Mullard 12AT7 / ECC81 - Current production Russian re-issue. These tubes are quiet, they sound great, and are dependable... giving them Uncle Kevvy's seal of approval. A great choice for any 12AT7/ECC81 circuit.
This tube tested extremely low in noise and microphonics across the board, so we do not have any Driver Grade.
Platinum grade - The best of the best. Lowest noise and microphony with the tightest triode balance we have available. This is typically 10% or tighter, but may be higher depending on available stock.
Gold grade - Low noise and microphonics with a triode balance typically between 15% and 20%, but may be higher depending on available stock.
Driver/Buffer grade - Lowest noise but not the lowest in microphony. Triode balance will be similar to Gold grade.
This grade is only suitable for use in the driver stage of an amplifier, or the output/buffer stage of a DAC or CD Player.
If you have a preamp or phonostage, you need at least Gold grade.