What causes feeling of vibration when touching the case of power supply? I believe it is related to grounding? is it magnetic field of transformer? I have verified continuity of AC plug ground prong with the case of power supply at non anodized part, screw attaching transformer to case also has ground continuity. I have little reason to believe that ground is missing from AC mains socket and no way to verify that.
If a power plug of the supply can be reversed in the electrical outlet, that can remove that buzzy feeling you get when rubbing a metal surface of the plugged-in device. Going to a 3-prong plug & cord and then grounding the case would eliminate the effect, too The effect is caused by stray capacitive coupling of the hot mains lead to the chassis. It could also just be resistive leakage causing that, too.
It's a safety hazard if the AC outlet is not properly grounded.
Try measuring the resistance of the screw holding the plastic plate between two different outlets.
If it's an open circuit, at least one outlet has no ground, and perhaps both.
Try measuring the resistance of the screw holding the plastic plate between two different outlets.
If it's an open circuit, at least one outlet has no ground, and perhaps both.
It is a 3-prong plug, will it still help reverse phase-neutral in this case, as those are already fixed in 3-prong plug.
I have a little 3-prong plug-in tester that has 3 neon lamps, two orange and one red that indicate the connections of an outlet into which it is plugged. Two glowing orange and no red means correct connection. The device has a label on it that indicates what is wrong for other glowing combinations of the indicator lights.
You are urged to get a device like this that is suitable for your AC line and socket.
https://www.amazon.com/ELECTRICAL-RECEPTACLE-TESTER-OUTLET-PRONG/dp/B002Q3R7HI
https://www.amazon.com/ELECTRICAL-RECEPTACLE-TESTER-OUTLET-PRONG/dp/B002Q3R7HI
I am not following this, Mains outlet is single 3-prong socket. I am using extension cord. I have verified continuity from ground-prong of extension cord to the chassis. I have tried connecting the power supply plug directly to the mains, it does reduce the effect but does not eliminate it altogether.
Also when I touch the case power supply and simultaneously the case of dac to which it is connected, the effect become stronger.
I wonder if the ground pin in your electrical outlet is floating, i.e., not connected to ground.
That vibrating feeling is commonly caused by capacitive coupling of the mains voltage to the chassis. Swapping the live and neutral connections eliminates it. But the best (safest) solution is to make sure that the chassis is grounded.
The simple outlet tester is a good place to start, but it's easily fooled. An outlet with the neutral wired to the ground pin will show as "correct" on the tester.
You're assuming a US outlet. Outlets in other countries don't always have visible or accessible screws.
Tom
Sure, but he should do what he can do. There's probably around 50V on that chassis, maybe more.
House wiring errors or faults are common. I've seen an entire house wired backwards,
House wiring errors or faults are common. I've seen an entire house wired backwards,
Connecting the power supply plug directly to the mains plug does eliminate atleast 70% of that feeling. But still i can feel it when touching the dac chassis and power supply chassis, more so on the dac chasis.
I will do get the tester and test for proper ground, I have little reason to believe fault in the mains, as in building is wired well according to uk code.
I know the mechanical vibration, that I get from a simple step down transformer I have. Its not the same in this one, This one is well built power supply with toroidal transformer. As i said connected the power supply directly to mains has eliminated most of it but till when touching power supply and dac chassis together, I get varying amounts of this vibration.
I am more concerned with the effect on sound quality rather than the safety of the device though.
thank you, this will be helpful to check it precisely. but as the case is anodized, still can i measure it directly from the case surface or from a grounded point on the case?
This effect seems fairly common and is something I experience at various times. I could even get the effect on my last laptop and also on other devices around the home. In my case its not a fault or problem with the wiring, its just something that is noticeable at some times (sometimes quite markedly noticeable) and it disappears at other times. I have no definitive answer for why it happens.