Mcpherson
All tube power amps needs to have the tubed biased, Some amps have an auto bias circuit which does this for you, other you have to adjust the bias manually through a voltmeter or in the case of the Thor, the meters are built in so each tube can be matched to the manufactures specs for the amp.
All tube power amps needs to have the tubed biased, Some amps have an auto bias circuit which does this for you, other you have to adjust the bias manually through a voltmeter or in the case of the Thor, the meters are built in so each tube can be matched to the manufactures specs for the amp.