What set of tubes do u guys recommend for my MPX3 SLAM to get a very "tubey" sound -- looking for lush, liquid and euphoric -- and a very solid state sound?
For me, I like having a choice of strong opposites, like having a pair of Grados and a pair of Senns rather than finding something in-between.
A Raytheon 5687 driving Sylvania VT-231's is ridiculously tubey and lush. It synergizes wonderfully with my R10's midrange and boosts bass response as well (I have one of the more bass-endowed R10s to start with). Also sounds great with the JVC-DX1000 and L3000; really synergizes with the already lush nature of these headphones. The drawback is that the bass can distort somewhat at high volume levels, but for midrange it's incredible. Also doesn't have the slam of other tube combos. Not so good with the Qualia.
A Tung-sol roundplate VT231 or KenRad VT231 driving TungSol D-getter 5687's. This is a much tighter, snappier sound with a bit of a smaller soundstage than the above combo. A bit drier in the midrange. You could say it's a bit more like really good solid state. This works best with the Qualias, also really good with L3000 (this combo's slam with the L3000's killer bass is awesome).
Please note my ideas on synergy - I don't like to counter the strength of one component with the opposite attributes in another component; I like to pick components with similar attributes so that they enhance each other's strengths. In a nutshell I think synergy should focus on enhancing strengths rather than countering weaknesses, hence my tube choices for my various phone above.
I think my friend purk's upgraded SDS uses different types of tubes that combine the best attributes of both tube combos I've listed above, but I haven't spent as much time with that amp as I'd like I'll have to get my SDS upgraded before I can try those tubes. Man, it's so difficult to keep up with the current state-of-the-art tube combos for Singlepower amps, I already feel way behind the times