aussievintage Posted March 2 Posted March 2 I have had this problem a few times lately. Just about everything comes without an earth pin. I am listening to a phono preamp, connected to a preamp, and then to a power amp - and nothing was earthed. So, of course there was hum. I plugged in an old piece of earthed equipment I wasn't using, and clipped a lead onto it's case and onto the case of one of the items I was using. No more hum ! It has happened more than once - and there's never anything nearby that is earthed, not even the computer in the same room. I am considering making up a mains plug with nothing but the earth wire connected, to use as an earthing point for stuff - but I'll bet that is illegal.
andyr Posted March 2 Posted March 2 Interesting, av. 3 hours ago, aussievintage said: I have had this problem a few times lately. Just about everything comes without an earth pin. I am listening to a phono preamp, connected to a preamp, and then to a power amp - and nothing was earthed. Everything that I make ... uses a 3-wire power cord, with the chassis connected to the earth pin of the IEC socket. (That is - except for the SLA-powered versions of my Muse phono stage & preamp ... and the Paris headamp.) 3 hours ago, aussievintage said: So, of course there was hum. Alas ... yes. 3 hours ago, aussievintage said: I plugged in an old piece of earthed equipment I wasn't using, and clipped a lead onto its case and onto the case of one of the items I was using. No more hum ! 3 hours ago, aussievintage said: It has happened more than once - and there's never anything nearby that is earthed, not even the computer in the same room. Again, everything I make has an earth terminal ... connected inside the case via a star washer, with the case paint/anodising ground away to bare metal, around the hole. 3 hours ago, aussievintage said: I am considering making up a mains plug with nothing but the earth wire connected, to use as an earthing point for stuff - but I'll bet that is illegal. That is a simple solution - which I have employed from time to time in customers' systems. Even if you don't have an electrician's ticket (so beloved by Bob) as you are only connecting a wire to the earth pin - and not touching Active or Neutral - I can't see how it contravenes any electrical standards/certification. 1
aussievintage Posted March 2 Author Posted March 2 1 minute ago, andyr said: Everything that I make ... uses a 3-wire power cord, with the chassis connected to the earth pin of the IEC socket. (That is - except for the SLA-powered versions of my Muse phono stage & preamp ... and the Paris headamp.) Mostly the problem is commercially made stuff running on a plugpack, or double insulated. In both - no earth pin. 3 minutes ago, andyr said: Again, everything I make has an earth terminal ... connected inside the case via a star washer, with the case paint/anodising ground away to bare metal, around the hole. Hard to do in a plastic case (for example) 2 minutes ago, andyr said: That is a simple solution - which I have employed from time to time in customers' systems. Even if you don't have an electrician's ticket (so beloved by Bob) as you are only connecting a wire to the earth pin - and not touching Active or Neutral - I can't see how it contravenes any electrical standards/certification. Wouldn't mind betting that if it is to be inserted in a wall outlet - you will contravene something. 2
andyr Posted March 2 Posted March 2 1 minute ago, aussievintage said: Mostly the problem is commercially made stuff running on a plugpack, or double insulated. In both - no earth pin. True. So, in the case of my Muse and Paris ... an earth terminal is supplied, to take a grounding wire from. 1 minute ago, aussievintage said: Hard to do in a plastic case (for example) Plastic cases don't shield the internal circuits from RFI/EMI ... so are 'haram', in my view. 1 minute ago, aussievintage said: Wouldn't mind betting that if it is to be inserted in a wall outlet - you will contravene something. You may well be right. Bureaucratic stupidity knows no bounds. 1
Spinspin69 Posted March 2 Posted March 2 (edited) I remember watching a video on YT recently. Since we stared using RCD's in our homes that the neutral is now convection to ground. So 2 pin or 3 pin your still grounded. Edited March 2 by Spinspin69
andyr Posted March 2 Posted March 2 52 minutes ago, Spinspin69 said: I remember watching a video on YT recently. Since we started using RCDs in our homes ... the neutral is now connected to ground. So 2 pin or 3 pin you are still grounded. Now that is a very interesting issue! @bob_m_54? 1
Addicted to music Posted March 2 Posted March 2 I use to have a phono amp when i take the cover off it use to pick up CB radio.... Scared the crap out of me the 1st time it happened.... 1
aussievintage Posted March 2 Author Posted March 2 (edited) 1 hour ago, Spinspin69 said: I remember watching a video on YT recently. Since we stared using RCD's in our homes that the neutral is now convection to ground. So 2 pin or 3 pin your still grounded. Always was. It's called a MEN or multiply earthed neutral system. Doesn't help though, because the active and neutral go through a transformer (in the equipment's power supply) which isolates the AC from earth. Edited March 2 by aussievintage 3 1
aussievintage Posted March 2 Author Posted March 2 22 minutes ago, andyr said: Now that is a very interesting issue! @bob_m_54? http://www.electricalaxis.com/2016/10/what-is-multiple-earthed-neutral.html 2
bob_m_54 Posted March 3 Posted March 3 19 hours ago, andyr said: Even if you don't have an electrician's ticket (so beloved by Bob) Don't know where you get that idea. But if it's from where I think, all I was saying is it's not a good idea to suggest certain DIY jobs to people who aren't necessarily experienced or familiar with electrical wiring on mains equipment. I make lots of mains chit and used to do quite a few mains lead replacement/repairs, and don't have and "electrician's ticket" , when I had my business. I have even worked on industrial electrical equipment and wiring systems, and repaired mains equipment, as part of a previous job, without an "electrician's ticket"
bob_m_54 Posted March 3 Posted March 3 (edited) 15 hours ago, andyr said: Now that is a very interesting issue! @bob_m_54? There will be an Earth-Neutral link in the mains switchboard. But the equipment with only an A & N mains lead is double insulated between mains and chassis (known as Class II), so no, the chassis is not connected to Earth nor Neutral. Edit: Actually, that this is not understood by many people, only goes to reinforce my post above, with regards to some people not doing mains DIY jobs. Edited March 3 by bob_m_54 more 2
aussievintage Posted March 3 Author Posted March 3 20 minutes ago, bob_m_54 said: that this is not understood by many people, only goes to reinforce my post above, with regards to some people not doing mains DIY jobs. Exactly. Actually, the bulk of people will look at you blankly when you speak of active and neutral even - and THEY should not be attempting this stuff. 1
075Congo Posted March 4 Posted March 4 I have 2 power cords (Shielded) connecting my SACD Player and Integrated amp. Both have earthing as well. In my SACD User Manual they state there "may" be some advantage in connecting the "Chassis Ground" on the rear of the SACD player to the chassis on the integrated. Is this a pointless exercise? I have also used Entreq Grounding boxes but cannot pick up any sonic changes /improvements.
aussievintage Posted March 4 Author Posted March 4 5 hours ago, 075Congo said: I have 2 power cords (Shielded) connecting my SACD Player and Integrated amp. Both have earthing as well. In my SACD User Manual they state there "may" be some advantage in connecting the "Chassis Ground" on the rear of the SACD player to the chassis on the integrated. Is this a pointless exercise? I have also used Entreq Grounding boxes but cannot pick up any sonic changes /improvements. It isn't about improving the sound.
bob_m_54 Posted March 4 Posted March 4 9 hours ago, 075Congo said: I have 2 power cords (Shielded) connecting my SACD Player and Integrated amp. Both have earthing as well. In my SACD User Manual they state there "may" be some advantage in connecting the "Chassis Ground" on the rear of the SACD player to the chassis on the integrated. Is this a pointless exercise? I have also used Entreq Grounding boxes but cannot pick up any sonic changes /improvements. The shielding on your power cables connected to your gear are unlikely to do much except possibly eliminate hum from the mains current running through them affecting any interconnect cables that are running very close to them. The grounding boxes.. hmmm . The fact that they also make grounding boxes for you car, to ground the chassis, has got to give you a clue about them. If your SACD player has a 2 pin power plug, then it is double insulated, so no worry about it being unsafe. And unless you're picking up hum, with the SACD player connected to the amp, then grounding the chassis to the amp isn't going to do anything.
andyr Posted March 4 Posted March 4 10 hours ago, 075Congo said: I have 2 power cords (Shielded) connecting my SACD Player and Integrated amp. Both have earthing as well. In my SACD User Manual they state there "may" be some advantage in connecting the "Chassis Ground" on the rear of the SACD player to the chassis on the integrated. Is this a pointless exercise? 37 minutes ago, bob_m_54 said: The shielding on your power cables connected to your gear are unlikely to do much except possibly eliminate hum from the mains current running through them affecting any interconnect cables that are running very close to them. If your SACD player has a 2 pin power plug, then it is double insulated, so no worry about it being unsafe. And unless you're picking up hum, with the SACD player connected to the amp, then grounding the chassis to the amp isn't going to do anything. ^ ^ ^ what the man sez!
Recommended Posts