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Triode or UL for SSE?

That is a question with a different answer depending mostly on the choice of music, speaker system, room size, and expected listening level.

For those who prefer simple music like a female singer with minimal accompaniment, say Norah Jones, Enya and the like, played at medium volume through relatively efficient speakers, the choice is usually an EL34 in triode with no feedback.

Want to play techno or crank some Pink Floyd at levels where the peaks touch clipping. Got big speakers and big OPT's, then run KT88's or 6550s in UL with the CFB enabled.

For anything in between these extremes, its harder to guess what you want without more information.

A few builders including myself have experimented with pentode operation, but it buys little over UL and requires more feedback to clean up the bass that the SSE was designed for without hacking up the circuit a bit.
 
I'll install switches for the CFB and UL mode. My SSE was connected in triode mode with no feedback. Reminded me of my very first tube amp i bought from Decware, a little two watt job that sounded really good, but didn't get loud enough to satisfy me when I had my beer muffs on.

Just for fun, I connected the OPTs UL with CFB. I like it a lot and it is louder.
 
My SSE have the following setup:
No feedback
Triode connected 6550
97 dB speakers
Playing blues, rock and jazz mostly. Metal missed some guts tough.

Have passed by:
Triode and UL with and without feedback EL34 and 6550, no switch just reconnect. And have preferred the actual setup.

Transformers: Transcendar 15 W

Just for information. It's all about taste, but the amplifier sound very good.

Greetings
Roberto