Okay, being the gear freak that I am, and having quite the Trace Elliot tube gear fetish, I have recently picked up a VA400 and VR350, and I have a Hexa on the way (already have a Quatra Valve, Twin Valve Combo, and a V-8). Yes, I know, out of control. But, I need some help from you guys/gals in the know. The VA400, VR350 and Hexa Valve all employ what appears to be a similar tube output section. They all have six 6550/KT-88 tubes, and visually, there are a lot of similarities. But, not being the tube amp guru (and not being able to find a lot of information on-line), I was wondering if anyone had any information to share regarding the differences between these three. I do have the schematic for the VA400 (which I found on British Audio Service's website), but can't find one for the other two (and in truth, while I can somewhat follow the schematic, being a "layman" with regard to tube amps, it does not answer all of my questions). Any insight? Also, the VA400 and VR350 have a low, mid, and high setting for output power. Any ideas as to what exactly these controls do, and what the relative output might be at the various settings? I know that the V-8 allows you to run one or both banks of four output tubes (for 4 or 8 tubes), and I am wondering if this sets it for 2, 4, or 6 tubes? Any tips or references on biasing? The VR350 and VA400 have bias adjustments (I don't believe the Hexa will, as my Quatra does not). Finally, I have a question about the inputs on the VA400. It has a "valve preamp" input as well as active and passive inputs on the GP12 preamp section. My suspicion is that the valve preamp sends the signal to the driver tubes (like using the "instrument input" on the VR350), but yet the Gain and Master controls still have an impact on the overall volume (though the EQ doesn't seem to be in the signal chain at this point). So, my first question is what exactly is in the signal path when I plug into the "valve preamp" input. My second question is what exactly is in the signal chain when I plug into the "green" inputs on the GP12 portion of the VA400? From the schematic, it looks like I go through one half of the V1 preamp tube when I plug into the GP12 inputs, but I go through both sides of V1 when I use the valve input. And of course, any general comments/observations/comparisons about any or all of these amps would be appreciated. Thanks! Tom.