We refer to the tubes and their positions in the amp as V1, V2, etc. for preamp tubes and P1, P2, etc. for power tubes. The number indicates the position of the tube as counted from right to left when looking at the back of the amplifier. The right to left progression follows the circuit from input to output.
||12AT7||5751 or (12AX7 okay)||12AT7EH||12AX7EH|
|Manufacturer||TAD||TAD||Electro-Harmonix||5751 - TAD or
|Function||1/2 Push-pull power stage||1/2 Push-pull power stage||Phase inverter and tremolo oscillator||Reverb return and mix||Reverb send||Initial gain stage, post tone-stack recovery|
The Impala is a fixed bias amplifier and requires a bias adjustment whenever the power tubes are changed. See the Impala Owner's Manual for more information on adjusting the bias.
Please use well-matched pairs of power tubes for maximum performance and minimum hum in triode mode.The Impala can only use matched pairs of 6L6, 5881, or 7581A power tubes.
Carr Amplifiers selects and tests the finest current production tubes specifically for each amplifier model. Caution should be used when buying replacement tubes from any dealer who does not have a return policy as all tubes can have problems (NOS tubes are susceptible to microphonics and failure too).