Vol. 15: Stomp Box Basics: Tremolo and Fuzz

Simple guitar effects circuits you can build.

+ Downloads & Extras:

Hot Stomp Box Mods

Since the ancient times, guitarists have modded their amps and pedals in search of that killer tone to rock your socks off.

Most of the electronic circuits in stomp boxes are in the public domain, unpatented and ripe for hacking. The legendary Ibanez Tube Screamer overdrive alone (Stevie Ray Vaughan, Carlos Santana, Trey Anastasio) has inspired countless clones and popular DIY modifications to its basic op-amp goodness. Even pedal pioneers Roger Mayer (Jimi Hendrix, Jimmy Page, Stevie Wonder, Bob Marley) and Pete Cornish (Pink Floyd, Queen, Black Sabbath, Dire Straits, the Police, the Pretenders) started by modding existing equipment to find new sounds.

The explosion of DIY websites since the 1990s has helped thousands of makers to invent new effects or upgrade vintage ones; some modders now sell their own boutique stomp box brands, such as “Analog Mike” Piera (analogman.com).

We asked some DIY pedal experts what’s hot in stomp box mods today.

TOP 4 EASY STOMP BOX MODS
from Jack Orman of AMZFX (muzique.com)

Swap op-amps.
Switch your fuzz pedal’s RC4558 for a TL072 for a clearer, crisper tone. Both are standard pin configuration, dual op-amp chips, and there are many more available that are direct drop-ins.

Change gain.
Substitute higher-gain transistors (like a 2N5089) for lower-gain devices (2N2369), or vice versa. There are thousands to choose from. Just stick with NPN for NPN, or PNP for PNP.

Switch diodes.
Change the clipping diodes in fuzz pedals to different parts, such as 1N4001 for 1N4148, or even substitute germanium diodes or LEDs for silicon. This almost always yields tone variations that can be noticed, even by someone new to DIY.

Boost voltage.
Upping the voltage supply from 9V to 12V or even 18V can provide increased clean headroom and remove some of the muddy sound that may be cluttering the pedal’s tone. Just make sure the capacitors are rated for 25V or higher.

BEST STOMP BOX WEB RESOURCES

• redcircuits.com Flavio Dellepiane’s schematics for effects and more.
• generalguitargadgets.com J.D. Sleep’s highly informative site, with kits and schematics.
• runoffgroove.com A great DIY site with schematics, PCB layouts, and rocking MP3 sound samples for dozens of pedal circuits.
• olcircuits.com Ready-to-build DIY kits for making pedals from Runoff Groove and more.
• diystompboxes.com Aron Nelson’s excellent site for building and modding effects, with forums, wikis, schematics, and more.
• geofex.com R.G. Keen’s site with techniques, tutorials, schematics, PCB layouts, more.
• muzique.com Jack Orman’s AMZFX site with schematics, tutorials, blog, and germanium transistors and custom PC boards for sale.
• gaussmarkov.net Paul Ruud’s cool DIY guitar effects.
• hammer.ampage.org Mark Hammer’s site with schematics for dozens of mods, DIYs, forums, and more.

WHERE TO GET PARTS

• GeneralGuitarGadgets.com for printed circuit board (PCB) layouts or ready-to-solder board (RTS) for effects
• Small Bear Electronics
• FutureElectronics
• Mouser Electronics for transistor sockets 151-TO-1832OG, 151-TO-4320G, and 151-TO-18320G

STOMP BOX BIBLES

• Electronic Projects for Musicians by Craig Anderton
• The Stomp box Cookbook by Nicholas Boscorelli out of print, it now fetches hundred of dollars
• Analog Man's Guide To Vintage Effects by Tom Hughes with "Analog Mike" Piera formusiciansonly.com
• How to Modify Guitar and Bass by Brian Wampler

—Keith Hammond

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