That's why you didn't usually see it in higher powered amps. It is less efficient than fixed (grid) bias so the wattage is a little less. There are relatively few causes of output tube bias problems. Between these two could be a flaw in the amplifier or could be one of the very rare amplifiers that use a combination of cathode and fixed bias. If it is 50 ohms or more, you have an amplifier that is cathode biased. That's one of the reasons I like my JAZ 20/40. If this is under 10 ohms, you have a fixed bias amp. Cathode biasing adds some compression so it behaves a little like an amp with a tube rectifier. So to answer your main question, I can't tell any difference in tone. Also, the claimed wattage for that amp would require that type of bias. The Humbucker Music ad for the Victorilux doesn't use the term 'fixed cathode bias' either but it does say that the amp was derived from a 'AB765' circuit so that would be fixed bias. It has amps/cabs as well as the option to edit some of the components of an amp to change some of the character of it. I've seen a combination of these two used but it didn't work very well. Bias AMP is strictly an amp modelling VST and is catered around that. The other is grid bias which uses a resistor, either fixed or variable, to set a voltage to the grid. One is cathode bias, which uses Ohm's Law to vary the bias of the tube at the cathode. As far as I know there are only 2 ways to bias a tube. Out of curiosity I looked at the Victoria Amps website and I can't find where it says 'fixed cathode bias' anywhere.

Variable bias vs fixed bias guitar amp