I recently scored a mint "closet classic" 1976 DR103. Its loaded with a quad of Mullards that in all likelihood have little wear on them judging from the condition of the amp. Obviously the amp sounds great with the Mullards, but at the end of the day I'd rather save them for recording when it counts. I feel like a glutton just using them for practice/jamming in my basement! lol. I intend to use this amp primarily for bass and was wondering if you guys had any bass specific tube suggestions for a DR103. My natural inclination was to just grab a quad of winged Cs, but then I started reading about other options such as JJ KT77s, Gold Lion KT77s, EH 6CA7s, etc. What do you guys think?