The JJ ECC83S is a High quality, low
noise replacement for any 12AX7 type tube. These are available graded for High Gain and also available with current Balanced triodes for phase inverter use and Balanced and Matched in pairs or multiples.
All our preamp tubes are stringently tested for noise and microphonics using Amplitrex testers driving an external amp. There is no extra charge for low noise and microphonics testing like with other tube vendors. If a tube does not pass our strict performance criteria it's tossed or sent back to JJ Electronic for evaluation.