Guitar Effects Construction Basics

Overview

This page has a sort-of introduction to guitar effects pedal construction.

Last updated: 2010-10-06
Created: 2002?

Common Parts You'll Need

Electronic Parts

Resistors

Get 1/4-watt, 5% carbon composition tolerance for most purposes. Get a few metalized film 1% tolerance resistors for noise-critical applications...be warned, they may affect your effect's sound. Start with 10 carbon-comp resistors of each of the following values

47ohm
100ohm
220ohm
330ohm
470ohm
560 ohm
680 ohm
1K
2.2K
3.3K
4.7K
5.6K
6.8K
8.2K
10K
22K
33K
47K
56K
68K
100K
220K
470K
500K
1M
2M
4.7M

Potentiometers:

adjustable resistors, get as many as you can afford of each of these values. Get mostly audio (logarithmic) taper, but get some linear taper as well:

1K
5K
10K
25K
50K
100K
250K
500K
1M
2M

Capacitors.

You'll need mostly the ceramic and electrolytic varieties, and maybe a few polyester (for low noise critical apps) and non-polarized (depending on the projects you're doing). Start with 10 of each of the following values:

10pf ceramic
20pf ceramic
120pf ceramic
220pf ceramic
470pf ceramic
1000pf ceramic
.001uf ceramic
.0033uf ceramic
.005uf ceramic
.01uf ceramic
.022uf ceramic
.047uf ceramic
.05uf ceramic
.1uf ceramic
1uf electrolytic
2.2uf electrolytic
4.7uf electrolytic
10uf electrolytic
20uf electrolytic
100uf electrolytic (for power supplies)

LED's:

light emitting diodes, for lighting and signaling, they can be used in some cases where regular diodes are. Get whatever colors strike your fancy.

Diodes:

You'll need some silicon and some germanium varieties. They're used for power supplies and also in gain circuits. Each type has different tone. Get 10 of each of the following varieties to start with.

1N4148
1N914
1N4001

Transistors:

get NPN and PNP varieties, also some JFETs are handy. Get transistors in standard TO-92 case. Get some of each of the following varieties to start:

2N3904 NPN
2N3906 NPN
2N5485 JFET
NTE457 or 2N5457 JFET
2N5088 NPN
2N5089 NPN

Transistor sockets for TO-92 case, 4/$1 at All Electronics

IC's (integrated circuits):

Operational amplifier ICs, also known as op amps, are the building blocks of many guitar effects circuits. Get the following varieties to start:

TLO71 single lo noise op amp, DIP-8 package
TLO72 dual low noise op amp, DIP-8 package
TL074 quad lo noise op amp, DIP-14 package
NE5532 dual low noise op amp, DIP-8 package
LM833 dual low noise op amp, DIP-8 package
LF353N dual op amp, DIP-8 package
RC4558 dual op amp, DIP-8 package
RC4136 quad op amp, DIP-14 package
Get one or two CA3080 transconductance op amps

IC sockets: for changing out ICs, get DIP-8 and DIP-14, $0.20ea for DIP-8 at All Electronics

Other less-common components

Clairex CLM3000 optoisolator or equivalent. Check the Silonex website for similar/equivalent optoisolators/optocouplers. Used in many noise gate, compressor, phaser, and tremolo circuits. You can make your own using a photoresistor and a LED (see below).
Photoresistors. Get ones with low light resistance (less than 3K) and high light resistance (more than 1M). You can use these to build your own "optoisolators."

Hardware:

Cases: Hammond die cast aluminum cases are nice. You have a lot of options. You can even make cases from steel studs as described by R.G. Keen, if you're creative & mechanically inclined. A Hammond 1590BB (4.67" x 3.68" x 1.18") die-case aluminum case is $11 through Mouser.
Knobs: find whatever you like. Look for knobs with set screws.
Bolts, nuts, and washers: for mounting PC boards, jacks, etc. Get some lock washers too.
Rubber grommets--for cables & jacks, for use as strain reliefs or to ensure good jack fit in a case.

Wire

Hookup wire: small gauge is easiest to wire, anywhere between #22-#26; some people say "larger gauge sounds better", but it's harder to work with; you be the judge.
Shielded cable: RG-174 coax is good, available from Small Bear Electronics
Heat shrink--for insulating connections

Testing Equipment

Regulated power supply: Boss PSA-120 supplies 9V at 200mA. You'll find more flexibility, though, building your own regulated supply. Make sure you get whatever connectors you need to hook power up to the breadboard, if it makes it easier for you. You can even build a nice regulated power supply from a
Breadboard: useful for prototyping. Be sure to get some nice solid wire for hooking things up.
Digital volt meter. Useful for measuring resistances, voltages, current flow, and circuit continuity. Some can measure capacitance.
Volt meter probes: different kinds, from alligator clips to straight probes
Oscilloscope. Optional, good for looking at how effects circuits are affecting a waveform. You can find cheap ones on E-Bay all the time.

Connectors:

9V battery snaps
DC panel mount power jacks: use Radio Shack part#274-1582 or similar. 2.1mm inner dia. x 5.5mm outer dia. DC plug diameter is 2.1mm.; about $2 from Radio Shack. NOTE: when wiring these, remember that to be compatible with the "standard" Boss PSA-120 power supply, the "barrel" part should be positive (+) and the inner sleeve should be negative (-).
DC "barrel" power plugs: for building your own power supplies/daisy chains, if you're so inclined. Or, you can just go out and buy a Boss daisy chain, might be easier. 2.1mm inner dia. x 5.5mm outer dia., about $0.75 each.. Again, remember "barrel" part should be positive (+) and the inner sleeve should be negative (-) (see above).
Jacks: get 1/4" stereo phone jacks, and maybe some 1/4" switched mono phone jacks, about $1.50-$2.50 each

Switches

SPST toggle
SPDT toggle, $1.35 from All Electronics
DPDT toggle, $1.75 from All Electronics
DPDT heavy duty pushbutton "stomp" switches--necessary to implement true effect bypass, around $8-15/each, from Small Bear Electronics or other sources.
3PDT stomp switches, various sources; these are best for using true bypass AND controlling LED display...very versatile, and about $13 from Stewmac.com

Hand and Power Tools

Soldering Iron, about $30 for a cheapie, 25W - 40W is sufficient.
Solder, 60/40 rosin core, $10 will last you a while
Sponge--for wiping off soldering iron, $2 from grocery store
Desoldering tool: some kind of device to suck up solder, either plunger-style or solder wick, $7 from Radio Shack
Drill--for drilling holes in cases; drill presses are better but more $$, $40 and up. Drill Presses are about $70 at Harbor Freight.
Tapered reamer: sometimes more handy than a drill, $4 at Harbor Freight Tools
Drill bits--from really small (for drilling holes in PC boards) to pretty large (for drilling holes for pots, jacks, and stomp switches). Get #50 (.070"), #60 (.040") and #70 (.028") to start; you can buy an 8pc "Circuit Maker" kit for $20 from http://www.store.yahoo.com/drillcity/
Drill Press-for drilling holes in PC boards. Or get a Dremel MotoTool and the Drill press adapter stand. About $50 from Walmart or Home Depot.
A flat mill file and a few round files--for filing burrs off of boards, cases, etc., $5-10 total from hardware store or Harbor Freight
Utility knife--for cutting things and scoring boards, $2
Metal square--for drawing nice right angles, $5
Painting supplies--for finishing your case, varies
Small, thin needlenose pliers (see below)
Small diagonal cutters, $20 for a small head pliers kit for from hardware store
A good set of screwdrivers, from jeweler's to regular size, both philips- and slot-head, $5
A set of ratchet wrenches for tightening down bolts, $20 from a hardware store for a starter set
A workbench somewhere with good lighting.

PC Board Creation:

Layout Items

Express PCB Layout software (free from website)
Adobe Photoshop (for adjusting PDF files)
Adobe Illustrator (optional; for printing for layout; could be done in Photoshop too, but easier in Illustrator)
Adobe PDFWriter (comes with purchased Acrobat, for outputting from ExpressPCB in usable format)
Toner Transfer Sheets (for transferring circuit onto copper PC board blank), made by Techniks, $12 for (5) 8.5x11 sheets, from All Electronics
Laser printer (for printing onto toner transfer sheets); go to Kinko's if you have to, with your Illustrator and/or Photoshop file.

Etching Items

Board etchant (powdered ferric chloride); $4, makes enough to etch about eight (8) 4x6 boards, from All Electronics
One-sided PC Board blanks; 4"x6" $2 from All Electronics
Small flat file or stone (for eliminating burrs on edge of board); $2 from hardware store
Iron (for heating the design to transfer it to the copper); $10
Sharpie permanent marker (for fixing broken traces, etc. before etching); $2
Rubber gloves (for handling ferric and paint thinner); $3
Paint Thinner/Hexane/Mineral Spirits (for cleaning off pattern after etching); $4 for a pint
A plastic or glass container (for cleaning off pattern after etching)
A plastic container for etching (big enough to etch board and to stir etchant without it spilling; 6"W x 12"L x 4"H Tupperware container for $5 at a grocery store).
Plastic spoon/fork (for stirring etchant & lifting board out); get one at your local fast-food restaurant
Steel wool or synthetic steel wool (for cleaning off pattern after etching); $3 will last a long time.

Miscellaneous Things (handy things to have around)

9V batteries
Magnifying glass
Alligator clips--good for testing and qucik hookups
Spray adhesive--for gluing aluminum foil inside a case as a shield
Heavy duty aluminum foil--makes great shielding inside guitars and in effects boxes
"Sharpie" permanent markers
Electrical tape
Paper towels