The tone knob on a guitar is almost always a filter, unless it is an active circuit, in which case it may be a cut/boost.
Amp controls are also generally filters, with frequency centers, as opposed to high-pass/low-pass. I may not have the terminology exactly right, but, in general, you're looking at cut-only controls, hence "everything on ten" is the amp on max. Graphic eq's, while rare, will tend to be cut/boost, and narrower.
Whether an amp's controls are pre-gain or post gain has a tremendous effect on the result of knob twiddling the dirty channel/setting, and varys on an amp to amp basis. Pre gain eq changes the character of the sound, while having a lesser effect on the final harmonic content. Post gain eq is the opposite, having a marked effect on the bassiness/treblyness/middiness of the sound, while not really effecting the basic tone as much.
If that makes any sense.
For instance, cutting pre-eq bass will make a palm-muted E string sound less saturated, more textural, less thumpy, but not really less bassy. Increasing mids or highs would make those frequencies thicker, but not really more prominent in the tonal balance.
Post eq behaves like you would probably expect eq would behave, removing or adding energy at varying frequency centers, similar to if you eq-ed it after recording the sound. Any power tube saturation would behave as if the eq were pre-gain (since the eq is, in fact, prior to the power section).
No more posts for me until the coffee starts kicking in.
