16 Ohms tap with 8 Ohms speaker

surprise! surprise! I connect my JBL LE14C ( 8ohms crossover) to 16 Ohms tap of Dynaco ST-35 driving by my prototype LDR Jumpan Pre. Connect the speaker to 16 Ohms tap sounds much better than connect to the amp 8 Ohms tap, deeper bass, more liquid midrange and very detailed treble. I know the mismatch impedence will not give maximum power transfer, but who cares if it sounds good.. quality is more important than quantity..

Well, quite normal lah. High imp output to lower imp speaker will offer more resolve than matched tapping. Moreover if you're happy or like it, its entirely up to your liking for long term.
Its the same phenomenon for LS3/5a owners who could prefer 16ohm tap rather then 8ohm tap to their 11ohm speakers.

In fact the impedance of the speaker change at difference frequency. a 8ohm speaker will not give 8ohm at all frequency.

It is coincidencely the portion it drive well using 16ohm match your taste.