I have read some threads here, and understand about the low-pass filter, and Q switches and variable Q control.
 
But what does a quick tone switch do exactly? (as found on EUROPA & ROGUE)
 
And the ORION/EPIC/EXCEL 'Bass & treble controls' - are those roll-off or boost & cut? (and do they have dip-switchable treble frequencies like EMG's BT controls?)
 
(sorry if this is painfully obvious, but I couldnt find this info anywhere on the website)

The quick tone switches on the Rogue & Europa are two 3-position boost/cut switches. One for Bass, the other for Treble.  The 'Q' switch has two positions. The Excel has Bass & Treble roll on/off controls.
 
Rami

ahh..  
 
so the quick tone switches apply an additional +/- 3dB to whatever each EQ is already set at? (and middle position is 'flat'?)  or do they overide what each EQ is currently set at, to provide 2 extra presets??  
( the third preset being whatever the knob is set to??) ... (that would seem the handiest to me)
 
and excel type controls are like +/- 10dB shelving EQ, centered at say 80Hz & 5Khz?

Something like that!  
 
The middle position is flat for the switches and the knobs.  As for what they actually add or cut, I leave that to Mica!
 
Rami

The quick tone change switches are independent of the filter  and offer  +6dB / flat / -6dB.  So in the center position, they're invisible The effect of these switches is between the pan/balance and filter. These are found on the Europa, Rogue and originally on the Distillate model.
 
The bass and treble controls (like on and Excel or Orion bass) are asymmetrical, +6dB and -15dB centered around 100Hz and 5KHz.