ECC83S/12AX7 JJ Electronic Preamp Tube, the best value valve. ECC83S/12AX7 JJ Electronic Preamp Tube The JJ Electronic 12AX7 / ECC83 has quickly become a modern classic in preamp tubes. Its rugged design and rich harmonics make this tube an obvious choice for musicians who need a reliable and high quality tube at a reasonable price. The balanced tone of the JJ 12AX7 works well in any amp. This versatile tube sounds excellent in clean amps offering an amazing dynamic response while also proving itself in high gain amps with its low noise and noticeably less microphonic issues than other tubes. The warm highs and transparent lows make it a great choice for any position in a tube amp. The JJ 12AX7 is the go-to tube of many amp builders and touring musicians.