I owned the Mk-I. I liked it.
Traded to the Mk-III. I liked it too.
The Mk-I has one bias trim screw per side.
The Mk-III has two bias trim screws per side and 6H30 input tubes.
Two screws per side allows for finer biasing.
I use solid state amps now.
I think solid state does a better job in a power amp application.
Tubes are still the way to go in a pre-amp, however.
Traded to the Mk-III. I liked it too.
The Mk-I has one bias trim screw per side.
The Mk-III has two bias trim screws per side and 6H30 input tubes.
Two screws per side allows for finer biasing.
I use solid state amps now.
I think solid state does a better job in a power amp application.
Tubes are still the way to go in a pre-amp, however.