Today when reconnecting the RCA cable from the subwoofer to the amp I was
surprised to receive a shock from the male connector the moment i
touched the amp pre-out plug. To be more clear, both the amp and the
sub were turned off but still plugged-in in to the AC outlet. The one
end of the RCA cable was plugged into the sub while the other was in
my hand. The moment a touched the Amp pre out while holding the rca
cable in my hand i felt the current shock which was "mild" and
unpleasant. So i went to investigate furthermore.
First, i disconnected everything from the amp including the power cord
and the external DAC and afterwards i connected the sub. No
shocks everything fine. Then i went to connect back the DAC
and boom, again shocks on my fingers. Now I'm even more confused, i
unplugged the sub from the amp and tried again to connect the DAC alone. Again, everything fine no shocks. So, everything is
fine as long as only one device is connected to the amp. The moment i
try to connect the second device no matter which one is first i always
get current shocks on my fingers.
And the last and most confusing thing:
Amp power cord detached, DAC power cord detached, Sub power
cord placed in AC outlet but turned off. NO RCA connections between
units. First, I went to plug the rca sub to the amp, no problems.
Then, i took the rca cable from the DAC (which is
disconnected from power) and tried to plug to the amp which is also
disconnected from power. Guess what, again current shock on my
fingers.
Im really confused. Why and what is happening?
surprised to receive a shock from the male connector the moment i
touched the amp pre-out plug. To be more clear, both the amp and the
sub were turned off but still plugged-in in to the AC outlet. The one
end of the RCA cable was plugged into the sub while the other was in
my hand. The moment a touched the Amp pre out while holding the rca
cable in my hand i felt the current shock which was "mild" and
unpleasant. So i went to investigate furthermore.
First, i disconnected everything from the amp including the power cord
and the external DAC and afterwards i connected the sub. No
shocks everything fine. Then i went to connect back the DAC
and boom, again shocks on my fingers. Now I'm even more confused, i
unplugged the sub from the amp and tried again to connect the DAC alone. Again, everything fine no shocks. So, everything is
fine as long as only one device is connected to the amp. The moment i
try to connect the second device no matter which one is first i always
get current shocks on my fingers.
And the last and most confusing thing:
Amp power cord detached, DAC power cord detached, Sub power
cord placed in AC outlet but turned off. NO RCA connections between
units. First, I went to plug the rca sub to the amp, no problems.
Then, i took the rca cable from the DAC (which is
disconnected from power) and tried to plug to the amp which is also
disconnected from power. Guess what, again current shock on my
fingers.
Im really confused. Why and what is happening?
That type of chock has been experienced for decades. No deaths as far as I know.
Why? I know two types of reasons:
For long, some manufacturers connected chassis to a mid-point formed between two safety-capacitors being connected between primary phase and return. Thus, that mid-point should unloaded have half the primary voltage (115Vac/230Vac) but due to the safety capacitors, the current that can be drawn is very little and safe. I guess the reason for this connection was noise emission. In case you have an earth connection, that earth will be connected to chassis and you will feel nothing.
The second situation is SMPS that use a safety capacitor between primary and secondary sides for EMI reasons. Again, you can feel this unpleasant tickling but as the current is kept at a safe level by the safety capacitor, there is no danger.
Most likely you do not have a (safety) earth connection or you do not use it. Most chassis/cabinets are covered with an insulating layer (paint/wood/plastic....) such that you rarely feel the tickling but the connectors at the rear have a low impedance connection to the chassis and they are "naked" for good electrical connection to the cables.
Why? I know two types of reasons:
For long, some manufacturers connected chassis to a mid-point formed between two safety-capacitors being connected between primary phase and return. Thus, that mid-point should unloaded have half the primary voltage (115Vac/230Vac) but due to the safety capacitors, the current that can be drawn is very little and safe. I guess the reason for this connection was noise emission. In case you have an earth connection, that earth will be connected to chassis and you will feel nothing.
The second situation is SMPS that use a safety capacitor between primary and secondary sides for EMI reasons. Again, you can feel this unpleasant tickling but as the current is kept at a safe level by the safety capacitor, there is no danger.
Most likely you do not have a (safety) earth connection or you do not use it. Most chassis/cabinets are covered with an insulating layer (paint/wood/plastic....) such that you rarely feel the tickling but the connectors at the rear have a low impedance connection to the chassis and they are "naked" for good electrical connection to the cables.
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Thanks FauxFrench for your replay.
Im using the system several months no issues at all. Also, i cant hear any hum or noise from the speakers or sub which is also nice. Im just scared if that current can damage my amp and/or dac or subwoofer
Thanks again
I wasn't worried about my death but rather for the equipment
Im using the system several months no issues at all. Also, i cant hear any hum or noise from the speakers or sub which is also nice. Im just scared if that current can damage my amp and/or dac or subwoofer
Thanks again
I don't think i was clear I'll try to explain with simple example.
Sub connected to amp via RCA, DAC is on, but still not connected to the amp. In my right hand i hold the two male rca jacks from the DAC and then, if i touch the chassis of the amp with my left hand i feel the current in my right hand from the male jacks from the external DAC. This is case only if the sub is connected to the amp. If i unplug the sub from the AC outlet or remove Sub's rca jackets, no current shocks at all
Sub connected to amp via RCA, DAC is on, but still not connected to the amp. In my right hand i hold the two male rca jacks from the DAC and then, if i touch the chassis of the amp with my left hand i feel the current in my right hand from the male jacks from the external DAC. This is case only if the sub is connected to the amp. If i unplug the sub from the AC outlet or remove Sub's rca jackets, no current shocks at all
Until you connect the sub your system is most likely floating ( none of the chassis are earthed )and less likely to receive a shock . When you fully connect the sub including the AC outlet ( no need to be powered on ) you provide a earth connection to the amp through the RCAs to the amps chassis and are now more likely to receive a shock .
Thank you epicyclic,
What should i do in that case, do i need to "earth" the amp chassis? How can i do that? Is this a potential damage to my system?
Im really noob when it comes to this staff and i dont know what does it mean double insulated. The model of the DAC is Marantz NA8005 and the model of the sub SVS SB-1000. Both are connected to normal house AC outlets. I live in Europe (Macedonia) and the outlets looks like this https://2usb.eu/media/textboxes/image/j/u/jung_schuko_steckdose_mit_usb_1.jpg
Both your sub and DAC are double insulated and I believe your amp is also ( from previous posted photos, what is the model of you amp , just to confirm ) ( so none of these require a safety earth connection because by definition they are double insulated against the AC outlet voltage coming into contact with metal work .So without any earthed metal work why are you receiving shocks !! As I cant be sure exactly what you are dealing with I would advise that you get your system professionally checked over . Your safety is my primary concern .
PS.. the double insulated symbol is a box within a box .
PS.. the double insulated symbol is a box within a box .
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Finally i located the problem and i know how to reproduce it. Please take a sit before reading this
The only thing that i need to do if i want to "toggle" the current shocks is to unplug the cable from the outlet rotate for 180 degrees and then attach again. Please take a look at this video for more clarification Shared album - Hristijan Curukoski - Google Photos .
Now that you know how do i trigger the shocks please shed some light why is this happening
The only thing that i need to do if i want to "toggle" the current shocks is to unplug the cable from the outlet rotate for 180 degrees and then attach again. Please take a look at this video for more clarification Shared album - Hristijan Curukoski - Google Photos .
Now that you know how do i trigger the shocks please shed some light why is this happening
With these power socket (and correct use) you have a safety earth. They are similar to the power sockets used in NL.
As such you can connect all signal returns to safety earth (star structure) such that all returns you touch have the same potential even before being connected. Then, no more tickling.
As such you can connect all signal returns to safety earth (star structure) such that all returns you touch have the same potential even before being connected. Then, no more tickling.
I adhere to the fauxfrench explanation. Those are called "Y" capacitors and are put there to decouple RF currents. Also X are placed between line and neutral for the same reason. Also for the rectified line and earth to give return to the primary side to displacement currents trough transformer inter winding capacitances.
Finally i located the problem and i know how to reproduce it. Please take a sit before reading this
The only thing that i need to do if i want to "toggle" the current shocks is to unplug the cable from the outlet rotate for 180 degrees and then attach again. Please take a look at this video for more clarification Shared album - Hristijan Curukoski - Google Photos .
Now that you know how do i trigger the shocks please shed some light why is this happening
That is what I want to suggest to measure. If the phases are right connected to the transformer primary then it is no light oh the simple handy screwdriver probe touching the core of the transformer. If Live and Neutral are swapped / not properly connected to the primary, then on the magnetic core - body of the transformer probe will ligts. Live is always going to the beginning of the wire layers. Sometimes it could be seen where is the wire is in the first layer to the inside core of the transformer. (that is not that easy to spot with the toroid type). Byt toroid types cores are inside the layers and often not connected...
.
Commonly EI types of the transformers connected directly to the chases bu the core. If the L/N is out of the phase than will be the "light" on the chases too.
Proper way, like brands did early days is to right connect phases on the primary AND to isolate transformer core from the chases. THEN with separate wires connect core, screens and shields to earth in the same point like chases
is... So every power transformer should be in phase connected.
...
But guess what.
I checked euro type power cables - half of about 10 was opposite L/N connected. Jus these old cables from older equipment was good connected......
Next check the wall inlets for simple test with probe on neutral and shucko must not indicate light.
From the photo - there are NO earth connection. Because of the jus 2 wire power line jack... That is what I explained. One or more power transformers are EI types and directly connected to device box...
...
It will be the best to take equipment to some professional shop, and ask to replace the power cable with 3 wire standard cable, and check for the proper primary transformers conections.
.
Take a care.
.
One thing You mention, that it is not the same during the day leeding to conclusion that other things in the building is not say questionable. Probably shocks are happening after the people get back from job. And turn in home kitchen devices...
Just one more reason to replace cables and proper earth power lines.
Cheers
...
It will be the best to take equipment to some professional shop, and ask to replace the power cable with 3 wire standard cable, and check for the proper primary transformers conections.
.
Take a care.
.
One thing You mention, that it is not the same during the day leeding to conclusion that other things in the building is not say questionable. Probably shocks are happening after the people get back from job. And turn in home kitchen devices...
Just one more reason to replace cables and proper earth power lines.
Cheers
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