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. Additionally the tubes undergo a battery of tests for basic performance characteristics and faults such as: Emissions, Transconductance, H-K and Grid leakage, etc... If a tube does not pass our strict performance criteria it's tossed or sent back to JJ Electronic for evaluation.
The JJ ECC832 is a true to spec 12DW7 replacement. These tubes also make great low gain substitutes in the right applications. You'll find these in several of our Low Gain and Blues Option Full Retube Kits. You'll also see them in Harp specific kits where we use them to actually unbalance long tail phase inverter circuits which promotes more even order harmonic distortion.
For the technical guys:
Pins 1-2-3 are the low gain side (12AU7/ECC82 spec).
Pins 6-7-8 are the high gain side (12AX7/ECC83 spec).
We now also have the JJ ECC823 which is the same tube with the triode configuration reversed.
