C...

 C.G. Conn

 C.Giant

 C.I.C

 C.M. Baker

 C.Q.O.

 Cactus

 Cage Amplifiers

 California Valveworks

 Caline Music

 Calypso FX

 Cannoy Guitars

 Canor

 Captain FX

 Carella Guitars

 Carl Martin

 Carl's Custom Guitars

 Carlin

 Carlos

 Carlsbro

 Carlson

 Caroline Guitar Company

 Carr

 Carrotron

 Carvin

 Casey Gooby

 Casimir Effects Pedals

 Casper Guitar Technologies

 Castle Instruments

 CastleRock

 CAT Sound

 Cat's Eye ESP

 Catalinbread

 Cause & Effect Pedals (CE Pedals)

 Cavagnolo

 Cave Passive Pedals

 CBS-Arbiter

 Celestial Effects

 Celmo

 Century

 César Diaz

 CGM Custom Shop

 Chamber Of Sounds

 Champ Electronics

 Champion

 Chandler

 Chandler Limited

 Chapter 53 Boutique Effects

 Charlie Hall

 Chaser

 CheeseBlocks Effects

 Chellee Guitars

 Cherub Technology

 Chicago Iron

 Chikipick

 Chiu Luen (DongGuan) Electronics

 Chord

 Chorus

 Chris Custom

 Chris Mac Gregor

 Chuck Levin's Washington Music Center

 Chuck's Tone Garage

 Chucktone Effects

 Chunk Systems

 Ciclar

 Cicognani

 CIOKS

 CircuitFX

 Circular Time Hardware

 Clac!

 Clark Amplification

 Classic Cantabile

 Clay Jones

 Claybridge Sound Systems

 Clayton

 Click Pedals

 Climb

 ClinchFX

 Clone Bro

 Cloud 9

 Club Of The Knobs

 Cluster Effects

 CMATMODS

 CMI

 Cobrahawk

 Code

 Codtone

 Coffin Case

 ColdCraft Effects

 Coleman

 Collins

 Colorsound / Sola Sound

 ColorTone Fx

 Columbus

 Combustible Man Effects

 Comet Effects

 Commune

 Commune/ECA (Empire Custom Amplification)

 Companion

 Compulsive Audio

 Concert

 Conrad

 Cool

 Cool Bear Effects

 Coolmusic

 Coolpedals

 Coolsound

 Coopersonic

 Copilot FX

 Copper Gear

 Coron

 Correct Sound

 Cort

 Cortez

 Cosmic Sound FX

 Cosmosound

 CostaLab

 Countryman Associates

 Coura

 Covington Guitar Effects

 Coxx

 Crafter

 Cranetortoise by Albit

 Crate

 Crazy Tube Circuits

 Crazybox Pedals

 Creation Audio Labs

 Creepy Fingers

 Créer

 Crest

 Crestwood

 Crews Maniac Sound

 Critically Overdriven

 Crock

 Cromwell

 Crossfire

 Crown

 Crowther Audio

 Crucial Audio

 Crushsound

 Cruze

 Cruzer (by Crafter)

 CSL

 CSR

 CTech / CB Labs

 Cubist Effects

 Culler Amplification

 Curetronic.de

 Cusack Music

 Custom 77

 Custom Audio Electronics

 Custom Guitar Gear

 Custom Guitar Innovations

 Custom Guitar Tone

 Custom Tones

 Cutec

 Cyclone

 Cyndustries Cynthia

 Dennis Cornell

 Effetti Di Clara

 H. W. Cano Electronics

 Paul Cochrane

 Pete Cornish

 Theremaniacs / Chuck Collins

 Tim Champion Guitar Pedals