Posted by Russ [ 209.214.20.85 ] on December 31, 2005 at 16:26:18:
In Reply to: Hey Russ... posted by PakProtector on December 31, 2005 at 11:58:57:
it was John...same last name but different guy.
I agree with many of your points. I can't see the miller thang either...maybe he did mean with regards to the driver tube....but I didn't read it that way and neither did Mark.
The way I see it any choke small enough to provide a low enough impedance path to ground when the tube was driven positive at higher frequency would have too low of an impedance at 20 hertz (even 250 henries at 1K is more Z than many output tubes can handle). Me thinks a grid leak resistor near maximum allowable value is prudent. Add in the fact a choke is an energy storage device and balance with the notion that it's impedance might go to hell once grid current sets in and we have a host of things to consider (with no good manf. info to design from and I won't even go into the 3dB points and Q).
I suppose you might feel I weighed in on the wrong side of the 1/2-1/4 a-a thing. IIRC my main comments were 1/2 the OPT does have 1/4 the Z and the normal way of picking a load line was nothing more than an easy mathmatical convention not based in reality. But regardless, if I have not done so before, allow me to publically state beyond any shadow of a doubt that you were right.
Nice chewing the audio fat and have a happy new years.
Russ
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