block diagram
Issues continue, with the v-mid circuit and also with the fx loop. Seems like stuff is breaking, right and left! It had seemed originally that the fx loop was working properly, after I straightened out some circuit errors. But I hadn't actually tested it comprehensively, beyond setting the gain level to be near unity. Just now, when I was trying to use it as part of the regime for testing the new v-mid circuit, it malfunctioned badly. When volume was up near max, it broke into obnoxious squealing. Was it doing that before, and I just hadn't tested it? Or is this due to the chassis being out of the box, with a bunch of test wires going every which way? I need to track down the problem, obviously. I'm not certain that I actually have the chassis securely tied to ground, so that'll be one thing to examine early on. But anyway. I've been feeling increasingly hampered by not having an oscilloscope, for this kind of debugging. ...