I'm looking for a fairly cheap quad of 6l6's to try out in my trem-o-verb.. I bought it with EL34's and its time to try out something new. I can get either the Ruby 6L6GC STR, Svetlana 6L6, or EH 6L6's for around $50 a quad.. have you guys tried out any of these? Which do you think would be best for heavy music? Thanks!