While I can't comment on the newer B&K ST 140, I'm in full agreement with Infinitebaffle on the rest of his post. I'd like to add that the B&K has a rather low-input impedance that might challange most tube pre-amps that usuaully have high out-put impedances. I can't remember the what impedance the Adcom presents.
Adcom 545 vs. B&K st-140
Looking for a bargain amp to drive 4 ohm speakers and mate with tube pre....any thoughts?