Package of 2. The JJ Electronic 12AT7 / ECC81 is a good choice for phase inverters, reverb drivers, and general preamp use. This tube offers low noise, low microphonics, and warm smooth tones at a great price. Like all JJ tubes, it has a rugged construction that doesn't compromise the sound of your amp. The JJ 12AT7 is a solid replacement for any 12AT7, ECC81, or 6201 tube. It can also be used to replace 12AX7 tubes in position 1 to reduce gain.