The JJ 5881 is a high quality valve for both guitar and hi-fi amplifiers.
It has a power rating of 23 watts and is a traditional 'stubby bottle' design. They are punchy and warm in the midrange and with plenty of jangle and will break up sooner than a 6L6.
In an adjustable fixed bias 6L6 based amps you will have to adjust your bias to suite the lower power rating of 23 watts. In cathode biased amps you may need to possibly change the cathode resistor to keep within the plate dissipation of 23 watts.
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.
These are Platinum Matched & Tested with state of the art digital & analogue measuring equipment for
- Current (ma)
- Transconductance (gm)
- Emission Quality
- Grid Leakage