Not really interested in doing any mods to the SP-9 right now. I just thought that if they were plug in compatible it might be fun to grab a pair of 6H30s and swap them in for the 6dj8s and see how it sounded. Current production 6H30s would only run me about $60 for a pair and if I didn't like them I could always swap them back.
Not looking to get into a big project,just a little one afternoon nervosa fix.
But if I can't swap them without modding the amp it will involve much more effort than I was looking to put into this.