12AX7 Tubes: The Complete Buyer and Replacement Guide
A 12AX7 is a high-gain dual triode preamp tube with an amplification factor of 100, used in virtually every guitar amp, hi-fi preamp, and studio device built since the 1950s. Last updated: May 2026 Amplification factor 100. That single number explains why the 12AX7 shows up in the preamp section of almost every tube amp…