The very low input impedance of the 14B3 (7.5K unbalanced, 5K balanced) makes it unsuitable for use with the majority of tube preamps, as well as with passive preamps such as the Lightspeed. A tube preamp that comes to mind that would have no problem driving those impedances is the Atma-Sphere MP3. A dealer presently has a new MP3 listed for sale here for $5K, without the optional built-in phono stage.
Good luck. Regards,
-- Al
Good luck. Regards,
-- Al