I'm rebuilding a set of Dyna Mk IIs, the original ones with the square circuit board. Purchased a set of Poseidon boards as well as a pair of SDS cap boards.
Question 1: Any thoughts about running KT-77s in this rig? I would assume that the bias would be set to 50ma / 500 mv per side? Any other mods?
Question 2: WHat about using a EC99 or 12BH7 in place of the 12AU7. On Ned's Triode Mk III board, both are listed as options (with associated circuit changes)
Question 3: See a post where someone used a 5751 in place of the 12AX7. any changes required to make that work (slightly less gain as I recall)
Question 4: Surge limiters, what size would be recommended for this amp with a 3.2A fuse?
Using Hexfeds (fast recovery) diodes in both bias and HV, my bias circuit has a 100 mfd and (2) 50 mfd caps, the latter bypassed with 0.1 and a 0.02 mylars. Using a 25k 2 watt pot to give me flexibility with El34s, 6550s or KT88/90s.
Thanks