Ok.... after the umpteenth time (trying to do the picture) lets see if you guys/gals think this beast will work right...its' a melding of different circuits...I don't have the sims to just plug it in & my take is many of you will know the curves of said tubes by heart by now...for me this is very new...I was trained on solid state...alot of this stuff seems like Smith charts....who can tell me what a Smith chart is ??
Here goes..
_______________________________Rick.........
Here goes..
_______________________________Rick.........
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1M is a way too high value for the grid leak, I think the datasheet says 33k or so and even with cathode bias I would keep it below 100k.
I would also choose something "beefier" than 6SN7 in the driver position, but OTOH it´s an UL output stage so it might be quite easy to drive.
I would also choose something "beefier" than 6SN7 in the driver position, but OTOH it´s an UL output stage so it might be quite easy to drive.
Once upon a time (very briefly) I could use a Smith chart. RF engineers use them for analysing complex (j) circuits at a single frequency.
And the prize goes to the fellow from the UK for correctly identifying the use of a Smith chart...I once could use the dang thing...very complex stuff, but now I'd have to learn it all over again..
On the grid as "Fuling" noted..yeah it seemed rather high, I thought the value might have something to do with the previous stage.
Should the coupling cap between stages be rated for the second stage voltage? EG 900V+????????
As I researched the 813 the consensus is that it is easily driven typically less so than a 300B. The notation was a third of the power to drive, opposed to the 300B.
_________________________________Rick..........
On the grid as "Fuling" noted..yeah it seemed rather high, I thought the value might have something to do with the previous stage.
Should the coupling cap between stages be rated for the second stage voltage? EG 900V+????????
As I researched the 813 the consensus is that it is easily driven typically less so than a 300B. The notation was a third of the power to drive, opposed to the 300B.
_________________________________Rick..........
I assume you're powering the output stage filament with DC? The supply is, of course, in series with the input signal, so would be pretty critical.
Yes the filament is DC, driven by a pair of TO3 transistors....I'll have to keep the voltage differential somewhat close so I don't have massive power dissipation & add even more heat.
The filaments for the 6SN7 will be driven by a LM317K ....any way you look at it I will have heatsinks everywhere dissipating heat.
The filaments for the 6SN7 will be driven by a LM317K ....any way you look at it I will have heatsinks everywhere dissipating heat.
Robert Willis has several SE designs, just Google "Robert Willis diy 813" Also the thread: "Transmitter tube amp" on this website has a good discussion of grid resistance requirements. I am not sure I understand it yet. I have a PP ultralinear breadboard and I am enjoying listening to it. Sparky.
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