"Peter Wieck" wrote in message
oups.com...
I did a little bit of hunting about, based on some suggestions received
here and elsewhere. At this point, after looking hard at the Fisher
500B schematic, the B+ available out of the power transformer I have,
the load headroom I have if I reduce the number of tubes, and other
factors, I am leaning towards 5881 PP output tubes driven from a single
12AX7. I will investigate some further on whether the output
transformers are appropriate for this configuration, but on first
blush, it looks OK and has the virtue of simplicity. I ought to be able
to get about 20 very clean watts or so. Nothing that will set the world
on fire (at least one certainly hopes not), but could be very pleasant.
This also fits my existing tube inventory nicely. Parsimonious, not
cheap.
So, solid-state rectification, significant filtration, and as few parts
and pieces as possible thereafter.
Thoughts?
Thanks in advance.
Next, start sketching actual circuits...
Peter Wieck
Wyncote, PA
Peter,
Check out this schematic of an Eico 87courtesy of Triode Electronics. (1)
12AX7 and (2) 12AU7's (in place of the 6SN7's in the schematic) instead of
(2) 12AX7's. For that you get a pretty decent LTP phase splitter which is a
good choice, especially if you triode connect the 5881's.
http://www.triodeel.com/eicohf87.gif
Best Regards,
Mark