THD ELECTRONICS FLEXI 50
- 50W, head-unit only, class A/B five tube chassis, preamp: 3 X 12AX7 (or optional 12AT7, 12AU7, 12AY7, 12AZ7, 12DW7, 12BH7, ECC81, ECC82, and ECC83), power: 2 X EL34 (or optional 6L6, 6V6, 6CA7, 6550, 8417, KT66, KT77, KT88, KT90, KT100, a...