Component grounding


This is an Audio 101 question.

My Shunyata power conditioner has grounding posts. If one fancies supplemental grounding for one's components, beyond the ground wire in the power cord, one can run a wire from a chassis screw to the posts on the conditioner.

I’m not using the phono ground post on my integrated. Can I run a ground wire from there instead of a chassis screw?
rfprice
Yes. It’s the same ground as the chassis ground!
Then the question is, is this a good idea, or does it create a ground loop that can make the signal more subject to hum, not less?
Why do you feel you need additional grounding?
Generally speaking, modern components fall into one of two categories
  • those with grounded power cords
  • those without - i.e. two pin plugs 

For the latter, the chassis of the ungrounded components cannot be grounded and may "pickup" some EMI/RFI - therefore grounding eliminates this and may prove to be beneficial

Having said that, some components with a grounded power cable may not ground their chassis either, so they fall into the same category as ungrounded

So without testing each component its hard to tell which would benefit from additional grounding

Some people swear by chassis grounding - but I've never found it to be beneficial on any of my systems

But that's not to say it might be beneficial under certain conditions

Regards - Steve




Thanks for the helpful input. 

I introduced a 'new' integrated into my system and a hum appeared. In fact, I had owned this same model integrated about 10 years ago and seem to recall a hum at that time too. My tech friends assert that there are no technical defects, just something peculiar about the components' interaction. The hum goes away when I plug the amp into the second receptacle of the wall outlet, or when I use a cheater plug to connect it to the Shunyata. 

Ultimately I modified a power cord, disconnecting the ground wire. That took care of the hum, but then I began to worry that the amp was now ungrounded. So I installed a wire between the phono ground post and the grounding posts on the Shunyata. Maybe it's not necessary. 
@rfprice - that hum is probably due to the unit having a two pin plug OR being ungrounded.

This is common and easily remedied...
  1. try connecting a piece of wire to the ground point on the power conditioner
  2. then touch the other end to any unused RCA socket on your amp
  3. the hum should disappear.
If it works you can make up a grounding lead as a more permanent solution using any old RCA plug, but connect to the neutral side of the RCA only

My NAIM amp was designed in such a way that it relies on the source components being grounded. So if the source had a two pin plug it would cause a hum

Hope that helps - Steve
@williewonka -- Thanks, Steve, I'll try that. The amp has a three-prong connection. Defeating the ground prong with the cheater plug made the hum go away.

Something funny happened yesterday. The integrated has a function that allows you to bypass the preamp section and use the output control on the source component instead (the DAC, in this case). I tried that for the first time yesterday and the hum came back. When I reengaged the preamp section, the hum went away again. 
@rfprice - you should NEVER defeat the ground on any component !!!

It is there for a reason - SAFETY !

I know its a common solution, but you are not addressing the root cause of the problem

Regards
@williewonka  -- Yes I know it's not an ideal solution.

I will try your suggestion to run the wire to the RCA terminal. 
The hum goes away when I plug the amp into the second receptacle of the wall outlet, or when I use a cheater plug to connect it to the Shunyata.
This is caused by something called a ’ground loop’. Its generally a sign that some part of the system is inappropriately grounded. I’m not talking about the power cord and its ground connection nor the use of a grounding post (which I think you’ll find won’t help).


I’m talking about the way a component is internally grounded. How it should work is if there is a metal chassis, it should be grounded thru the power cord. But if the audio circuit inside is directly grounded to the chassis it leaves the circuit open to ground loops. To avoid this, none of the audio circuit should be tied to chassis, instead an impedance of some sort (a resistor perhaps) should go between the two, allowing the audio circuit to float at ground potential (this is the reason why RCA connectors have insulating shoulder washers to insulate them from the chassis, even though the barrel connection is 'ground'). The resistor should be high enough resistance (if a resistor is used) to prevent the ground loop.


I’ve really boiled this down; grounding can be a very complex issue!


If you own a component that has a poor internal grounding scheme (IOW its use causes a ground loop in your system) you can get around the problem by use of an isolation transformer between the AC outlet and the component. Its not the best solution (you have to get a big enough transformer) but it does work. I prefer to have the grounding of the components set up properly to begin with...

@williewonka  -- I tried the RCA terminal solution but it had no effect. 

 

@atmasphere  -- Thanks for this. You're right, it's complicated. (You are also right that the grounding post made no difference.)

 

I'm starting to wonder if the problem has more to do with the DAC. As I wrote above, when I disengaged the preamp section of the amplifier to control the volume with the DAC output control, the hum came back, even though I was still using the modified power cord on the amp. But then again, this didn't happen with two other amps I had on hand. 

@rfprice 

Hm. That kind of suggests an isssue with the amp. Have you tried other amps when the preamp is in the system?

@rfprice - What happens if you take the Shunyata Power Condtioner out of the system altogether?

What components do you have?

Thanks

@atmasphere  -- No no, I meant the preamp section of the integrated. It has a feature that let's you bypass the preamp section and use the output control on the DAC instead. When I did this, the hum came back. I don't know what that means, but you're right, the issue must reside with this particular amp because I've never had a hum otherwise. 

@williewonka  -- Exactly. When I unplugged the amp from the Shunyata (using the non-modified power cord) and plugged it into the free receptacle on the wall duplex (the Shunyata occupying the other receptacle) the hum disappeared. So that would suggest . . . what? That the isolated zones on the Shunyata are not so isolated after all? 

The neutral side of any circuit should be at zero volts, but very often the neutral side may have some residual voltage due to the design of the circuit. If this voltage is not "wicked away" to a proper ground then connecting that component to another component may introduce hum.

In your case it would appear that the neutral of one of the components plugged into the shunyata is not at zero volts and the "isolated zones" on the shunyata are doing a great job at isolation (even the ground), but this allows the component with the non zero neutral to propogate the hum via the interconencts.

Can you plug everything into a single Zone?

Or perhaps experiment with different groupings of components in each zone e.g.

- pre-amp and source in one zone power amp in another

Try different permutations to see what works

Hope that helps - Steve

 

.

This got me thinking. Several months ago I opened the DAC to try a specialty fuse. To free the cover, you have to disconnect the chassis ground.

 

--As I wrote earlier, when I disengaged the preamp section on the integrated and engaged the output control on the DAC, the hum came back. Also, over the last few weeks as I've been trying different combinations in order to try to identify the culprit, I noticed that the hum kicked in when I connected the interconnects from the DAC to the integrated. It didn't happen when the components were merely plugged in and powered on. (Although this still doesn't explain why the hum didn't happen with either of the other two integrateds that I tried.) --

 

Anyway, this morning I decided to open the DAC again to check whether I reattached the ground chassis correctly. I discovered that there was no shoulder washer. Whether I lost it or it was never there, who knows. So I installed a nylon washer and powered up again. 

 

No difference. Still a hum. 

I also tried connecting the integrated and DAC to a single zone. No difference. 

 

So perhaps the integrated has a bad chassis ground? 

@rfprice - obviously there is some pretty strange grounding issues at play here and without being there it is difficult to advise on a solution

RE:..

I noticed that the hum kicked in when I connected the interconnects from the DAC to the integrated. It didn’t happen when the components were merely plugged in and powered on.

This indicates to me that the DAC is causing the issue not the integrated

- did you try grounding the neutral side of the output from the DAC as I suggested above??? i.e.

  1. try connecting a piece of wire to the ground point on the power conditioner
  2. Also try the ground point on an outlet
  3. then touch the other end to THE NEUTRAL COLLAR ONLY of any unused RCA socket on your amp
  4. the hum should disappear.

 

(Although this still doesn’t explain why the hum didn’t happen with either of the other two integrateds that I tried.) --

This is because the other two integraed amps had a different grounding scheme

 

You say it only hums if you bypass the pre section of the integrated

- wih both DAC and itegrated plugged into the shunyata in any combination

- but IT DOES NOT HUM if the integrated is plugged into the wall outlet

- and IT DOES NOT HUM if the pre section is NOT bypassed

So I think you have one of two possible solutions/choices.

Personally, I have ONLY EVER plugged my intergated or amp directly into the wall outlet - it allows the amp to excercise if full dynamic prowess.

I no longer use a power conditioner of any type, just a power distribution box with no "isolatoin" or filtering, but I do have a device like the Shunyata Venom Line Defender to protect the gear from surges - I also have a surge supressor on my electrical panel

Sorry I could not be of more assistance

Regards - Steve

 

@williewonka -- Thanks for all your advice thus far. It's much appreciated.

 

The neutral collar is the outer metallic 'shield', correct? If so, I did run a wire from the ground post on the Shunyata to the collar of an RCA of the integrated. No effect. You mention a similar operation with the DAC? 

 

You're right that it would make the most sense to just connect the integrated to the wall. But I like what the Shunyata does for the integrated. It doesn't suck a lot of juice so I don't think I'm losing much in terms of power. The other components are just a DAC and transport, so the Shunyata is not taxed. 

No no, I meant the preamp section of the integrated. It has a feature that let's you bypass the preamp section and use the output control on the DAC instead. When I did this, the hum came back. I don't know what that means, but you're right, the issue must reside with this particular amp because I've never had a hum otherwise. 

 

That sounds like a problem with the DAC. So if the amplifier is using its internal preamp, no hum, but if you connect the DAC to one of the inputs and use the preamp section's volume control- you have a hum (or buzz), right?

If yes it suggests an issue with the DAC. Since you did something to it as suggested in the posts above, it might be that there's more to it than a missing shoulder washer.

@atmasphere -- That's starting to seem to me like a likely explanation also. Plus the fact that the hum begins when the interconnects are inserted, not when everything is simply powered on. But I really didn't do anything to the DAC except switch the fuse. I'm very careful when doing any kind of operation with my equipment, and as I said earlier, there is no hum with the other two integrateds. One is a solid state, the other a tube.

 

I installed the nylon washer between the chassis and the ground wire ring. Then a ground washer screws against the ring. Is it worth trying another nylong washer between the ring and the ground washer? 

I installed the nylon washer between the chassis and the ground wire ring.

That doesn't sound right! If there is a connection to the chassis (and I'm assuming it comes from the center pin of the IEC connector) it would not be insulated from the chassis by a nylon washer!

Am I misunderstanding?

 

I wish I could post a photo of what I mean. If you follow this link to page 7, it talks about a ground wire running from a grounding block on the floor of the chassis to a screw on the side of the top cover. Before you can do anything internally, you have to disconnect this wire from cover; otherwise you can't get the cover out of your way. So, what I did, I put a nylon washer between this wire (which has a ring termination) and the chassis. Then a ground washer goes onto the end to screw it all down. Does that make sense? 

OK, I can't post the link. Anyway, it doesn't say more than I just said. 

I installed the nylon washer between the chassis and the ground wire ring.

Perhaps the wire should be next to the chassis and the nylon washer placed on top of it - and not in between the wire and the chassis?

I am assuming it is a metal screw?

Seems strange to put a piece of nylon (an insulator) between the chassis and the ground wire - but I guess the screw should make the connection

What DAC is it??? - so we can look at the manual

Regards - Steve

 

Post removed 
Post removed 

Why is there no grounding standard for electronics?

There is. What there is not is a standard for what every person buys and hooks together in their system.

It’s a pity that I couldn’t post a drawing of best grounding technics (something didn’t work here). I will try to explain it as best I can.

There are 3  “grounds” that need to be connected correctly in order to make sure that potential differences between audio equipment don’t chose the path through the circuit which will become  audible as  hum or buzz : the ground for the audio signal on the circuit board or star ground if point-to-point wired (let’s call it reference ground), the power supply ground which of course needs to be clean (normally is with HighEnd gear),  and the ground which connects each piece of equipment (shield ground). If these 3 grounds are connected in the right way and grounded to Earth there will be no audible ground loops. I will only talk about SE (RCA) grounding for simplicity sake because that’s also what most people have.

If we look at a single unit it doesn’t matter how the “grounds” are connected together and the electrical standards/code is only concerned about correct  grounding to Earth for safety reason. So the manufacturer can do everything right and the buyer can still run into ground loop problems (more or less audible but it will always create IMD and impact SQ). If we connect two or more devices together, different ways of grounding in each unit and potential differences between “reference grounds” can create audible ground loops. We must make sure that the path for the current caused by potential difference will always go directly to Earth and not through the audio circuit where it becomes audible as hum or buzz.

So how to connect these 3 grounds then? Unfortunately we would need to open each device and find out how it has been grounded. Ideally the ground of the power supply (which is  ground for the circuit board or connected to star ground in tube gear) should be also connected directly to shield ground (ground from RCA connector) and chassis ground (if that was part of the original ground) in one single spot which is then connected to Earth ground (via ground of the power cable). All power cables should be as close as possible together in one power strip/conditioner. Shield ground and power supply ground stay of course connected to the circuit board as it was in the original circuit. But now the difference is that potential differences between audio equipment will take a short cut to earth ground instead of running through the circuit. Only one extra cable from psu ground (power common) would need to be added. Don’t know if that can be done without losing the warranty? Cheater plugs and open Earth ground  can help but never remove ground loops hundred percent and are unsafe.

Another issue is if power conditioners use different grounds between their power outlets. I use a Furman IT 20 Reference for analog (prefer the sound with balanced mains power) and a Power Plant for digital. Both systems are totally separated (otherwise the different grounds have some audible influence) and I switch only the speaker connection.  If there are still ground loops with the above grounding scheme a separate grounding cable (power cable grounding needs to stay as is for safety!) to the ground of the other receptacle can do the trick and stop the ground loop.

I know that might sound a bit overwhelming at first but it resolves all the problems with ground loops and helps to improve the SQ quite a bit (more clarity and subtle details). I hope it is helpful.