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...
Further, all of our ECC99's undergo a lengthened test duration to insure stability and accurate test results (as is necessary with all high current pre's).
If a tube does not pass our strict performance criteria it's tossed or sent back to JJ Electronic for evaluation.
The JJ ECC99 is a proprietary driver tube designed for Hi-Fi use and used in JJ's own stereo amp applications. It's similar to a 12BH7A (same pin out: 9A) but with increased plate current and higher limiting values.
For most standard driver/input applications our standard selection is suitable. For stereo or parallel driver applications refer to our Balanced options.
