The 12AY7/6072 and 5751 tubes have lower gain levels compared to a 12AX7. The 12AY7 and 5751 is directly compatible with any 12AX7 equipped amplifier. These tubes are nice if you are looking to have a less gain in the preamp. If you are looking for more clean headroom, then these tubes are your answer. These tubes sound great when installed in the V1 and phase inverter positions.