For idle current around 100 mA, you're going to need 1k Ohm per hundred volts B+ for Class A. If running U-L, the delivered g2 voltage at minimum plate voltage has to deliver a g1=0V current level 2x the idle point. 813's when zero biased, and have g2 toed to plate, run 200 mA around 400V on g2....
Per Waveborn's note, an U-L stage with no other NFB is going to be pretty intolerant of anything but horn loading( with signal not exceeding the horn loading limits ).
cheers,
Douglas
Per Waveborn's note, an U-L stage with no other NFB is going to be pretty intolerant of anything but horn loading( with signal not exceeding the horn loading limits ).
cheers,
Douglas
This time it is not 813, it is ГК-71
+750 under load B+, +360 on G2, +60 on G3, -35V G1, MOSFET follower driving G1, 2 stages, both pentodes. 5K 25W Edcor transformers. Nested feedback loops. 52.4V swing on 8 Ohm load, soft clipping.
Here are pictures, from 20 Hz to 50 KHz. As you may see, despite of nested feedback loops that according to the myth (already out of fashion) cause hard clipping, the clipping is soft, and maximal output power is 42 W per channel.
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Here are pictures on Facebook:
Wavebourn - Here are pictures, from 20 Hz to 50 KHz. As... | Facebook
+750 under load B+, +360 on G2, +60 on G3, -35V G1, MOSFET follower driving G1, 2 stages, both pentodes. 5K 25W Edcor transformers. Nested feedback loops. 52.4V swing on 8 Ohm load, soft clipping.
Here are pictures, from 20 Hz to 50 KHz. As you may see, despite of nested feedback loops that according to the myth (already out of fashion) cause hard clipping, the clipping is soft, and maximal output power is 42 W per channel.
Oops...
Can't attach files... "Upload of file failed"
Here are pictures on Facebook:
Wavebourn - Here are pictures, from 20 Hz to 50 KHz. As... | Facebook
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