| Audiokit | Tube Amplifier Kits, Speakers, Parts, Tubes |
| Farnell | Parts, Tools |
| Fuller Metric Parts | Screws |
| Lyn-Tron, Inc | Standoffs, Screws |
| Oppermann Electronic | Parts |
| Parts Connexion | Parts |
| PK Precision Machining Inc | Screws |
| TAD - The Tube Amp Doctor | Tubes, Parts |
| Tube Amp Doctor GmbH | Tubes |
| Welborne Labs | Tube Amplifier Kits, Tubes and Parts |