12BH7-A Gold Pin Balanced and Matched

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.