Perhaps I'm just hearing what I want to, but my 900 seems quicker and more "Shuttle-like", when I cut the gain back a bit, leave the boost button out, and open up the master volume some more.
This is with a pair of active basses that have pretty hot output.
+1 Given the 'real tube' preamp design (versus what some call a 'marketing tube' like in the Eden heads, and many other hybrid executions), I treat the gain control on the Streamliner like another tone control. Even the interaction between the gain and volume control can change the nature of the response of the amp and the tone and 'warmth'. Set at very low levels, the 'tube complexity' you get when pushing an input stage tube disappears, making the amp 'feel' much more like most other amps. When you push that gain control a bit, just like with the Walkabout head (another 'real' tube preamp), the magic happens!
IMO.... the technical reasons for this are over my head, but the tube execution of the Streamliner is a totally different thing from most other hybrids (even the Shuttle amps). It is more in line with some of the Mesa heads, which really do vibe an 'all tube' signal chain.
