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You are going into pin 4 (grid) of V4 (6AC7), right?
Did you disconnect the detector diode?
Also, .002 microfarad is too small to drive 5.6k. The low frequency cutoff will be about 14 kHz, causing vertical sync problems.
Since 5.6 k is close to your collector load, it will reduce the AC gain, so disconnect it and replace it with something like 56k. This will lower the cutoff to 1.4 kHz, still too high. Then, to get the low frequency response down to 30 Hz, the coupling cap has to be increased to 0.002x1400/30 = 0.09 (use 0.1 microfarad).
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Last edited by old_tv_nut; 03-10-2017 at 02:39 PM.
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