- Jan 26, 2023
- In the studio!
Based on what I know about RF and gain circuitry, I think direct grounding to the chassis reduces the opportunity to induce RF into the signal because any length of wire acts as an antenna. It's the same reason why it's good practice to keep all wires--signal and ground in a guitar circuit--as short as possible.
In my amp builds I carry all grounds from the board to a common point to cancel any differential in ground potential from various points on the board. But for pots, jacks and tubes, I direct ground to the chassis.
My builds always have very quiet operation.
Yes, jacks isolated though, and "control shafts" are part of pots.Are you using metal jacks and control shafts?
No.If so, do you use a Brass strip, like some amp builders?
End of ground bus wire is extended to a dedicated ring terminal; the last thing that ground bus is connected to, before the terminal, is the (primary) input jack's sleeve connection.How do you make the ground connections from the board- wire with a soldered ring terminal, secured between the washer on a control?
Are you using metal jacks and control shafts? If so, do you use a Brass strip, like some amp builders? If so to both, they all should be at/very close to chassis potential and as long as the connection for the safety/power cord ground has good integrity, no current should flow between these.
How do you make the ground connections from the board- wire with a soldered ring terminal, secured between the washer on a control?
Then I'm cooked. I live in a (large, multi-family) 95-year-old building and my apartment is wired with cloth-and-(dried-up, cracking)rubber-insulated 14 gauge solid; hot and neutral wires only. The grounding is only by virtue of steel conduit and boxes, (newer, NEMA 15) outlets given grounding only through the #6-32 screws fastening them to the boxes. The kitchen was renovated in the '80s, and some outlets and a circuit were added, using BX cable. Recently I checked outlets, and found 2 that were wired with reverse polarity, and 2 others that had no apparent ground (one of those supplied by the 80s BX cable). The former I fixed easily enough; on the latter I disconnected the outlets, jostled the boxes with a large screwdriver, and got some kind of ground, that has 120 V between hot and neutral, and only 112 V between hot and ground -- so I'd say that's an "imperfect" ground.