| H.J.Leak and Co. Ltd. | History about Leak Tube Amplifiers |
| H.-T. Schmidt | Museum, Collection, Information about Tubes |
| Hadley Records | Tubes |
| Hagerman Technology LLC | Tube Amplifiers, Tube Testers |
| Hairball Music | Tube Guitar Amplifiers |
| HAJDINJAKLABS | Tube Amplifiers |
| Hal | Tubes |
| Halfin S.A. | Tubes, Forum |
| Ham Radio USA - Trading Post | Links, Events |
| Hammer Dynamics | Speakers |
| Hammers Homepage | DIY Speakers |
| Hammond Mfg. Co. (Electronics Group) | Racks, Transformers, Power Bars |
| Hanazawa's Junk Page | Vintage Audio |
| Handmade Audio Transformers | Transformers |
| Handmade Electronics | Tubes and Parts |
| Hans pages! | DIY Tube Amplifiers |
| Harmonic Discord | Forums |
| Harmonictech | Cables |
| Harmonix by Combak | Tube Amplifiers |
| Harmony Central® Main Menu | Information, forums, Links |
| Harold Layer | Ham Radio |
| HARPER Amplifiers - Swiss design | Tube Guitar Amplifiers |
| Harper's Guitars | Tubes, Tube Guitar Amplifiers |
| Harry Hibma | DIY Tube Audio |
| Harry's Boatanchor Pages | Ham Radio |
| Hasimoto Transformers | Transformers |
| HAUTE-FIDELITE | French Audio Magazine |
| 'HAWK' High End Audio Equipment | Tube Amplifier Kits |
| HB9BBD - Amateur Radio Moonbounce | Amateur Radio Site |
| HB-AmpDesign | Tube Amplifier Kits, Tubes, Parts |
| HDB audio | Tube Electronics for Professionals |
| HeadWize | Headphone Resource Site, forum |
| Heart Audio | Tube Amplifiers, Tube CD Players |
| Heart Land | Ham Radio |
| Hearth Guitar Amplifiers | Tube Guitar Amplifiers |
| Heathkit Schematic Library | Schematics |
| Heathkit Virtual Museum | Tube Amplifiers |
| Hello, Mister Valve! | Information about tubes, Tube Boxes |
| Helmut Singer Elektronik | Tubes |
| Helthansen | Information about Tube Audio - Articles |
| Hensler-Kabel | Cables, Transformers |
| Herbie's Audio Lab | Vacuum Tube Damping Instrument |
| Herron Audio | Tube Preamplifiers |
| Herweijer Electronics | DIY Tube Audio |
| HF-shop | Tubes |
| HI Fi Trials | DIY Tube Audio, Tube Amplifiers |
| Hi Fidelity Audio | Retailer |
| Hickok | Tube Tester Manual |
| HiFi | Online Magazine, Forum |
| HiFi - Audio - High End | DIY Loudspeaker site, Tube Amplifiers |
| HiFi - Audio - Video - Selbstbau - CarHiFi - Diskussionen bei audiomap.com | German Audio Forum, Links |
| Hifi - link . dk Lyd | Online Magazine |
| Hifi & Music Board Russia | Forum |
| Hi-Fi Audio Kits on the web! | Speakers |
| Hi-Fi audiophile Amplificateurs à tubes haut rendement | Tube Amplifiers |
| HiFi China | Online Magazine |
| Hifi Choice | Audio Magazine, Forum |
| Hi-Fi Choice | Tube Amplifiers, Shindo Lab. Retailer |
| Hi-Fi Forum - Distributors of Fine European Audio Equipment | Pathos Hybrid Amplifier |
| Hifi John's Home | DIY Tube Audio |
| Hi-Fi News & Record Review | Audio Magazine |
| Hi-Fi News and Record Review Accessories Club | Tubes and Audio Accessories |
| hifi on TNT-Audio | Online Magazine |
| Hifi Plus | Audio Magazine |
| Hifi Speaker Design | Information |
| HI-FI World Magazine | British Audio Magazine |
| Hifi2die4 | Links |
| HiFi-Analyse | Tube Amplifiers, Retailer |
| hificollective | Tube Amplifier Kits, Parts |
| Hifi-Forum.de | Forum |
| Hi-FiGuide - Internet Edition - Rivista di Hi-Fi, Musica e Cultura | The Italian Guide to Esoteric Hi-Fi and International High-End |
| Hifilit | Museums |
| HiFi-Music-World 2004 | DIY - Fair |
| Hifi-Notes | Audio Information from Benelux |
| Hifisound der Lautsprecherspezialist | German Speaker Distributor |
| hifitubes.de | Tubes |
| Hifizeile | Retailer |
| High End Audio | Retailer |
| High End Audio Repair | Tube Amplifier Service |
| High Fidelity | Audio Information |
| High-End Audio | Tubes |
| Highend Audio und Hifi auf highendaudio.de | German based Audio Information Platform |
| Hinkel-Elektronik | Parts |
| Hinoki | DIY Tube Amplifiers |
| HI-TEK Electronics | Parts |
| Hobby Hifi | German DIY Audio Magazine |
| Hoffman Tube Amplifiers | Tube Guitar Amplifiers, Parts, Forum |
| Hoffmann Amplification | Tube Guitar Amplifiers |
| Holborne audio instruments | Tube Amplifiers |
| Home on the Range | DIY Speakers |
| Homebrew Tube Amp Corner | DIY Tube Audio |
| homebrew, digital tecniques and contest | Ham Radio |
| homegrown audio pure silver cables | Cables |
| Homemade Tube Audio Index | DIY Tube Amplifiers |
| Hong Kong Tube Audio Club | Hong Kong based Audio Information Platform |
| Horchaudio | Tube Microphones |
| Hörerlebnis | German Audio Magazine |
| Horn + DIY[Timo Christ] | DIY Horn Speaker site |
| Hornmanufaktur | Speakers |
| hOrnZ acoustics | Speakers |
| Hot Glass Audio | Tube Amplifier Service |
| House of Jim | DIY Tube Audio, Tube Guitar Amplifiers |
| House of Tubes | Tubes |
| Housenn Tube Audio Equipment | Tube Amplifiers |
| Hovland Company | Tube Preamplifiers, Cables, Interconnects |
| Hssfidelity | Car Tube Preamplifiers, Capacitors |
| Huculak Andrew | Speakers, Cables |
| Hughes and Kettner | Tube Guitar Amplifiers |
| Hugh's Ominous Valve Works | Tube Boxes |
| Hullett Amplifiers | Tubes |
| Hullett Amps | Tube Guitar Amplifiers |
| Hurricane Amplifiers | Tube Guitar Amplifiers |
| Hyousi | DIY Tube Amplifiers |