In addition to the 6V6 amps that did not go Ultralinear, the Vibrolux Reverb is the only 6L6 Fender Guitar amp that did not get that change to UL. The Vibrolux Reverb also never got the master volume treatment. These two aspects and their lower B+ differentiate the VR from all other Fender 6L6 reverb amp’s. They are my favorite BF/SF amp. Ultra linear.....don’t look now but there is more than one well-respected, high-dollar boutique amp that run an Ultralinear output. In a UL Fender, if you don’t like it, it can be changed.