My Final Grounding Question

[mcduman]

amirm et al,

The whole grounding issue continues to baffle me, so i performed an expensive surgery on the mains cables to my power amps by disconnecting the ground wires. So now i am electrically grounded at the pre-amp level only. i use xlr cables throughout the system and wonder if there are any risks associated with this surgery. The sound is sensational this way with with substantial improvements particularly in bass and staging. I run 2 dedicated lines to the system installed by a professional electrician with good single-point grounding etc. So how come I have this much improvement in the sound. Baffling.
Cabling. Transparent opus. Amplification: Ayre

 

[bonzo75]

At least in the UK people suggested this is a dangerous thing to do as if one of the components that isn't grounded suffers a fault, you can get electrocuted if you are touching it. You are safe as long as you don't touch and the chained grounding through the preamp is working faultlessly

 

[Purite Audio]

At least in the UK people suggested this is a dangerous thing to do as if one of the components that isn't grounded suffers a fault, you can get electrocuted if you are touching it. You are safe as long as you don't touch and the chained grounding through the preamp is working faultlessly

I agree lifting the mains earth is madness, you are either imagining any difference or your equipment is heroically badly designed and not fit for purpose.
Keith.

 

[bonzo75]

I agree lifting the mains earth is madness, you are either imagining any difference or your equipment is heroically badly designed and not fit for purpose.
Keith.

Well I am quite sure it will make a difference, but I personally would not take chances and look elsewhere, like adding shun mooks or changing valves, cartridge etc. Plenty of safe tweaks, no need for risky tweaks

 

[Purite Audio]

Well I am quite sure it will make a difference, but I personally would not take chances and look elsewhere, like adding shun mooks or changing valves, cartridge etc. Plenty of safe tweaks, no need for risky tweaks

If you suffer from ground loop hum you just have to painstakingly work through and discover the proble, lifting the earth is dumb.
Keith.

 

[Speedskater]

Well designed XLR balanced interconnect systems a very immune to hum problems.
So maybe a poorly designed or defective component or cable.
Does everything pass the John Windt 'Hummer Test' ?

 

[DaveC]

If you have two lines feeding your system then your components are on two different grounds, connected at the panel the lines are run from. This creates more potential difference and more SCIN, shield current induced noise. By lifting grounds now your entire system is running on whatever ground your preamp is plugged into, which is much better from a grounding perspective but not from a safety perspective.

The best solution is to plug your entire system into a single power distribution block with all the grounds in that block tied together at one point, this block should be plugged into one outlet. If you really need two lines (unlikely) then you should have two power distribution blocks as described, with their grounds tied together using a heavy gauge (12g+) wire.

This will solve your ground issues and make your system sound the way it is now, but will not be dangerous. Right now your components are grounded through your IC cables... IC cables are not designed to carry fault current!

 

[ack]

More than that, the interconnects may melt and/or catch fire, and if the preamp "floats" signal ground from chassis ground, there is risk of sending spike current to its signal board, potentially damaging it. Star-grounding at the power-strip is the safest approach, over star-grounding at the preamp.

 

[DaveC]

There's also liability issues. If this hurts someone you're directly responsible because removing safety grounds is negligent, if someone gets electrocuted you'll be paying their family for the rest of your life. Your insurance also won't pay for any damage it might cause if it sets your house on fire. There are significant risks involved in doing dangerous things like this.

 

[mcduman]

I sort of expected that this is not the smartest thing to do. But Charles Hansen of Ayre is such a vocal proponent of floating that l could not not try this. And I thought xlr cables could somehow could handle fault current

 

[ack]

XLR cables are nothing but three thin wires, not large enough gauge. So Hansen is a proponent of floating the amps ground? That would imply the amps are prone to any ground-induced noise, not just hum.

 

[mcduman]

http://www.audioasylum.com/audio/speakers/messages/198058.html

 

[Speedskater]

In an XLR balanced analog interconnect system, the shield is not required to be connected at the receive end.

 

[ack]

http://www.audioasylum.com/audio/speakers/messages/198058.html

The reality is that I float everything but the preamp, and thus star-ground to the preamp, for the very *slight* sonic benefit over star-grounding to the power strip (even when using same-length and brand/model cords), and the benefit is real albeit small (i.e. I don't hear improvement to the same magnitude that you do), and it has to do with noise in the line (not hum).

But I did it based on my knowledge and after various discussions with manufacturers of my equipment and dealers, not based on internet posts, and with the understanding that the danger is there. Therefore, I am comfortable with the potential consequences, though I don't really recommend that to anyone else, because people will not spend the time to analyze risks vs benefit, nor do they understand their own equipments' design.

I would encourage you to talk to Ayre now about their newer products, as opposed to relying on something written 10 years ago. Hansen's argument that the Japanese use only two-prong cords is a little weak (though true) because it does not paint the entire picture as we have, and he's not specifically talking about amps using two-pronged cords.

The question for you is, if you properly star-ground to the power strip, will you then hear additional improvement if you star-ground to the preamp? And if you do, I doubt it will be to the same degree as you originally described it.

 

[mcduman]

thanks. i had 2 humongous tubed mono power amps at the time and the common wisdom then was to run 2 dedicated lines rather than 1. the lines are identical and meet at the panel level but i see how this can be the source of my problem. i will try as suggested and report back.

 

[mcduman]

The reality is that I float everything but the preamp, and thus star-ground to the preamp, for the very *slight* sonic benefit over star-grounding to the power strip (even when using same-length and brand/model cords), and the benefit is real albeit small (i.e. I don't hear improvement to the same magnitude that you do), and it has to do with noise in the line (not hum).

But I did it based on my knowledge and after various discussions with manufacturers of my equipment and dealers, not based on internet posts, and with the understanding that the danger is there. Therefore, I am comfortable with the potential consequences, though I don't really recommend that to anyone else, because people will not spend the time to analyze risks vs benefit, nor do they understand their own equipments' design.

I would encourage you to talk to Ayre now about their newer products, as opposed to relying on something written 10 years ago. Hansen's argument that the Japanese use only two-prong cords is a little weak (though true) because it does not paint the entire picture as we have, and he's not specifically talking about amps using two-pronged cords.

The question for you is, if you properly star-ground to the power strip, will you then hear additional improvement if you star-ground to the preamp? And if you do, I doubt it will be to the same degree as you originally described it.

ack, did you also try floating the pre? i was curious to know what we are all missing

 

[amirm]

http://www.audioasylum.com/audio/speakers/messages/198058.html

That is a somewhat reasonable post from him except for this: "Finally, someone would have to touch the live chassis while simultaneously touching a grounded object (such as a cold water pipe)."

I have gotten really serious electric shocks by touching mains while not holding on to anything metal. Even through shoes and such there is low enough impedance to induce potentially fatal currents to kill you. The scenario of a cold water pipe means instant death if you didn't let go (which is hard to impossible to do). That doesn't mean the reverse, i.e. not having direct connection to the ground is just peachy. It takes in the order of milliamps to do serious damage so you could have a high impedance path to the ground and still get shocked.

Otherwise, he is right. Your odds are getting hurt or killed are small. They are the same of having an accident but I still wear my seat belts.

 

[ack]

ack, did you also try floating the pre? i was curious to know what we are all missing

No, can't do that, we need a real ground somewhere. This is fundamentally the same as star-grounding at the power strip, where the strip's power cord is the one that eventually connects to the real ground. If you are concerned about noise seeping into the preamp's ground, you'd be right to do so, but... in this case, my preamp floats signal ground from chassis ground which should reduce any such noise (notice, this doesn't mean the two grounds are totally decoupled; floating still involves coupling them with something like a resistor, capacitor, or something else in between - proper floating is a mini art in itself)

 

[DaveC]

That is a somewhat reasonable post from him except for this: "Finally, someone would have to touch the live chassis while simultaneously touching a grounded object (such as a cold water pipe)."

I have gotten really serious electric shocks by touching mains while not holding on to anything metal. Even through shoes and such there is low enough impedance to induce potentially fatal currents to kill you. The scenario of a cold water pipe means instant death if you didn't let go (which is hard to impossible to do). That doesn't mean the reverse, i.e. not having direct connection to the ground is just peachy. It takes in the order of milliamps to do serious damage so you could have a high impedance path to the ground and still get shocked.

Otherwise, he is right. Your odds are getting hurt or killed are small. They are the same of having an accident but I still wear my seat belts.

Yeah, it's a small chance but the risks just aren't worth taking since the noise induced by connecting our systems to safety ground can be minimized to the point it's inconsequential, but often we do not connect our systems to safety ground in such a way. Running multiple lines from a service entrance far away from the audio system is very common. I do think the ground-box folks and Shunyata, using piezoelectric ground filtering, have found a way to help but so can paralleling a cap and a resistor between chassis/signal ground and house ground. The resistor is small value (10-20R) so the breaker still functions as intended. There's also the Schurter DINO ground choke which could be in series with the paralleled cap/resistor, it has a very low DCR.

But like insurance, you have to take it if the consequences are not tolerable. For me, the death of a friend or loved one due to my need to have a .001% better sounding audio system is not tolerable so I use safety ground.

As far as floating all but one component this can be done safely but requires knowing how your components and IC cables are built, and usually this is not adequate... but you could run your own safety ground system which would be a lot like the grounding box systems in order to be sure you have sufficient gauge for the safety ground to work as intended. IMO, the improvement vs grounding at the power distribution block is questionable, but it might help...

 

[DonH50]

That third prong is called "safety ground" for a reason... I have bypassed it but usually only for test purposes, then figured out a more permanent solution. There are a number of alternatives schemes for grounding so I would not compromise safety in the end.