5751 Vacuum Tube – Reduced-Gain Preamp Triode for Guitar Amp Headroom

The 5751 is a ruggedized dual triode built to the same footprint as the 12AX7 but with roughly 70% of its gain, giving a cleaner, higher-headroom preamp stage without a circuit change.

• Tube type: High-mu dual triode (reduced-gain)
• Base: B9A / Noval 9-pin
• Heater: 12.6V AC (0.15A) or 6.3V AC (0.3A parallel)
• Typical use: Drop-in 12AX7 preamp-socket replacement in guitar amps for players wanting later breakup and lower noise

Originally a military/industrial spec (JAN) tube built for long service life.