JJ ECC83s / 12AX7 Preamp Vacuum Tube
These tubes are immediately discernible from other 12AX7. They have a construction that is similar to a frame-grid tube - similar to the Telefunken ECC803s. This construction makes them very rugged and reliable. This is one of the best new 12AX7 for any guitar amp. It is very musical - rich with great harmonics. An excellent tube in all Marshall amps in the three preamp positions.