12AX7 is a miniature dual triode tube with high voltage gain.The 12AX7 is a high-gain (typical gain factor 100), low plate current triode, and is therefore best suited for use in the preamplifier (input and mid-level) stages of audio amplifiers, guitar amps , mic preamps etc.
Also known as a ECC83 &7025
Download a pdf file of gain comparison of current production 12ax7's here
For a sound demonstration of various 12ax7's with clean Fender tones go here
For a sound demonstration of various 12ax7's with dirty Marshall tones go here
