|Author:||John Hannon (registered user: 376 posts )|
|Date:||Mon, Jun 25th, 2012 @ 16:03 ( . )|
Yeah, I guess "low gain" is a relative term here. The 5654 is a crazy-sensitive tube, with a transconductance something like 3X that of a 6SJ7. That's why I've got a 250K volume pot instead of the usual 500K. There a chart on the GE datasheet showing various examples of a "class A resistance-coupled amplifier" wherein the gain ranges from 170 to 310! [link]
The low load resistance + CF bootstrap is my attempt to keep the load line somewhere near the knee while still getting kind of a lot of gain--while not attempting the silly amounts of gain that traditional designs wring out of a pentode. Is that what's really happening? Dunno! ;^] That's what I was thinking though. It sounds good, and so far no microphonics, so I must be doing something right!
--* New prototype amp!
6/26/2012 @ 02:59--jazbo8
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