Hello All, I've been working on a LTP using a 12BH7 driven by a 12AX7 cathode follower. Here's the current design: The load line (for the left triode with Ra = 27K) should look like this: The bias is sitting at Vgk = -9.2V with -10.8V of negative signal swing available before the tube should cut off at Vgk = -20V. As this is a LTP, the headroom is actually doubled, so the signal should be able to swing -21.6V negative before cut off is reached. The total input headroom should be around 40Vp-p if this were perfectly center biased. Under those conditions the unloaded output signal swing should be about 200Vp-p. So I am confused by why I am getting clipping on the negative signal swings like this: The yellow trace is the input signal which is 36Vp-p. You can see that the output signal (green) of the left triode is really clipping it's positive peaks and sloped heavily. This is loaded by a 1M volume control turned all the way down, so no grid current from the following stage should be charging the 1n coupling cap. I can't for the life of me figure out why this is happening. Why is it clipping so early and sloping like that? Am I missing something obvious?