Re-housed 1st generation Sunn Model T from 1973. This is one of the loudest guitar amps ever. It uses an ultralinear output transformer because the output section is modeled after a Dynaco Mark III, meaning that the screen grid supply is fed through the output transformer as well as the B+ voltage -- the output transformer is a dual primary, one for the B+ and the other for the screen grid. Because the screen grid supply and the B+ come from the same power supply node their voltage fluctuates up and down under load together. This connection provides some feedback between the anode and screen grid and has been found to to act in a way that is between pure pentode mode and pure triode mode, with lower distortion than either.
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