12AX7 / ECC83 Vacuum Tube – High-Gain Preamp Tube for Guitar Amps & Hi-Fi

The 12AX7 (ECC83) is the highest-gain common dual triode in guitar amp preamp stages, also widely used in hi-fi and phono preamps.

• Tube type: High-mu dual triode
• Base: B9A / Noval 9-pin
• Heater: 12.6V AC (0.15A) or 6.3V AC (0.3A wired parallel)
• Typical use: Preamp gain stages in Fender/Marshall-style guitar amps and hi-fi/phono preamps

ECC83 equivalent — interchangeable in amps calling for either designation.