Ground points

[Ang3lus]

Should all ground points inside an amp read around 0 ohms ? I have this amp here that reads 3 ohms, I guess the grounding needs reworking?

[Firestorm]

Short your meter and make sure it reads 0 ohms first. But yes, 3 ohms is big enough for higher current sections of the amp to develop a troublesome signal across.

[tubeswell]

What Firestorm said. The points in the ground return should have as-low-a-resistance between them as possible in order to avoid voltage occurring between them. If you get voltage differences occurring, then any variations in current at different points within the ground return side of the circuit will cause micro-wobble/signal within that part of the ground return that will be shunted back into the signal path through the filter caps (which are all 'riding' on top of the ground return).

[Ang3lus]

I've checked between the gnd points and I get 3 ohms, which may indicate a loop, but checking between the board mounting screws and other gnd points I get between 8 to 10 ohms, should I scrape more chassis material from where the bolts are mounted ?

[Reeltarded]

You have everything grounded in two spots? One for preamp near inputs and one for everything else near mains? I know you aren't new, just asking.

Is the amp doing anything odd yet? What is the chassis metering when hooked up to both ends of it with the probes ^^^^ (instead of checking with the probes together)

[Ang3lus]

yep, that's how its grounded, it wasn't like that actually before, it was my 2nd build, and only one ground point wasn't as it should, dropped the ohms (and noise also on the clean channel) from 18 ohms to 3 ohms.

when i put probes between, it reads between 6-10 ohms instead of 8-10, so i guess it doesn't mean anything.

I guess it's time to lift the boards, I can't recall if i did something funky back then, but i could have, was new and thought (before reading alot) that you can ground anything anywhere, lucky I only have 2 more GND points beneath the board to check.