The older S8000's used 12AX7 tubes in the low level stages, and the newer
ones use the 6EU7. The schematics are somewhat different.
I have the older model, bought from a HI-FI store in Austin, Texas back in
1977 for $15.00 as-is not working. Since then I have gone through it twice,
although some of the original tubes remain. I put in a new set of Sylvania
7868's in 1981, and they remain there to this day. The Sherwood logs about
10 hours a week minimum use since it is connected to the home entertainment
system whick includes the Nintendo Wii where we stream Netflix almost daily.
Back in 2002 it finally crapped out after limping for a while. All the
wiring to the power transformer started falling off. I almost junked it.
http://pages.prodigy.net/jcandela/Sh...0/Transformer/
After redoing that wiring, along with the output transformers as well
(primary only), I got a wild hair to re-cap, and then start a crazy crusade
to play with SS FET regulators:
http://pages.prodigy.net/jcandela/Sh...8000_Mods2.htm
All those regulators fit on a 2" x 2" perf board with a small processor
heatsink with a tiny fan. Been working fine for the last 7 years, other than
losing a receiver IF tube filament. The sound is awsome with really enhanced
bass due to the stiffer plate and screen supplies to the output tubes.
I don't necessarily reccomend anyone do these mods unless you have a well
equipped bench, and a lot of understanding of how things work. It is tough
to make solid state requlators short circuit proof. I tried, but was too
chicken to test! :-)
Jim in Texas