Preamp tube characteristics

Tube mA TC Mu (gain)
12AX7 ECC83 7025 1.2 1600 100
12AT7 ECC81 10.0 5500 60.5
12AY7 3.0 1750 44
12AU7 ECC82 10.6 2200 17-20

mA is current in milliamps. This is standard 1957 industry spec at standard test reference voltage and bias settings.

características de los tubos o válvulas del los pre-amplificadores.