^ Agreed... but I'm not talking about continuity between panels.
I've simply advised that they check the resistance of that one wire to mains earth. IF the resistance is higher than one would like, AND if it was their intention to have that wire have low resistance to mains earth, THEN the most likely point of failure is the fact that they've simply wedged a wire between the mounting washer of the pot and the anodized / painted front panel...
Now... if they got lucky... all good. A simple resistance check is all that's required to confirm. Me, I'd connect that wire in a different place / different way, but if the desire is to connect that wire in that place... then a little removal of the surface that will be hidden under the pot mount anyway... won't have a negative visual effect over and above the wire itself just smushed in there.
Just my
to take 30s to check the resistance and go from there.
I've simply advised that they check the resistance of that one wire to mains earth. IF the resistance is higher than one would like, AND if it was their intention to have that wire have low resistance to mains earth, THEN the most likely point of failure is the fact that they've simply wedged a wire between the mounting washer of the pot and the anodized / painted front panel...
Now... if they got lucky... all good. A simple resistance check is all that's required to confirm. Me, I'd connect that wire in a different place / different way, but if the desire is to connect that wire in that place... then a little removal of the surface that will be hidden under the pot mount anyway... won't have a negative visual effect over and above the wire itself just smushed in there.
Just my
to take 30s to check the resistance and go from there.
agree
different scenarios of grounding are possible, and (by memory) I believe that Wayne fully covered that issue
now - pot case - it is logical case of it being in connection with case front plate - but as with everything - slight nudge for novices to actually use DMM for intended purposes, is always helpful
speaking of novices - yesterday I killed one Arduino, swapping 5V and 24V wires on pcb
mileage doesn't count, having company in workshop sometimes costs more than coffee and small sip of brandy
different scenarios of grounding are possible, and (by memory) I believe that Wayne fully covered that issue
now - pot case - it is logical case of it being in connection with case front plate - but as with everything - slight nudge for novices to actually use DMM for intended purposes, is always helpful
speaking of novices - yesterday I killed one Arduino, swapping 5V and 24V wires on pcb
mileage doesn't count, having company in workshop sometimes costs more than coffee and small sip of brandy
Yes, the safety ground is connected to the chassis via IEC screw on some bare chassis m I ground down to raw metal (which I just learned is not necessarily necessary?).
The important thing to keep in mind here is that I had trouble figuring out how to do the LED power indicator so... I may not be the best person to reference in this scenario.
In any case, the intent wasn't really to ground it to chassis, but to audio ground. The chassis grounding (if it's even a thing), was by accident.
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It was not. It is mostly to ground to the audio ground. Any grounding to chassis is incidental.
I had a noise issue with this build when using the unit in preamp mode.
I detailed this a bit in post #5110.
The noise issue was troubling at first. I solved it by experimenting.
Now, after looking at the board, there is clearly a flaw with the layout. Maybe it has been discussed, I did not read many of the posts. Noise will not be noticeable with headphones, but it can be significant when using in "preamp" mode attached to an amp with a lot of gain.
If you look at the ground trace that runs from the power supply side to the amp side, next to C11, all of the board current returns thru this trace. The pot and input ground are also on the power side of the board. They are referenced to the wrong ground point. Noise is going to be added.
I'm using a wired pot so it was easy for me to change my input and pot grounds. If you are using the mounted pot and have noise, it can be resolved by cutting the trace shown with a "X" and running a wire between the pot ground over to the ground at the 100 Kohm resistors at the opamp input. You could easily run the wire on the bottom side of the board. It does not need to be heavy gauge. It's essentially what I have done with my wires. I didn't need to cut the trace.
Hope this makes sense.
I detailed this a bit in post #5110.
The noise issue was troubling at first. I solved it by experimenting.
Now, after looking at the board, there is clearly a flaw with the layout. Maybe it has been discussed, I did not read many of the posts. Noise will not be noticeable with headphones, but it can be significant when using in "preamp" mode attached to an amp with a lot of gain.
If you look at the ground trace that runs from the power supply side to the amp side, next to C11, all of the board current returns thru this trace. The pot and input ground are also on the power side of the board. They are referenced to the wrong ground point. Noise is going to be added.
I'm using a wired pot so it was easy for me to change my input and pot grounds. If you are using the mounted pot and have noise, it can be resolved by cutting the trace shown with a "X" and running a wire between the pot ground over to the ground at the 100 Kohm resistors at the opamp input. You could easily run the wire on the bottom side of the board. It does not need to be heavy gauge. It's essentially what I have done with my wires. I didn't need to cut the trace.
Hope this makes sense.
