Groove Tubes

Common to higher powered tube amps, like the later Fender Super Reverb amps and the Vox AC30 (or Matchless copies). It is a higher powered tube type rectifier. May be used to replace a 5U4 or 5Y3 and will give a faster more dynamic tonal result. This rectifier has a rise time from 300-400 volts that is about 1/2 that of a 5U4 so they are very nice in amps such as the Mesa Rectifier series which use the 5U4 if you want a feel and response that is tighter than the stock rectifiers yet retain the feel and compression character of a vacuum rectifier over the solid state setting.