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Getting rid of ground loops: What is the best option? - Page 2

post #16 of 38
Quote:
Originally Posted by chewy4 View Post

Yep, in the case of ground loops that's what they tell people to use. Both in the Asgard manual and they've recommended me use one via email.

 

There have been cases of people getting electrocuted by them but I'm more concerned about my gear. I can just turn the amp off whenever I'm messing with the plugs.

I am gonna go look through the manual now, I could be completely mistaken the violation of eq code then. 

post #17 of 38
Thread Starter 
Quote:
Originally Posted by paradoxper View Post

I am gonna go look through the manual now, I could be completely mistaken the violation of eq code then. 

It's the first question in the FAQ in the manual.

post #18 of 38

No, cheater plugs are most certainly dangerous. In the event that a live mains connection inside a device without a ground touches a metal chassis, the metal casing and entire signal chain could be at mains voltage. It's fairly rare for it to happen but it DOES happen, and when it happens, all of your equipment and anyone touching it will have a very very bad day. This isn't something to mess around with.

 

http://www.ehow.com/info_11373614_three-prong-plug-converter-safety.html

post #19 of 38
Quote:
Originally Posted by chewy4 View Post

It's the first question in the FAQ in the manual.

Yep, you're right. Even if the cheater is grounded, it offers no protection.

post #20 of 38
Quote:
Originally Posted by Steve Eddy View Post

Any piece of equipment sold with an IEC-320 C14 receptacle on it should be assumed to NOT meet Class II specs (i.e. double insulated) and should ALWAYS be used with a three prong cord without the safety ground defeated. No, defeating the safety ground doesn't put you in grave and imminent danger, but defeating it does defeat a rather important safety measure. In the event of a failure that puts the AC hot lead in contact with the chassis (the safety ground should be connected to the chassis by the shortest and most direct means), it provides a return path for fault currents rather than you (and more importantly your heart) being that return path.

 

And the plugs people use as "cheater" plugs are NOT intended to DEFEAT the safety ground. They're intended to PROVIDE a safety ground for two prong outlets. The metal tab or pigtail is intended to be secured to the metal outlet box by way of the outlet cover screw. In many old homes with two prong outlets, while there is no safety ground in the outlet, they do have a safety ground in the mains wiring that's connected to the metal outlet box.

 

I love Jason, but I think it's irresponsible for any manufacturer to recommend defeating the safety ground if their equipment is fitted with C14 receptacles. If the equipment meets Class II specs, it can be sold with a regular two prong cable or receptacle. 

 

se

What if the grounding tab is connected to electrical ground? Would things be ok, then?

post #21 of 38
Quote:
Originally Posted by paradoxper View Post

What if the grounding tab is connected to electrical ground? Would things be ok, then?

 

Which "grounding tab" do you mean and what do you mean by "electrical ground"?

 

se

post #22 of 38
Quote:
Originally Posted by chewy4 View Post

I'm currently using a three to two prong adapter on my amp, but apparently this is extremely dangerous.

 

Anyone know of any other solutions?

 

I've heard of ground loop isolators, but do they degrade the sound quality? It seems like they could mess with the sound a bit.

 

Are there better options?


My understanding is that there are standards about grounding of consumer electronics. If a fire results from connecting non-standard equipment to the power line, your fire insurance could be invalid.

 

My stereo equipment has input and output jacks NOT grounded directly to the chassis. Instead signals converge to some single point within that is grounded. If you have complex setup that has hum problem, you could try disconnecting everything and adding back one at time to see where the problem occurs.

 

If all fails, you might need balanced or differential amplifiers.

post #23 of 38
Quote:
Originally Posted by Steve Eddy View Post

And the plugs people use as "cheater" plugs are NOT intended to DEFEAT the safety ground. They're intended to PROVIDE a safety ground for two prong outlets. The metal tab or pigtail is intended to be secured to the metal outlet box by way of the outlet cover screw. In many old homes with two prong outlets, while there is no safety ground in the outlet, they do have a safety ground in the mains wiring that's connected to the metal outlet box.

 

As per a cheater plug that has the grounding tabs. Does that make it safe? I'd think a spike or surge would toast any equipment.

Which would lead to ask if the only "safe" alternative is an isolator or simply replacing the two prong receptacle with a GFCI?


Edited by paradoxper - 11/2/12 at 10:06pm
post #24 of 38
Quote:
Originally Posted by paradoxper View Post

As per a cheater plug that has the grounding tabs. Does that make it safe? I'd think a spike or surge would toast any equipment.

Which would lead to ask if the only "safe" alternative is an isolator or simply replacing the two prong receptacle with a GFCI?

 

Regardless of whether grounding the cheater plug is safe, you will get a ground loop again anyway, making the cheater plug useless.

 

I would personally just sell the Asgard and get a Class II amplifier that does not use a 3 prong AC connector. Otherwise, if replacing the Asgard is not an option, ground isolation could also be added between the PC and the DAC (of course this excludes internal sound cards), either by using optical S/PDIF, or a USB isolator that is cheaper than a high quality audio transformer.


Edited by stv014 - 11/3/12 at 3:32am
post #25 of 38
Quote:
Originally Posted by stv014 View Post

 

Regardless of whether grounding the cheater plug is safe, you will get a ground loop again anyway, making the cheater plug useless.

 

I would personally just sell the Asgard and get a Class II amplifier that does not use a 3 prong AC connector. Otherwise, if replacing the Asgard is not an option, ground isolation could also be added between the PC and the DAC (of course this excludes internal sound cards), either by using optical S/PDIF, or a USB isolator that is cheaper than a high quality audio transformer.

Regardless, safety is the whole focus of my question. 

post #26 of 38

Hey all,

 

To clarify some things:

 

1. Take a look at the back of a new Sony Blu-ray player. 2 prong cord. Take a look at the back of a new Emotiva amp. 2 prong cord--with IEC input. So, it shouldn't automatically be assumed that "3 prong good, 2 prong evil."

 

2. Like these items, our products are technically double-insulated. There is no single failure that can put AC on the case. 

 

3. If you are serious about your AC power, you should check your house wiring to ensure that it isn't wired in reverse, and that it actually has a ground. You'd be amazed how many homes have problems. We ran into all sorts of crazy stuff in the new Schiit office--test gear acting bizarre, audio analyzers returning bad results--and had to rewire a lot of the outlets to ensure both ground and correct wiring. There are inexpensive testers that detect reversed AC wiring or no ground.

 

3. The recommendation for cheater plugs is something we've done since the 1980s, in both Sumo and Theta gear. It sounds like these days we should be recommending a GFCI or ground loop isolator instead, so that's what we'll do--we'll revise the manuals to reflect this. 

 

Hope this clears things up.

 

All the best,

Jason

post #27 of 38

Thanks for the explanation, Jason.

post #28 of 38
Thread Starter 

Thanks Jason!

 

As for the GFCI route, would plugging one of these into my power strip do the trick: http://www.amazon.com/Plug-In-GFCI-Surge-Protector/dp/B000MM3Z6C

 

Or would I need to get a whole new GFCI power strip for both devices?

 

It seems like that would be the best option for both safety and to avoid messing with actual sound signal.

post #29 of 38

This is what Audio Precision sometimes does.

700

post #30 of 38

The Ebtech Hum X works well and isn't too much of a rip-off. Alternately, I haven't heard any degradation with a cheapo ground loop isolator.

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