Hi all, how critical are the (4) 12ax7s to the tone of the Hagerman? I'm assuming the 12au7s are doing the heavy lifting tone wise but maybe I'm wrong? If I wanted to open up the sound, make it more transparent with more pronounced highs can I get any recommendations? I'm currently running '60s Raytheon 12au7s and a mix of NOS RCA/Teles in the 12ax7 slots (also do these need to be matched?) Thanks!