It sounds identical to the ecc83 CZ. It gives some serious weight to your sound, but depending on the amp, it may bring mudness. The more driven it gets, it sounds better, and i'd recommended this tube only for high gain applications on the second or third stages. Surely not intended as a phase inverter. It operates quietly and free of trouble. Unless you wanna be sure about it's accurate operation, there is no need to spend the extra money vs the ecc83 CZ. Again, i've compared both of them and they work identical.