The Var EQ/Therm sets in your interstage so you don't over EQ your first Amp and yes you can ajust your Amplitude. It's usally set wide open -3 db. They also come in different EQ Varible sizes it depends on your system specs 9 or 12 BD. I hope this helps.
This is CABL.com posting #332091. Tiny Link: cabl.co/mbyyt