John, pardon the ignorance. . . I do not know what SMPS may be.
On the subject of tube preamps running hot. . . it depends what's in the power supply. . . my Audio Research has both a 6550C and a 6H30 in the power supply and runs quite hot, particularly in summertime.
On the subject of tube preamps running hot. . . it depends what's in the power supply. . . my Audio Research has both a 6550C and a 6H30 in the power supply and runs quite hot, particularly in summertime.

