GAIN (G) = pre-amp distortion (how clean/dirty the tone is) which is different to valve saturation.
VOLUME (V)= normal Volume, no real effect on tube saturation, setting can be saved
MASTER VOLUME (MV)= overall volume & tube saturation level, setting can't be saved. The higher the MV is set, the more 'tube saturation' (TS). TS is different to G - it gives the overall tone more vibrancy, feel & response. On high gain amp models in particular, overdoing the MV can make tone muddier - between 1-3pm is usually best.
POWER-SELECTOR (PS) = attenuator.
By turning PS down, it allows the MV to be raised giving more tube saturation, whilst keeping overall volume levels down. This is a similar principle to using a 'hot plate' attenuator with an all-valve amp whereby you can crank up the amp volume & thus increase the load on the the tubes for more tube saturation, but with the attenuator reducing audible output volume -think of an AC30 for example, where there is no MV, and the only way you can crank the valves & make them work hotter/harder is by raising the amp to gig volumes - won't go down with the neighbours at home!
The shared problem with the PS on the V'x and a hot-plate attenuator is that they both 'suck tone' at lower volumes ie it's a compromise. So, playing at 1w is fine for late night practice, but tone quality is severely reduced. Hence why many prefer a compromise whereby the PS & MV are raised, but with the V turned down.
Turning down V too much means that less effects signal gets through eg reverb etc, so it's all about getting an acceptable tone at different volumes. So, just like an all-valve amp, the louder you can set everything overall, the better is your tone.
On my AD120VTH, at home I usually have the PS at 2x15w (sometimes 2x30w), MV at 1-3pm. For gigs, the PS is either at 2x30w or 2x60w depending on venue.
The PS attenuator on the chromes is variable, as opposed to the 4 set positions in the blues. But the attenuator is not as good quality and will sap tone more at lower settings. For this reason, folk have found that although in theory they can get more tube saturation at quieter volumes by raising the MV and lowering the PS, overall tone improves significantly with PS raised and MV/V lowered.
It's all about learning how the amp works & finding the right balance for you.
You may also find this section in the FAQ helpful: -
http://www.valvetronix.net/forum/strugg ... vt674.html
Rich
