on the 6505, the presence knob... i find it very useless, it doesn't do anything from 0-8 and then anything past 8 its so top endy and almost MT-2 sounding, is anyone elses like that where its so trebly and terribly sounding? or is it just mine
I found that you kind of had to keep up the presence up at low volumes, to give it a bit more bite, and roll it off as you crank the amp.
remember that the treble knob is also responsible for the amount of high end. adjust that as well. i tend to keep my presence fairly low and adjust treble to taste.
i find it has a lot more of an effect when louder. when i slowly turn up my 5150, i can hear the sound kick in and its very muffled. then fuzzy high end comes in. then more of the body of the tone. then the bass comes in. then once you have it around 3 or above, your amount of prescence and resonance and mids starts to have a lot more to do with the tone than before.
The presence dial is a poweramp control, so it will be more effective at higher post levels.