There’s a lot of BS in the adverts C core transformers are far better like the world class Lundahl you see in Ayon for example , Torroid are better in solid state gear
look at-any top quality tube amp C cores only .
and the auto bias system nothing to tag about bunches of resistors in the auto bias. Ayon night and day more reliable and high tech ,it doesnot average all the tubes like in auto bias , the Ayon has a micro processor and monitors each tube
for optimum Ma voltage , and when a tube goes the amp will go into standby and a led will come on , you reset the bias and the processor readjusts it .
far better and a machined aluminum case for vibration ,not cheap sheet metal.