 1N4148D2 1N4148D3 JumperD4 1N4148D5 1N4148

SUSTAIN 100kBTONE 100kAVOLUME 100kA

R1 39KR2 100KR3 470KR4 JumperR5 15KR7 1KR8 8K2R9 100KR10 470KR11 15KR12 JumperR13 8K2R14 JumperR15 470KR16 100KR17 15KR18 47KR19 47KR21 100KR22 390KR23 2K2R24 10K

CreamyDreamer

Test the board!

UNDER NO CIRCUMSTANCES will troubleshooting helpbe offered if you have skipped this stage. No exceptions.

Once you’ve finished the circuit it makes sense to test is before starting on the switch andLED wiring. It’ll cut down troubleshooting time in the long run. If the circuit works at thisstage, but it doesn’t once you wire up the switch - guess what? You’ve probably made amistake with the switch.

Solder some nice, long lengths of wire to the board connections for 9V, GND, IN and OUT.Connect IN and OUT to the jacks as shown. Connect all the GNDs together (twist them upand add a small amount of solder to tack it). Connect the battery + lead to the 9V wire,same method. Plug in. Go!

If it works, crack on and do your switch wiring. If not... aw man. At least you know theproblem is with the circuit. Find out why, get it working, THEN worry about the switch etc.

BATTERY

IN OUTYour nice, new circuit boardINCLUDING WIRED POTS!!!!

IN 9V GND OUT

Wiring shown above will disconnect the battery when you remove the jack plugfrom the input, and also when a DC plug is inserted.

The Board GND connections don’t all have to directly attach to the board. Youcan run a couple of wires from the DC connector, one to the board, another tothe IN jack, then daisy chain that over to the OUT jack.

It doesn’t matter how they all connect, as long as they do.

This circuit is standard, Negative GND. Your power supply should be TipNegative / Sleeve Positive. That’s the same as your standard pedals (Boss etc),and you can safely daisy-chain your supply to this pedal.

LED

BOARDOUT

BOARD9V

BOARDGND

BOARDGND

BOARDGND

BOARDINPUT

BATTERY

+IN

OUTLED

BOARDGND

BOARDLED+

+

Wire it up (if using a daughterboard please refer to the relevant document)

This template is a rough guide only. You should ensure correct marking of yourenclosure before drilling. You use this template at your own risk.Pedal Parts Ltd can accept no responsibility for incorrect drilling of enclosures.

FuzzDog.co.uk

Drilling templateHammond 1590B

60 x 111 x 31mm

It’s a good idea to drill the pot andtoggle switch holes 1mm bigger ifyou’re board-mounting them.Wiggle room = good!

Recommended drill sizes:

Pots 7mm Jacks 10mm Footswitch 12mm DC Socket 12mm Toggle switch 6mm

35mm

27mm