Tone Malone Posted July 28, 2018 Share Posted July 28, 2018 Hi folks, I was reconnecting the my stereo system, and felt an uncomfortable electrical charge through the end of a pair of RCA plugs, just as I was about to connect them to my integrated amp. It didn't feel dangerous, but it did feel stronger and of longer duration than your average static zap. The feeling disappeared a second or so after that, but I then felt a lighter tingle when I came back to it later on. I'll describe the output devices attached to the RCA cable: I have a Fetch TV box with a digital-only audio output. My integrated amp is analogue only, so I attached an inexpensive box that converts the audio optical out to analogue RCA. This little box is charged by a USB, also from out of the back of the Fetch TV box. Yes, the Fetch TV and little box were both on at the time (understand that is not best practice, but then again I'm glad I might have found a potential fault with the system). I haven't re-attached the RCA to the integrated amp after my slightly painful experience with the RCA sockets. I'm requesting the thoughts of those with a good understanding of electronic currents in hifi systems. Does this sound like a serious issue (either safety wise, or to the amplifier and any connected components)? And what would you recommend as the best steps to diagnose the source of the problem? Link to comment Share on other sites More sharing options...
andyr Posted July 28, 2018 Share Posted July 28, 2018 Yes, that sounds like a serious problem, TM. Why don't you try powering the 'little box' which converts optical out into RCA analogue, from a 5v wall wart which has a USB plug. Then at least you are not taking power from the Fetch box - and bcoz it's an optical connection to the 'little box' ... there's no way electric current can be transferred from the Fetch into the little box's case. It sound like, to me, that the Fetch box is either faulty ... or is built/designed wrongly. Somehow, the USB feed is picking up some mains? Andy 1 Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 28, 2018 Share Posted July 28, 2018 Disconnect the ANTENNA from your TV set and get back to us. I betcha that solves the problem. 2 Link to comment Share on other sites More sharing options...
maccdaddy Posted July 28, 2018 Share Posted July 28, 2018 I've also experienced this, albeit with different gear. Zaphod - If the antenna is disconnected and the problem is solved, how do you isolate the leak from the antenna so that it can still be used? Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 28, 2018 Share Posted July 28, 2018 2 hours ago, maccdaddy said: I've also experienced this, albeit with different gear. Zaphod - If the antenna is disconnected and the problem is solved, how do you isolate the leak from the antenna so that it can still be used? You can use an antenna isolator, or just live with it. Or buy a better quality antenna amplifier. BTW: I'd give a 99% probability of solving the problem. Link to comment Share on other sites More sharing options...
wen Posted July 28, 2018 Share Posted July 28, 2018 I have had a similar experience where i was trying to adjust the volume of my amplifier and it went into standby mode the switched on again, same in the car, when i get out i feel a static shock on my leg that is touching the car as i get out, am i electric or what. I have attached a length of copper wire to the turntable earth on the amplifier, i touch this before touching any component of my system, sometimes i get a tingle, but most times not ??? Link to comment Share on other sites More sharing options...
Addicted to music Posted July 28, 2018 Share Posted July 28, 2018 7 minutes ago, wen said: I have had a similar experience where i was trying to adjust the volume of my amplifier and it went into standby mode the switched on again, same in the car, when i get out i feel a static shock on my leg that is touching the car as i get out, You can have earth straps fitted to vehicles to reduce this. Link to comment Share on other sites More sharing options...
wen Posted July 28, 2018 Share Posted July 28, 2018 Is that technically what i have done to the stereo?? Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 28, 2018 Share Posted July 28, 2018 11 hours ago, wen said: I have had a similar experience where i was trying to adjust the volume of my amplifier and it went into standby mode the switched on again, same in the car, when i get out i feel a static shock on my leg that is touching the car as i get out, am i electric or what. I have attached a length of copper wire to the turntable earth on the amplifier, i touch this before touching any component of my system, sometimes i get a tingle, but most times not ??? Different problem. Yours is static electricity. Rip up your carpet and walk around with no clothes on. Problem solved. 4 1 Link to comment Share on other sites More sharing options...
musicmc Posted July 29, 2018 Share Posted July 29, 2018 Seriously Might be an idea to use a multi-meter to actually measure the voltages on the signal cables back to the source of the possible "fault" and replace or repair the item. Getting a painful tingle off any signal cable particularly RCA or Antenna does indicate a fault and could become serious if it gets worse. Have seen antenna amps become lethal hazards in the home in the past. Another potential issue could be a high resistance Neutral connection at point of supply to the system or somewhere else in the home wiring Be safe, get it checked. Link to comment Share on other sites More sharing options...
wen Posted July 29, 2018 Share Posted July 29, 2018 thanks@Zaphod Beeblebrox , but your solution creates a bigger uglier problem( not for me) Link to comment Share on other sites More sharing options...
maccdaddy Posted July 29, 2018 Share Posted July 29, 2018 15 hours ago, Zaphod Beeblebrox said: You can use an antenna isolator, or just live with it. Or buy a better quality antenna amplifier. Thanks for that. Are you referring to the masthead amplifier itself being the problem or the power injector? Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 29, 2018 Share Posted July 29, 2018 (edited) 29 minutes ago, maccdaddy said: Thanks for that. Are you referring to the masthead amplifier itself being the problem or the power injector? The power injector. And, it is not, specifically, a problem, but with the use of double insulated devices, the power is getting into your audio system, via the earths of the equipment. Edited July 29, 2018 by Zaphod Beeblebrox Link to comment Share on other sites More sharing options...
maccdaddy Posted July 29, 2018 Share Posted July 29, 2018 So simply replacing the power injector is the best option? Second to that being to buy an antenna isolator? Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 29, 2018 Share Posted July 29, 2018 51 minutes ago, maccdaddy said: So simply replacing the power injector is the best option? Second to that being to buy an antenna isolator? Nope. Replacing the power injector won't work. The isolator is the only solution. Link to comment Share on other sites More sharing options...
Tone Malone Posted July 29, 2018 Author Share Posted July 29, 2018 (edited) Thanks for the thought-provoking replies. @Zaphod Beeblebrox, I didn't even think about the antenna!!! ... but now that you mention it, I've had a tingle from that plug in the past. I also found these threads/articles interesting, having found the Whirlpool one after ZB suggested the antenna: * https://forums.whirlpool.net.au/archive/950238 * https://www.avhub.com.au/features/hi-fi/im-shocked-why-am-i-getting-a-tingle-394771 My gut feel is ZB is right but, as usual with these things, I tried but couldn't replicate it today. We're due to get our TV antenna replaced, so will have that checked at the same time. @andyr, I'm also going to go with your solution and stop using the USB charge out of the Fetch box. The Fetch boxes really are a "marvel" of cheap engineering (I've been through three of them over four years ...) I'll add to this post if I can further diagnose it. Thanks for your help. Edited July 29, 2018 by Tone Malone Link to comment Share on other sites More sharing options...
mwhouston Posted July 29, 2018 Share Posted July 29, 2018 I get the same burning tingles and have no antenna and mine is not a static issue. I guess the best way to find which device is causing the problem is to shut off one device at a time. Not absolutely conclusive but may help. I think the tingles are coming for a SMPS powering one device. But yet to be proven. Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 29, 2018 Share Posted July 29, 2018 7 hours ago, mwhouston said: I get the same burning tingles and have no antenna and mine is not a static issue. I guess the best way to find which device is causing the problem is to shut off one device at a time. Not absolutely conclusive but may help. I think the tingles are coming for a SMPS powering one device. But yet to be proven. Simply switching off devices may not allow identification of the offending device. You should unplug each device. Link to comment Share on other sites More sharing options...
georgehifi Posted July 29, 2018 Share Posted July 29, 2018 (edited) 8 hours ago, mwhouston said: I think the tingles are coming for a SMPS powering one device. But yet to be proven. Yes I've had this on numerous occasions with laptops and smps chargers, you can feel the tingling through your finger tips if you lightly stroke them (erotically) over certain parts of the laptop/s, another reason beside noise I dislike smp supplies, and most masthead amps have them. Cheers George Edited July 29, 2018 by georgehifi Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 29, 2018 Share Posted July 29, 2018 2 hours ago, georgehifi said: Yes I've had this on numerous occasions with laptops and smps chargers, you can feel the tingling through your finger tips if you lightly stroke them (erotically) over certain parts of the laptop/s, another reason beside noise I dislike smp supplies, and most masthead amps have them. Cheers George It is not, specifically, associated with SMPS. In the cases of masthead amps, it is due to the fact that supply Voltage is fed into the antenna wiring. In other cases, it can be due to the capacitance inherent to ALL transformers. SMPS or linear. Earthed appliances eliminate the problem. However, since few products are earthed any longer, the problem becomes more widespread. Link to comment Share on other sites More sharing options...
georgehifi Posted July 29, 2018 Share Posted July 29, 2018 4 minutes ago, Zaphod Beeblebrox said: It is not, specifically, associated with SMPS. In laptops, so many times it seems to be the case with the cheaper (non original) after market chargers which are smp. Cheers George Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted July 29, 2018 Share Posted July 29, 2018 1 minute ago, georgehifi said: In laptops, so many times it seems to be the case with the cheaper (non original) after market chargers which are smp. Cheers George Again: It is NOT, specifically, SMPS that is the problem. Earthed appliances eliminate the problem. A proper, electrostatic shield in the transformer can greatly reduce the effect. Such things cost money (about $0.05), so many cheap, Chinese manufacturers tend to leave them out. Link to comment Share on other sites More sharing options...
georgehifi Posted July 29, 2018 Share Posted July 29, 2018 (edited) You are probably right then if they leave this shield out of the aftermarket ones in all my cases it was an smp that did it. You can tell the smp ones from the linear by the weight, the smp is light as a feather the linear feels like a half brick. Cheers George Edited July 30, 2018 by georgehifi Link to comment Share on other sites More sharing options...
catman Posted August 2, 2018 Share Posted August 2, 2018 G'day all, an interesting thread. My feelings are that the whole issue stems from the now standard use of 'double insulation' which basically means that nothing is properly 'earthed' anymore and that causes the sorts of 'tingling' problems being talked about here. Regards, Felix. Link to comment Share on other sites More sharing options...
Gremrock Posted August 2, 2018 Share Posted August 2, 2018 On 28 July 2018 at 8:24 PM, Zaphod Beeblebrox said: You can use an antenna isolator, or just live with it. Or buy a better quality antenna amplifier. BTW: I'd give a 99% probability of solving the problem. We have a similar issue at work with the display TV's. I mentioned probably being able to find and remove the problem to the boss one day, and he said he doesn't think it'll kill anyone, but if it does we'll deal with it. Link to comment Share on other sites More sharing options...
Recommended Posts