Aprilsound: Audiophile audio transformers and accessories.
Audio Kit Mania: Distributor of tube and related products to design and build custom amplifiers and systems.
D.Klimo: Manufacturer of a variety of high end tubes. Germany.
David Berning Company: Manufactures a series of vacuum tube audio amplifiers based on impedance converter that replaces the traditional audio-output transformer. Italy.
Gabriel Sound Garage: Make a 18 watt tube guitar combo amplifier. Images, blueprints, tips & tricks.
Greenstone USA: Manufacturer and distributor of vacuum tubes and capacitors for audio, broadcast and military applications.
Hot Glass Audio: Repair, modification and restoration of vintage, vacuum tube audio equipment such as tube amplifier.
JJ Electronic: Manufacturers of tubes, capacitors for high-end audio amplifiers. Base in Slovak republic and Canada.
M.V.S.Z AO Svetlana: Manufacturers of high end electron tubes Svetlana 300B and Svetlana EL509-II.
Machmat Tube: Information about tubes. Tube datasheets, schematics, code explanation, and sales.
MagneQuest: Makes tube audio transformers such as air-gapped and parallel feed single-ended transformers.
Maxi-Test Company: Digital tube testers for matching and testing power pentode vacuum tubes used in musical equipment amplifiers.
PAEng Design: Devoted to vacuum tubes world applied to audio science. Consulting, design and engineering in audio. Power amplifiers and Hi-End products.
THL: Supplier of audio parts and DIY kits. Taiwan.
Valvotronics: Manufacturer of high end tube audio electronics, including the Gain Ryder 3 compressor.
Variable Voltage Technology Ltd: Transformers power supplies and related equipment for audio equipment. Also EL inverters and magnetron transformers. UK.
Watford Valves: Suppliers of tested, graded and guaranteed valves to the professional music industry. UK.
Zeitmann tubes: Manufacturers of vacuum tubes such as NOS Tungsram audio tubes.