The power transformer in the Fet Valve 400R is nearly 600VA capability with three sets of outputs.
Primary: 2*117V 50/60Hz 590VA
Secondary: 119.2V 4.5A 15.1V 1.12A 230V 0.12A
Overall dimensions: Diam: 5.5”
(approx given) Height: 3.2”
Weight: 13 lbs
There are three sets of secondary windings.
High voltage high current for output section.
High voltage low current for tube high voltage section.
Low voltage high current for tube heaters.
The 400R runs class A up to about 20W/channel.
Rated power is 225 W/Channel into 8 ohms, more into 4 ohms.