GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Audio Discussions
In the Thread: How to get a LOT of SET power.

Post Subject: 2 stagePosted by N-set on: 4/17/2011

Paul, I'm not rushing to the breadboard. I'm trying to visualize if Romy's constraints
can be satisfied. I have to gather more data on GU81 to think of doing anything.
How linear it is?? Perhaps this tube is an audio no-go as you've mentioned?

Going to 3 stage would defy the whole GU81 exercise. If alowing the 3rd stage I'd go with 304tl A1
in the first place or 833A A2. Both seem to have a +/- good reputation in audio.
And reputation is what unfortunately I have at my disposal at this stage. Same applies to 6E5P.
I agree that 6E5P seems to give just right enough gain to approach 0Vbias
(2Vrms x 32=90Vmax), without margin,
but anyway I'd parallel
the drivers than add one more stage. I've somehow bought the Romy's sense of elegance
with 2 stages.

PS caps are seemingly not a big problem: find the Nichicon part number, google it,
put your spam-friendly email in the pages which locate parts for you, in the next 2 days you'll
receive 40 offers from Asia. Some seemingly serious, but I haven't tried so far.

I'm not in love with transformers, but not affraid of them either (so far...)
Again driven by the sense of elegance rather,
I'm attracted by a simple design with few stages and one big tube. I of course can be
very wrong, as I said at ULF small dissincronizations of paralled tubes should not
matter (no time-domain smearing). Transformer will have to handle the power anyway,
so it will be big, but the compromises with HF are absent, as have already been mentioned 1000 times.

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