| Atma-SphereŽ | Tube OTL Amplifiers |
| Audio Professor | Tube Amplifier Kits |
| Audio Technik | Triode Class A OTL Tube Amplifiers |
| Berning | Tube Amplifiers |
| Cassiopeia - Audio Einstein | Tube Amplifiers |
| Croft Amplification | Tube Amplifiers |
| David Berning | Tube Amplifiers |
| Einstein | Tube Amplifiers, Tube CD Players |
| Einstein | Tube Amplifiers |
| Graaf | OTL Tube Amplifiers, Tube Amplifiers |
| Kora | Tube Amplifiers, DAC's |
| Mactone Corp. | OTL Tube Amplifiers from Japan |
| Records UnlimitedEquipment | Vinyl Records, OTL Tube Amplifier |
| SAP | Tube Amplifiers, Speakers |
| SD Sound | Tube Amplifiers |
| Silvaweld Audio Lab. | Tube Amplifers |
| Tenor Audio | OTL Tube Amplifiers |
| Transcendent Sound | OTL Tube Amplifiers, Kits, Books, BBS |
| Ultrasound | Tube Amplifiers |
| WooAudio | Tube Headphone Amplifiers |