In Reply to: RE: Phase Shift posted by dave slagle on August 2, 2017 at 11:13:51:
Yes, that's the problem. The grid must be at AC ground. I suppose the reason this doesn't immediately grab everyone's attention is that the same RC network creates significant attenuation of the signal at the grid. After all, that's its purpose (and to bias the grid to the same DC level as the upper section). The problem is, the phase shift is nearly constant at 90 degrees across the audio band, whereas attenuation varies as a function of frequency. Use of this circuit demands that we assume the shift to be inaudible across the entire range of attenuation, whatever it might be, and I don't think it's reasonable to do that. I also think this is the cause of the phenomenon the OP is describing.
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Follow Ups
- RE: Phase Shift - Triode_Kingdom 11:26:17 08/02/17 (7)
- Phase shift probably isn't the problem it appears to be at first glance... - Steve O 14:37:23 08/02/17 (0)
- RE: Phase Shift - sideliner 12:41:27 08/02/17 (0)
- RE: Phase Shift - dave slagle 11:37:08 08/02/17 (0)
- RE: Phase Shift - Caucasian Blackplate 11:33:26 08/02/17 (3)
- RE: Phase Shift - sideliner 13:28:42 08/02/17 (2)
- RE: Phase Shift - Caucasian Blackplate 13:52:34 08/02/17 (1)
- RE: Phase Shift - sideliner 14:13:34 08/02/17 (0)