Hey guys, long time reader and bystander second time poster. Sorry if something like this has been asked already. So anyways my situation and question: I have a chance to buy an EBS Classic T-90 tube head second hand this week. The seller will arrange for a meetup where I can try it myself before making the decision. I know what I'm looking for in the amp and I understand the knobs (well duh, there's like three) pretty well, but the "presence" knob still kinda eludes me. I know it's boost only and it's a frequency between bass and treble so I'd assume it would act as sort of a (high)mid control. This however puzzles me, since AFAIK the bass and treble are boost AND cut so why's presence only boost? Also the website says that it's "power amp eq". What exactly does that mean? Thanks in advance guise, I'd be beyond grateful if someone can correct/confirm/elaborate on my assumptions here. Keep playing! Bass.