The KT66 is a high quality valve for both guitar and hi-fi amplifiers. It is a beautiful looking valve.
They are a KT66 GEC replica made by Shuguang and then tested and graded by Tube Amp Doctor (TAD) in Germany.
We then carry out our own testing and grading regime as specified below.
Platinum Matched & Tested
All our power-amp valves are burned in under load on our burn-in racks for at least 24 hours. The filaments are powered and voltage is also applied to the plate to simulate real use. The reason we do this is get rid of any faulty or weak valves and as a pre-grading process to allow the plate/grid mechanism to relax into it's rest position. Tiny differences in construction make for enormous differences in electrical characteristics, and thus if a valve is graded after it's been burned in then the measured characteristics hold true over its lifespan to a greater extent.
This seems simple but it's amazing how many vendors ignore it. It's the reason so many people complain about poorly graded valves.
The Power amp valves are Platinum Matched & Tested with state of the art digital & analogue measuring equipment for
- Current (ma)
- Transconductance (gm)
- Emission Quality
- Grid Leakage