Let me start off by saying that I love the sound of a good all tube rig. Back when I was playing full time in the 70's and 80's, I had an early 70's "blue line" Ampeg SVT/Sunn 2x15 loaded w/JBL K140s rig that was the best sound I ever had … even to this day (and I have some pretty darn good gear now). However, I think that the warmth and response of a good all tube rig is more important to the player than to the audience. I don't think that all that many bass players could pick out an all tube from a hybrid from a completely solid state rig in a blindfold test with it mixed in with a band in a big room and that considerably fewer non musicians could tell the difference under the same scenario. Another issue is that as soon as you have sound reinforcement in the equation, the all tube nature of your head is somewhat compromised from an audience perspective. Short of bleed from the vocal microphones picking up some of your stage sound, the audience is going to mostly hear a DI off the amp, a DI off the bass or your cabinet mic'd. In all three scenarios, there's going to be a whole lotta solid state between your stage sound and what the audience ultimately hears … solid state mixing boards, solid state EQs, solid state compressors, solid state crossovers, solid state poweramps, etc, etc. In the case of the DI taken right off the bass, your all tube amp is practically out of the equation if the venue is large enough where the stage sound is not heard by the audience and unfortunately, in the case of SVT heads, their DIs are either too noisy or are _perceived_ by most sound men as too noisy where they will almost always take the DI right off the bass with that amp. Back in the day when I had that killer blue line SVT, the preamp out was WAY too noisy and I used a Countryman Type 85 direct box right off the bass. In recent decades, I've probably done ten backline provided gigs where the supplied rig was a modern SVT variant with its own DI and the sound men _still_ chose to use an external direct box and take it right off the bass. More often than not these days, when I have the opportunity to do a sound reinforced gig, I'll bring my Ampeg SVP CL preamp loaded rack rig because it has enough of the essence of the classic SVT sound, but with a quiet DI that is actually usable by finicky (and noise averse) live sound engineers. And speaking of sound engineers, _they_ are actually going to be your "critical success factor" for sounding good to the audience. The first time I played the Columbia Pike Blues Festival, they supplied a GK 800RB/Hartke aluminum cone 4x10 rig, but took a DI right off the bass using a very cheap Horizon direct box that I'd seen in stores for less than 20 bucks. A cable access company did a pro filming job of the show with the sound taken right off the mixing board going into the recording. I got the business card of the guy filming it after the show and made arrangements to get a VHS HI-FI dub of our show from him. Anyway, the DI right off the bass into that cheap direct box ended up being the best tone I've ever gotten … clearly because the sound man really knew what he was doing. On the other end of the spectrum, I once saw Chris Issak at a "shed" type venue here in VA and his bass player played a pre-CBS Precision through a pair of blond Fender Showman heads with matching "tone ring" 1x15 cabs (undoubtedly) loaded with JBL D140 speakers … basically a "voice of God" setup. The rig was mic'd and everything was in place for the bass to sound really good. Instead, it sounded very muddy. You couldn't make out anything that he was doing. I wouldn't stake my life on it, but chances are the sound engineer didn't know what he was doing and all the advantages of that great rig were negated.
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