Final AC15 update

Well, I couldn't help myself. I rearranged (almost) all the ground connections so that they all connect to a bus that connects to the chassis at one point. It worked! The hum is gone. There was also the problem of a noisy volume pot, which turned out to be caused by a leaky coupling capacitor. (Because of the specific design of this amp, there's one place where a capacitor cannot be leaky. And guess where I thought it'd be cool to use an antique cap.)



It's now quiet as a little mouse. It's so cool that I replaced the ugly old cement power resistors with pretty new ones and gave it a sexy blue pilot-lamp jewel -- just to see it smile.