VTL Tetrode/Triode

Zaikesman: thanks for the above, informative post. I'll try that, as this will be a more "fair" comparison. But in any case, I suspect I will continue needing to run with full banks in tetrode, unless I upgrade to a MB-750, or to the Siegfried (yeah, right!).

I also agree with you that being able to change the sound at the flick of the switch is perhaps "unsettling." But with other amps which don't have a switch like that, the problem just isn't that apparent, but present nonetheless.

Any amp, whether tube or solid state, has a certain sonic signature, let's not kid ourselves. So the VTL amps have two sonic signatures, that's all.

Exactly right. I got over the 'unsettling'. The 'useful' remains.

What is the difference between the on/off rocker switch and the on/off rotary switch used on VTL amps? Which is the newer design? Thanks

If I'm not mistaken, the knob is only used on the double-decker Reference amps, the rocker on the single-deck Signature models and below. I would assume that the rotary switch is heavier duty rated for the higher power; maybe it's a 20 amp part. But I don't know this, and I suppose it could also just be a cosmetic difference. I don't think I recall them always using it on those models, but that observation doesn't prove anything, as they might have recently upgraded the part, just as they've upgraded their fusing in recent years. Call and ask. BTW, VTL has recently upgraded the input stage on the Signature monoblocks to a differential design as in the Ref's, but haven't seemed to advertise the change or its benefits. (Unfortunately, for owners of previous-gen Sig's like me, there is no upgrade retrofit possible.)

I'm not sure whether or not the upgrade of the input stage to the differential design has any sonic benefits IF one's cabling is all unbalanced, single-ended, with conventional RCA connectors. But it does make a difference if you're running balanced components with XLR connectors (or so I've been told).

Anyway, with my setup, which is unbalanced, it probably doesn't matter. (And in my system, unbalanced actually sounds better, there is more of a texture to the music, whereas balanced conveys a more bland, "bleached-out," sound. I gleaned this from having compared Transparent super unbalanced to Transparent ultra balanced - - but this was, of course, with the old input stage).