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Ok... A little full disclosure. Biasing hot in the circuit examples was something I arrived at while trying to get what looked like a reasonable waveform. With the 220k plate for the previous stage and 100k plate and cathode on the cathodyne the grid bias looks to be about -.5V. In a typical DC coupled cathodyne with all symmetrical loads of, let's say, 100k the bias is about -1.2V.
Since the goal of the OP is to get that particular distortion of the cathodyne used with a post PI master I ran some more sims to see how this might be accomplished. Taking teemuck's tip that we're trying to simulate a whole amp here. Below in the first simulation is the circuit output at the load on the OT when using a -1.2V biased cathodyne and a post PI master.
Rather than employ diodes or feeding both DC coupled cathodyne outputs to a differential amplifier I found that the plate output of a hot biased cathodyne (with the cathode of the cathodyne loaded) seems to get pretty close. So I think the easiest solution would be to simply feed this plate output to a following PI through a master volume control.
Since the goal of the OP is to get that particular distortion of the cathodyne used with a post PI master I ran some more sims to see how this might be accomplished. Taking teemuck's tip that we're trying to simulate a whole amp here. Below in the first simulation is the circuit output at the load on the OT when using a -1.2V biased cathodyne and a post PI master.
Rather than employ diodes or feeding both DC coupled cathodyne outputs to a differential amplifier I found that the plate output of a hot biased cathodyne (with the cathode of the cathodyne loaded) seems to get pretty close. So I think the easiest solution would be to simply feed this plate output to a following PI through a master volume control.
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