9 pin miniature preamp tube (Amplification Factor = 100). This Russian tube is full bodied and well balanced. It has a high gain with a very smooth presentation. In overdrive, it is not quite as defined as the 12AX7-S-JJ, but it offers more crunchy fizz.
For more information about our 12AX7 tubes, see our tech corner article on 12AX7s.