JAC-Music
- Provides information about electron tubes products, support, distributor adresses, datasheets and sells tubes parts.
- http://www.jacmusic.com/

D.Klimo
- Manufacturer of a variety of high end tubes. Germany.
- http://www.dklimo.de/

Hot Glass Audio
- Repair, modification and restoration of vintage, vacuum tube audio equipment such as tube amplifier.
- http://hotglassaudio.com

MagneQuest
- Makes tube audio transformers such as air-gapped and parallel feed single-ended transformers.
- http://www.magnequest.com/

JJ Electronic
- Manufacturers of tubes, capacitors for high-end audio amplifiers. Base in Slovak republic and Canada.
- http://www.jj-electronic.sk/

M.V.S.Z AO Svetlana
- Manufacturers of high end electron tubes Svetlana 300B and Svetlana EL509-II.
- http://www.svetlana-mvsz.com

Zeitmann tubes
- Manufacturers of vacuum tubes such as NOS Tungsram audio tubes.
- http://www.zeitmann-tubes.com/

PAEng Design
- Devoted to vacuum tubes world applied to audio science. Consulting, design and engineering in audio. Power amplifiers and Hi-End products.
- http://digilander.libero.it/paeng/

THL
- Supplier of audio parts and DIY kits. Taiwan.
- http://www.thlaudio.com/

Greenstone USA
- Manufacturer and distributor of vacuum tubes and capacitors for audio, broadcast and military applications.
- http://www.greenstoneusa.com

Gabriel Sound Garage
- Make a 18 watt tube guitar combo amplifier. Images, blueprints, tips & tricks.
- http://mamaliga.com/gabriel/

Audio Kit Mania
- Distributor of tube and related products to design and build custom amplifiers and systems.
- http://www.audiokitmania.com/

Variable Voltage Technology Ltd
- Transformers power supplies and related equipment for audio equipment. Also EL inverters and magnetron transformers. UK.
- http://www.vvttransformers.co.uk

Watford Valves
- Suppliers of tested, graded and guaranteed valves to the professional music industry. UK.
- http://www.watfordvalves.com/

Valvotronics
- Manufacturer of high end tube audio electronics, including the Gain Ryder 3 compressor.
- http://valvotronics.com/

Machmat Tube
- Information about tubes. Tube datasheets, schematics, code explanation, and sales.
- http://www.machmat.com/

Maxi-Test Company
- Digital tube testers for matching and testing power pentode vacuum tubes used in musical equipment amplifiers.
- http://maximatcher.com/

David Berning Company
- Manufactures a series of vacuum tube audio amplifiers based on impedance converter that replaces the traditional audio-output transformer. Italy.
- http://www.davidberning.com