This tube was also used in some cinema amplifiers, but it is somewhat problematic because of g1 leakage current. Use lowish value resistors on g1.
Here's another schemo of another commercially made amp.
Here's another schemo of another commercially made amp.
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! tube 6R3S-1 has two sections....two first grids, common second, common cathode, two plates. You can try PP with 1 tube. /Cathode to ground, sec. grid with 240 ohm to +240V, first plate to upper shoulder to OT, that will have 2 time more Ra, second plate to down shoulder of OT/.
also Pete Millet has an excellent design for the 829s.
There's also another thread on this elsewhere in DIYA.
Bob
There's also another thread on this elsewhere in DIYA.
Bob
you can start with this diagram.
I think the 100R resistor is too low - the 829 likes a max of 200V
on its screen. you could play with this when you build it.
You'll need to find triode curves for this tube to determine amount of
drive needed. This tube can handle very high voltages (probably due
to it's separate plate access) and I recall it can have a very high voltage
swing so driving it should be less of a problem.
Then work backwards to calculate gain for the front-end 6SN7's.
I think also that the first and second triodes need adjusting. Try
lower RL for first stage and if it meets the load-line requirements
for gain for the 829 in triode mode, then convert the second stage to
cathode follower.
Just some thoughts. You'll need to check everything you see.
Bob
I think the 100R resistor is too low - the 829 likes a max of 200V
on its screen. you could play with this when you build it.
You'll need to find triode curves for this tube to determine amount of
drive needed. This tube can handle very high voltages (probably due
to it's separate plate access) and I recall it can have a very high voltage
swing so driving it should be less of a problem.
Then work backwards to calculate gain for the front-end 6SN7's.
I think also that the first and second triodes need adjusting. Try
lower RL for first stage and if it meets the load-line requirements
for gain for the 829 in triode mode, then convert the second stage to
cathode follower.
Just some thoughts. You'll need to check everything you see.
Bob
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