Morgan,
Looking at the tube compliment of your amps I see 274Bs are acceptable. Buy a simple pair of Shuguang 274B rectis online--you can get them for $10 each if you shop around, and see if that brings you exactly what you're looking for. I'm blown away by what that cheap recti is doing in my AN211 as is a buddy of mine with them in his Tubeguru F2a monoblocks.
Looking at the tube compliment of your amps I see 274Bs are acceptable. Buy a simple pair of Shuguang 274B rectis online--you can get them for $10 each if you shop around, and see if that brings you exactly what you're looking for. I'm blown away by what that cheap recti is doing in my AN211 as is a buddy of mine with them in his Tubeguru F2a monoblocks.