Bugera 12AX7B tube

General

Since the invention of the amplifier, tubes have been the most fascinating components of electronic sound technology. You don't need to be an audiophile to know that the type of tube in your favourite amplifier plays a huge part in shaping your sound. This is why Bugera offers you a large number of premium valves that are manually selected to match the tonal preferences of musicians.

They offer tubes with the Californian sound as well as valves with a distorted British grind, for instance. The different preamp tubes are a great addition to your amplifier's sound, while offering little noise an a minimum of microphonics.

There's one thing all amp tubes have in common, and that is the air-tight quality control they are subjected to before being shipped to you. When Bugera says that their tubes are manually selected, they mean that each Bugera tube is individually tested. Tone is everything for you, which is why Bugera do all they can to make sure their tubes offer a truly warm sound.

The 12AX7 is a miniature dual triode vacuum tube with high voltage gain. The tube is mostly known for its distinct tube sound. The 12AX7 is a high-gain (typical gain factor 100) low-plate current triode, making it excellently suited for low-level audio amplification. That is why it is mostly used for preamp (input and mid-level) stages of audio amplifiers. The 12AX7 triode features a high-value plate resistor with a 100kOhm impedance. Grid power usually comes from a cathode resistor. Even though the 12 in the model number implies it requires a 12-volt heater system, the tube has a centre-tapped filament so that it can also be used in 6.3V or 12.6V heater circuits.

• see the manual for replacing tubes in Bugera guitar amplifiers