"John Byrns" wrote in message
...
In article
,
Patrick Turner wrote:
In RDH4, P344, there is a 30W beam tetrode amp with 807 with SE
pentode input, pentode concertina.
Page 344 has the triode Williamson with 807. P353 is interesting
though, positive and negative FB loops are used. This is PURE
QUIRKINESS for those who must have quirks in their amplifier
collection. I have never seen any commercial design with PFB and NFB -
too hard to get right. But most amps do have quite a few quarks
lurking about.
Look here for a common combined PFB & NFB circuit.
http://www.triodeel.com/dynast35.gif
6.3VAC on the 6BQ5 (common) cathodes????
Gio
--
Regards,
John Byrns
Surf my web pages at, http://fmamradios.com/