Anyone know what this cap is?

[Gaz]

Yes, I see, I totally misunderstood the post you were responding to. I feel like the voltage clamps may be a little overkill because after a certain point the tone change caused by the interaction with the speaker (or lack thereof) effects tone more than a change in preamp voltages. I actually like the idea of the voltages going up, assuming that maybe it will make the preamp a little brighter and stiffer to make up for the dulling effect the scaling has at low volumes. Of course, I haven't A/B'd it or anything.