I just bought a Hafler triple giant preamp(the Bogner model). It has 7 tubes in it and it came with all Fender 12ax7 tubes in it. On the 3rd chanel, the solo overdrive channel, it seems really buzzy. I'm wondering if I changed out all the tubes would the noise level reduce a little(switched to mesa or ruby or even GT.)? Fender tubes arent really designed for high gain are they?? So would switching give me a little more gain too?