sorenj07 said:. . .
edit: paralleling 32-ohm headphones to the 47K load results in a resistance of a tiny bit less than 32. Do I recalculate a new filter based on this? in that case, my highpass frequency is at 1058 Hz, which is pretty wretched. I hope I'm wrong?
No, you're right now !
Same result if you enter 32 as RL in Tube CAD.
Yves.
OK, I guess it could be worse. My B+ voltage is 315, so I'll probably try to fit a 470uF 450V electrolytic per channel (or as large as I can in a 2" deep chassis). I just hope it doesn't decide to blow any time soon. Is there any way to make sure that DC never passes through?
I also have two 100uF 330VAC motor run caps. They'd look really sweet in a tiny chassis. I'm not sure if a 50Hz -6dB point is reasonable though...
I also have two 100uF 330VAC motor run caps. They'd look really sweet in a tiny chassis. I'm not sure if a 50Hz -6dB point is reasonable though...
This brings me to my next question: Should I keep on working at finding a solution to this RC filter or should I use an impedance matching transformer like the ones here?
http://edcorusa.com/products/transformers/xsm/index.html
http://edcorusa.com/products/transformers/xsm/index.html
Actually I've been messing around some more in TubeCAD with this schematic except with a 32-ohm load. Everything holds constant, and I get a 10.4Hz -3dB point using a 220uF capacitor on the output. A 470uF capacitor nets me just under 5Hz for this point. Of course I'll use capacitors that meet safety requirements, but space is also a concern. The plate voltage on the tube, TubeCAD doesn't saw which, is 121V. Does this mean that I can use a capacitor with a rating of 200V or something?
After learning a little bit, I can. Just take the CF part, disregard the coupling capacitor into the upper tube, and input there. Gain is just under 1 and the stage should have NO problem driving a 100K load. You could even use a .22uF capacitor and still have a corner frequency of 7Hz.salas said:Can you show a single ended single stage portion for driving 100K?
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