H...

 Dave Hall Amps (DHA)

 F. Hübner

 Gary Hurst

 H&H Electronics

 H. W. Cano Electronics

 Halcyon Humanoid Pedals

 Halifax

 Haller

 Hallmark Guitars

 Hamilton Music

 Hammond

 Hamony

 Handmade Concept

 Handmade In Concert

 Handwired-Effects

 Hanum

 HAO

 Happy Snake

 Harden Engineering

 HardWire by DigiTech

 Harley Benton

 Harrison Instruments

 Hartke

 Hartman

 HaTeNa Effectornics Engineering

 Haunting Mids

 Hayashi Craft

 Hayden

 HAZ Laboratories

 HCFX (Harmony Central Effects Forum)

 Heathkit

 Heavy Electronics

 HedgeHog Stompboxes

 Heil Sound

 Hello Sailor Effects

 Henretta Engineering

 Heptode

 Hermida Audio

 Herrnsdorf

 Hexe Guitar Electronics

 Hfx

 HG Effectz

 Hi-Max

 High-Kit

 Highfield

 Hillwood

 Hilton Electronics

 Himmelstrutz Elektro Art

 HIP

 HipKitty Products

 Hitone Electronics

 Hiwatt Amplification

 HMB-TEC

 Ho.Dox Custom Design

 Hobbertt

 Hochwälder Effekt Manufaktur

 Höfner

 Hohner

 Holden

 Hollytronics

 Holmes

 Holowon Effects

 Holy Custom Pedals Amps

 HomeBrew Electronics (H.B.E.)

 Homebrew Electronics TN / M.A.D. Effects

 HomeRecords

 Honda Sound Works

 Honey

 Hopper Pedals

 Horst Musical Instruments

 Hot Amplifiers

 Hot Boxx

 Hot Chili Tube Company

 Hot Wire Audio

 Hot-Box

 Hotone Audio

 Hovercraft

 Hoxton Owl

 HR Legend Effects

 Hudson Electronics UK

 Hughes & Kettner

 Human Gear

 Hump/Back Engineering

 Hungry Robot Pedals

 Hurricane

 Hutchins

 JHS - Hornby Skewes

 Jimi Hendrix System

 Marion Henry Electric

 Morgan Hill

 S. Hawk Limited

 博多 (Hakata)