| Brian Clark |
With a cathode resistor of just 7.33 ohms (3 x 22R in parallel) and 200V across the 6S45P you are going to get a LOT more current pulled than 17mA!
I have found it sufficient to clip the socket tag corresponding to the second grid pin and use just one grid connection with 100 - 150 ohm carbon comp grid stopper. Also I only connect to one cathode pin, letting the others "go hang".
I would suggest you try just 100V B+ and use a 1.2V battery to bias, either a Lithium Anhydride in the cathode (which will be constantly charged) or any similar voltage battery "ars*-up" in the grid circuit.
My experience with this valve type is restricted to power amp applications I'm afraid so may not be relevant to your application ;)
Brian
http://www.sempermusica.com |
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| MIKET |
I need to not stay up so late.
I made a mistake on the cathode resistor.
Here is the corrected diagram, it's also fixed for the link. |
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| Brian Clark |
Aah, that's better! :)
Should fly.
Give it a go and let us know how it works out.
Brian. |
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| Eli Duttman |
| FWIW, Bruce Rozenblit uses a 6c45pi in cascode as the 1st gain block in his phono stage kit. If it works for phono, it will work for a microphone. |
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