SovteK 12ax7 LPS
They have very large ribbed plates and great sound reproduction. They are very smooth and well balanced in terms of bass, mids and treble response. The large plates make them more prone to microphonics and in combo amps, and high gain preamp stages. It is still the best thing Sovtek has produced in a 12AX7, with very good gain and low noise. I would advise against using them in compact high-powered combo amps where they will be subjected to lots of vibration. An excellant choice for hi-fi pre-amps, mic pres, audio processors etc.