mainframe
Member
- Joined
- Mar 1, 2022
- Messages
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- 13
I have had it with these motherf***ing Volts, on these motherf***ing frames!!
I've seen it for years. Vintage, modern or new. All these supposed "Class II" electronic devices. And I've got 70V AC here on my 6 month old DENON's chassis.
Yet, when they are plugged in and running and my arm is reaching over them to plug in a cable, I feel tingling in my arm hairs and in some cases my eyeballs vibrate. So I whip out the multimeter. Plug the black lead of the multimeter into the earth point of the nearest power outlet, and the red lead of the multimeter onto the offending frame. Sure enough, 70-110VAC on the frame.
Whats worse - I've had this with iPhone and iPad chargers, rendering the damn thing unusable while charging because I can feel the voltage.
Yes - this is only "ghost" voltage and while supposedly not harmful, its damn annoying. I have had this on a few previous amplifiers I eventually just move them on. Now I don't know the exact cause of these voltages, but I suspect in amplifiers it may be eddy currents generating in the chassis from being next to a large transformer, (phone chargers are SMPS so I have no idea)
NOW YOU MIGHT SAY just forget about the voltage as its not doing any harm right? WRONG. I plugged an integrated amplifier with an "AV Bypass" function into the denons front pre-outs to use as an external power amplifier. The speakers. Hummed. Like. Crazy. Classic 'ground loop' hum.
Completely unusable.
So, I did a test with a lead with crocodile clips and linked the DENON frame to earth, the hum VANISHED. The integrated amp in AV bypass was dead silent. couldn't detect/hear any issues. The Denon frame voltage vanished.
Anyway that brings me to the solution - convert the device to electrical class I, that is to connect the frame to mains earth. Not only does this make the device much safer (if your house circuits aren't GFLI protected) but the voltage and any external amp hum completely disappears.
-----
So to get to my question, do any of the wiser heads here object to me replacing the IEC mains inlet on the Denon with a 3 pin one and connecting the frame to mains earth? Normally I would do this on any old device, but because the negative terminals for all the speaker outlets on the DENON are electrically continuous with the frame (I assume the frame is being used for all the audio amp ground returns) I am a bit hesitant it may affect performance or cause something to fail.
I've opened the DENON and removed the mains inlet/standby board and found the exact replacement IEC inlet WITH earth terminal from Rich Bay R-30190(B00) and I could just link the earth terminal to the frame support screw on the standby board. Any objections?
TIA.
Disclaimer: I am an electrical engineer but I have limited knowledge of audio amplifier circuits
I've seen it for years. Vintage, modern or new. All these supposed "Class II" electronic devices. And I've got 70V AC here on my 6 month old DENON's chassis.
- From Wikipedia:
- A Class II or double insulated electrical appliance uses reinforced protective insulation in addition to basic insulation. Hence, it has been designed in such a way that it does not require a safety connection to electrical earth (ground).
Yet, when they are plugged in and running and my arm is reaching over them to plug in a cable, I feel tingling in my arm hairs and in some cases my eyeballs vibrate. So I whip out the multimeter. Plug the black lead of the multimeter into the earth point of the nearest power outlet, and the red lead of the multimeter onto the offending frame. Sure enough, 70-110VAC on the frame.
Whats worse - I've had this with iPhone and iPad chargers, rendering the damn thing unusable while charging because I can feel the voltage.
Yes - this is only "ghost" voltage and while supposedly not harmful, its damn annoying. I have had this on a few previous amplifiers I eventually just move them on. Now I don't know the exact cause of these voltages, but I suspect in amplifiers it may be eddy currents generating in the chassis from being next to a large transformer, (phone chargers are SMPS so I have no idea)
NOW YOU MIGHT SAY just forget about the voltage as its not doing any harm right? WRONG. I plugged an integrated amplifier with an "AV Bypass" function into the denons front pre-outs to use as an external power amplifier. The speakers. Hummed. Like. Crazy. Classic 'ground loop' hum.
Completely unusable.
So, I did a test with a lead with crocodile clips and linked the DENON frame to earth, the hum VANISHED. The integrated amp in AV bypass was dead silent. couldn't detect/hear any issues. The Denon frame voltage vanished.
Anyway that brings me to the solution - convert the device to electrical class I, that is to connect the frame to mains earth. Not only does this make the device much safer (if your house circuits aren't GFLI protected) but the voltage and any external amp hum completely disappears.
-----
So to get to my question, do any of the wiser heads here object to me replacing the IEC mains inlet on the Denon with a 3 pin one and connecting the frame to mains earth? Normally I would do this on any old device, but because the negative terminals for all the speaker outlets on the DENON are electrically continuous with the frame (I assume the frame is being used for all the audio amp ground returns) I am a bit hesitant it may affect performance or cause something to fail.
I've opened the DENON and removed the mains inlet/standby board and found the exact replacement IEC inlet WITH earth terminal from Rich Bay R-30190(B00) and I could just link the earth terminal to the frame support screw on the standby board. Any objections?
TIA.
Disclaimer: I am an electrical engineer but I have limited knowledge of audio amplifier circuits