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.
Machmat Tube
Information about tubes. Tube datasheets, schematics, code explanation, and sales.
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.
Valvotronics
Manufacturer of high end tube audio electronics, including the Gain Ryder 3 compressor.