moto man. Did you find extra midrange coloration with the Ref 6? I preferred my MSB direct on trying both Ref6 and ref 6 se
Geez, Ref 6 is pretty uncolored and clean for a tube pre. 6H30 are generally the cleanest sounding tubes, and Ref 6 is an excellent implementation of them.
If you talk about solid state preamps, or direct-drive with DACs - they usually sound fairly sterile and dry to me. Not my kind of sound. Now if you insert a good SS pre / DAC volume control in front of a tube preamp, you will hear 99% the same sound as the tube pre alone. So yes they are generally very transparent and uncolored - but I don’t like the sound of them alone in most cases. You could take this as damning rebuke of tube preamps, but our systems & hearing mechanics are very complex, and I will choose the more enjoyable & engaging sound (for me) every time. Hearing & preferences clearly differ from audiophile to audiophile.