My sense is that the design engineer knew all of this, but that somewhere in production things got "streamlined" by someone who thought "one ground is as good as another." The electrolytic caps are two separate cans: one with power and output stage grounds, the other with preamp grounds and the preamp's power supply decoupling node.mbene085 wrote: ↑Sat Jan 01, 2022 10:25 amWhat a cool amp, and cool project. It's amazing that someone could go to all the trouble of designing and building this thing without bothering to organize the grounds in a sensible way. Realistically, how much time and effort could it have cost to ground it like you did in the first place? Seems like one of those "ounce of prevention is worth a pound of cure" scenarios.
The two cans are isolated from chassis to give control over where these return paths are routed and terminate. This gives so much potential to do it right! But somewhere along the line, it seems like someone just decided to hook 'em together with one piece of bus wire, tie this bus to the chassis literally wherever, and affix the input stage grounds to it while we're at it.
It was probably a little bit faster on the production line and required one or two fewer pieces of wire (maybe avoided the use of a single phenolic terminal), but way noisier.
Since these were mainly used for quick-and-dirty reference for in the field film editing, it's doubtful anyone cared or objected. They were never supposed to sound great... only just barely usable.
