| Althea Musica | Tube Amplifiers |
| ANTIPHON AUDIO LABS | Tube Amplifiers, Tube DAC |
| Ardency Audio | Tube Amplifiers |
| Audiomusic | Forum |
| AudioTropic | Tube Amplifiers |
| Chicago Joe's Tube Information Page | Tube Databases |
| DPF audio | Tube Amplifiers |
| Ex.Field | Tube Amplifiers |
| Funky Junk France | Tube Electronics for Professionals |
| GG Audiodesign | Tube Amplifiers |
| GREENSTONE USA | Tubes |
| Guytronix | Tube Guitar Amplifiers, Tube Amplifier Kits |
| Hi Fidelity Audio | Retailer |
| Hornmanufaktur | Speakers |
| Jinvina Audio Company | Tube Amplifiers |
| KAVD | Tube Hybrid Amplifiers |
| LABTEK | Tube Amplifiers |
| Lamphear Electronics | Tube Amplifiers |
| Leben | Tube Amplifiers |
| Low Power Radio | Tube Electronics for Professionals, AM Transmitter |
| McAlister Audio | Tube Amplifiers |
| Michael's Village Music | Tube Amplifier Service, Vintage Tube Audio Equipment |
| NJ7P Tube Database Search | Tube Database |
| NVE | Tube Amplifiers |
| Olionik | Tube Amplifiers |
| Orator | Tube Amplifiers, Speakers |
| Röhren und hören | Forum |
| SECA-Consulting | Tube Amplifiers |
| Shorelineamps | Tube Amplifiers |
| Sound Fusion | Speakers |
| Speaker Hifi | Speaker |
| SPECIAL PURPOSE TO JAN TUBE TYPE CROSS REFERENCE | Tube Database |
| Taticaudio | Tube Amplifiers |
| TUBEWONDER | Tube Guitar Amplifiers |
| Twincats | Tube Amplifiers |
| Vacuum Tube Supply | Tubes |
| Viva | Tube Amplifiers |