The GEC a2900 is an incredibly rare 12AT7 variant. It is a fairly large departure from a traditional 12AT7 because of the large plate structure. Its sound is pure, with a realistic mid-range and extension in both directions. This is widely considered to be the best 12AT7 ever made. We have 4 available and we can make matched pairs if requested.
All tubes are tested on a AT1000 computerized tube tester at real world operating voltages (250 volts in the case of the a2900), one tested tubes are also matched at those voltages. For power tubes we match based on EM first and then GM. For small signal tubes we match based on GM then EM.
Please be aware that vintage vacuum tubes are antiques and carry no guarantee or warranty. We provide a sheet explaining what you purchased, your test results for your tubes, and if need be can provide photographs of the tube on the tube tester before we pack and ship them.