Jiceman, FWIW in my SP10 I used 6h23s (low noise/rugged) in the critical positions but I found I can put 'colored' tubes in the cathode follower positions (which do not add any gain and are less demanding on noise issues). I long ago gave up trying to get tone from the critical positions.
The cathode follower tube/circuit provides no gain but affects the output so that you can drive long runs of IC's. Google it - I'm sure there are many thorough explanations there.
The cathode follower tube/circuit provides no gain but affects the output so that you can drive long runs of IC's. Google it - I'm sure there are many thorough explanations there.