Recommendations for 6888 triode operating point?
In the midst of my ongoing parts clean-out, I discovered a bunch of Sylvania 6888 dual-control pentodes. I was about to add them to a bulk sale on an auction site, when I re-read Steve Bench's article on triode-connected 6888s.
Wow-- these things are beautifully linear when triode-wired. I began thinking of a small SE amp, or even a White cathode-follower OTL headphone amp. My question is this: How do I determine the best plate voltage, plate current, and output transformer impedance (if any) for a non-standard application like this?
With an Rp of less than 1k, it looks like a 3.5K output transformer would probably be a good choice. But what if I dial back the current, run the voltage up to the limit, and use a 5K transformer? I realize it will put out less power, but will it likely sound better?
Is there a theoretical method to optimizing a single-ended amp design, or is it something, once you determine a normal range of parameters, that is strictly empirical?
Even better, is there someone who has built a triode-wired 6888 amp, and would like to share the results?