Feeling mild current when touching the body of B50 amp

I can feel mild current when I touch the metal body of B50. The tester lights up when i keep it on the GND knob on the backside of the B50. Can anyone suggest how to solve this.


@Sanath it would be good to know the exact circumstances, e.g. with which devices is the B50 connected. If there is a galvanic connection with a TV, what is the design of the power supply, etc.

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@zitev Thanks for the response. My B50 is connected to LG TV with HDMI ARC cable. LG Blu ray player is connected to TV with HDMI cable. Current can be felt on the player also. No other device is connected to B50. Power supply to TV, B50 and Blu ray is from the same power point using a multi socket adapter.

@Sanath ok if you pull the TV cable out of the B50, and then measure the voltage between the device case and the ground again, is there a change?

@zitev Thanks for the guidance. But I am not technically familiar with measuring voltage. I do not have any equipment also. One thing is for sure. The problem is with the power point. If I connect only TV to the power point, I can feel the mild tingle when I touch the hdmi cable connected to TV and the tester also glows. So I am now looking for a electrician to check the earthing in my apartment.

@Sanath Based on your description, there is a good chance that there is no problem with the grounding of the apartment, at least this phenomenon is caused by the ground loop that forms between the cable TV coax and the grounding network of the apartment (the two grounding points are at different potentials, current flows between them). This is a very good solution galvanic isolation of the TV cable, for which this solution can be perfect: https://tiitech.com/product/220/
find a cable TV installer who will install one at the entry point of the coax cable into the apartment, this will eliminate the problem!

But @zitev , there is no cable TV connection to the TV. No satellite dish is connected to the TV. I use TV only to watch Youtube, Amazon Prime and Netflix. All built in apps.

@Sanath OK, the TV has a double insulated power supply and the amplifier has a switching power supply. For the latter, the operating condition is that it can only be connected to a socket with a protective ground, otherwise a part (even half) of the supply voltage may appear on the device housing (and on the components in galvanic contact with it, on the shielding of cables, etc.), so if you touch it, you can feel it! In this case, it is worth checking whether there is continuity of the grounding in the socket or in the amplifier connection line.

@zitev Ok. I will check. I appreciate your prompt responses :+1:

Right or wrong, I do not know. What I have done now is, I connected a wire to ground terminal on B50 and the other end to the earth pin of the 3 pin plug and plugged to the outlet. Now I can’t feel the current on the body of B50 and also the hdmi cable from tv. Is this ok. Or is there any risk.

@Sanath this is not a good solution, the grounding point is used to connect the shielding of other audio equipment (e.g. turntable) here - the grounding of the device housing (if necessary) must be done via the power supply - if this is not possible here, then it is as intended (e.g. . the power supply unit is double-insulated - in this case it is forbidden to ground the housing of the device!), or the power supply unit is connected incorrectly, because, for example, the grounding is missing from the socket, the plug, something is not connected inside the power supply unit, etc. it can be a problem from a life safety point of view, if voltage appears on the grounding, then the housing of the device will also be live.

Do you still feel the current tingle when the unit is disconnected from other sources?
If you do then the power supply is most probably faulty, maybe the Y capacitor in the supply?

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@zitev As you suggested, I have disconnected the wire from the GND terminal on the amp and GND pin of the socket. I also thought it may not be the right solution. I think I will ignore it for the time being or may be sometime later get the power point checked by an electrician.
The mild current can be detected by a tester on the terminals of the speaker also which means the speaker wire is carrying the mild current to the speakers also. I am worried whether this will do any harm to the speakers or whether it will affect the performance of the speakers.

@Steve1 Yes, I can feel the current even if all the sources are disconnected.

@Sanath based on what has been said, this is clearly a lack of grounding, which either simply refers to the failure of the socket or the power cable, but in a more complex case it may also be a technical or design fault of the switching power supply (as @Steve1 also mentioned, the absence or rupture of the Y-capacitors - the common junction of capacitors is connected to the ground, otherwise the supply voltage is connected to the device housing, see also PC power supplies)… since in this case there is no disturbance in the operation of the device, the problem occurs only in relation to the ground - the device can be used, you just don’t need to touch it very much … an electrician measures the fault in seconds, which can be a socket, cable or power supply…

Thanks @zitev and @Steve1 . Very insightful discussion we had. Will check with an electrician and hopefully the issue will be solved. Thanks once again.

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