This rectifier may be used in amps such as the Matchless DC-30 series and similar amps when you want more compression, less attack, and to lower the voltages in these amps. This rectifier gives a nice feel to these amps with a much slower rise time than the 5AR4 or the 5U4, with a great feel. This rectifier will also let amps such as the Matchless distort at a lower volume to be used in smaller venues and record sweetly at lower settings