Spectron musician VS. Pass Labs Amp

Because when you wrote
(( My preamps are BAT 51SE and NAT Audio Symmetrical, both are tube pre))
loading down a tube pre is going to hurt your perception to everything not only bass.
Cheers Johnnyr

(((My preamps are BAT 51SE and NAT Audio Symmetrical, both are tube pre,)))
((I know that my Spectrons are extremely superior to any other amps I have owned playing my speakers.))
All you proved is that you loaded down your tube preamps
into a 15K input imp causing them to play sluggish bass into the Pass further causing a distorted non desirable outcome
kind of like shooting the messenger.
Cheers Johnnyr