AC Filtering, Grounding Boxes, Linear PSU and Balanced Power.

[YashN]

From a thread which rapidly devolved on diyaudio, but referencing another one on Audiogon:

 

"The Entreq Silver Tellus is a wooden box, the size and weight of a small power amp. It contains inert minerals and a grounding plate."

[YashN]

One more thing to note about the Entreq Silver Tellus and products in its line:

 

Once you disconnect the device, you need it to go through its cycles again to maximise the effect, which presumably occurs in audible stages, like 30 mins, 4 hours, 48 hours (the number are just examples here).

 

I forgot in which forum I read that, but it was probably the related thread at WBF.

[YashN]

Here's another thought:

 

Before Speedskater's post about dealing with chassis grounding to clean up the signal, I was viewing these two as completely separate things. That's because the original devices from Tripoint and Entreq specifically were built and recommended for these two things.

 

Furthermore, some users report that they benefit from using both of these (I believe the handle of such a user at WBF is LL21 or something like that - others are in Asia).

 

Now, if indeed we can chassis ground and clean up the signal thanks to our ground lead across all the components, what is the addition of an Entreq box with leads connecting to a free RCA shield actually doing?

 

How does it manage to further clean up the signal? And if it really does that, what is it removing?

[YashN]

If any of these boxes don't contain a block of copper or aluminum or steel or similar

 

The existence of plates of some sort in both is already established.

 

then the only thing that the box is doing is draining your money.

 

Not mine, I haven't bought any of those.

 

And all the connection points/terminals need to have a near zero Ohm resistance from one to another.

 

Could impedance matching be the important thing happening here?

[YashN]

Because different manufactures connect RCA jacks to the chassis in many different ways, we can't be sure just what is happening!

(an RCA jack is a chassis connector)

 

Exactly. I believe this could explain why several people do get the benefits.

 

Now, yesterday, after trying to get a handle on the comprehension, I just decided to go ahead and try it. I re-used parts from a failed DIY interconnect (too rigid, breaking connections, too thick a jack), to connect one RCA shield from the amp to the DAC's Coax output shield through a common copper tube. The actual cable is solid core, with an unused braided shield around.

 

We're flabbergasted we can extract additional micro-details from the already great-sounding system from two night ago. Much larger sense of space again, on Elvis - Fever, you can hear him fidgeting with jewelry or other metallic objects. On OP8 - Leather, his breathing and lips smacking. On Zhao Cong - Moonlight on Spring River, the soundstage is huge, cinema-huge, I can better hear the harmonics on the string attacks.

 

Some 20 years ago, Neil Muncy wrote a paper on the correct way to install any and all chassis connectors. That paper is referred to as the "Pin 1 Problem" paper. But in hi-fi equipment it common to see incorrect RCA jack connections (even see some incorrect XLR jack connections). So we would have to examine on a case-to-case basis to see what they did.

 

Came across it a couple of times, Brown also references this, but mostly skimmed, so will need to read Muncy a little deeper when I get the time.

 

I'm not at all sure that it cleans up the signal. Because in some incorrectly wired RCA jacks, this Entreq lead can act as a great interference antenna. So with this small amount of added background noise the audiophile will hear a real difference. This small background noise is sometimes perceived as added definition or sparkle. And because he just added something, it will be deemed good.

 

I've seen someone mention 'a friend' saying that on a forum and the explanation sounds a little far-fetched or is among the weirdest, but since we don't really know what's happening, I wouldn't dismiss it offhand. It would be funny if the enhancement heard is actually some euphonic coloration.

 

This said, do you think an antenna's reception improves with time? This alone makes me think it isn't the correct explanation.

 

Notice that no one would ever put a battery powered O-scope or meter on the speaker terminals and examine the changes.

 

Could be helpful.

[YashN]

Has the connector to connector resistance ever been measured?

 

I don't think have come across these measurements in the forum posts.

[YashN]

I use a Granite Audio Ground Zero device for my chasis ground plane, this cleared up noise due to my system's mixture of balanced / unbalanced connections as well as tube / SS devices. Getting to chassis ground can sometimes be a PITA. As an example, my amps have an aluninum casing, therefore I had to open them up to connect to the chassis and then figure out a way to route the wire out.

 

I'm not sure how much better one mixture a grounding materials is over another (back to the dragons) but I can say, from personal experience, that going from nothing (i.e. the way components are connected straight out of the box) to something makes an audible difference - lower noise floor, clearer instruments, and decays that fade off into space (i.e. a bell strike).

 

Thanks for pointing this product out, Jabs, and for sharing your experience as well. I had read about it a few days ago, but forgot to post about it.

 

 

Some interesting info about how this completely passive device works from the website:

 

Ground loop problems generally begin when there is a difference in the ground potentials of the various components in a system. The ground potential of one component may be higher or lower than that of another connected component and the component's ground path to earth ground, or ground impedance, may be higher or lower than that of the other connected component. The result of a ground loop is audible hum, usually 60 cycle, that sounds like a low bass rumble. The noise can be extremely objectionable if it can be heard over the music or during quiet passages. Since the noise is low frequency, it also robs your system of available dynamic power because the amps are wasting their resources by amplifying this audible signal. An audible ground loop robs system power.

 

These unbalanced components share a common ground bond between them via the shields of their interconnect cables, or via the ground wire of their AC power cords. The ground bond created by the interconnect shields is problematic because of the small gauge of the wires, dirty contact surfaces, and the sometimes low mechanical integrity of the outer grounding ring of cheaper RCA plugs. If your RCA plugs have a lose fit, you have a potential grounding problem.

 

The ground bond via the AC power cords can be problematic because the cords may be different gauges, have different contact mechanical integrity at the outlet, and have different distances to travel back to earth ground. All these variables can create differences in the ground impedance of each component and opens the door for ground loops and system noise.

 

 

How GROUND ZERO works:

This is where GROUND ZERO does it's work. It functions totally in the ground circuit, so there's no interference with the music signal path. GROUND ZERO first bonds all the components together in a central star location with identical wires & terminations. The wires are all of the same large gauge and ultra-pure OFC flexible copper for identical low-impedance ground paths. Then all the terminations are gold plated and soldered to the copper wires for low impedance and long life integrity. The chassis banana jacks are one-piece construction and internal wires are also heavy gauge & soldered. The toggle impedance balancing switches are the most expensive parts in GROUND ZERO . These switches are ultra-low impedance, less than 5 milliohms, and have silver contacts rated at an impressive 32 amps per switch for long life integrity. So, GROUND ZERO presents a super high integrity, and uniform ultra-low impedance matching system for your components.

 

Any 2 components connected to the same color banana jacks will always have their GROUND ZERO cables at the same impedance, regardless of the position of any of the toggle switches. So, components connected to the same color jacks are bonded to each other at the jack itself at the lowest possible impedance, and this will not change with changes in switch positions.

 

Components that are connected to different colored jacks have their GROUND ZERO cables isolated by the corresponding toggle switches. This feature allows the user to match and balance the different ground impedances of each section to each other section. Each toggle switch has 3 positions it can be set to. High, Low, or Medium Impedance. These settings determine the ground impedance bond between the 3 sections. With 3 sections, 3 switch positions, and the possibility to plug components into different sections; there are a minimum of 27 different impedance matching settings. Because of the basic design of GROUND ZERO , many different settings will actually yield the same noise floor readings on a decibel meter. But, one or more different settings will give the lowest audible & measurable noise floor. So, relax, there's not 26 wrong settings and only 1 needle in the haystack. Depending on your system, you will probably find that you will get 3 to 5 different results. A result is a difference in the audible or measurable noise.

[YashN]

Also static buildup before the storm. At the broadcast transmitter, we would see huge arcs across the tower insulators hours before the storm.

 

This reminds me that I have seen a few people talking about removing static electricity every couple of days from terminals (Speakers) to get better sound.

[YashN]

The related page at Core Audio Technologies about Grounding has a lot of interesting information.

 

 

Examining Cable designs

 

 

1. Not all balanced cables are designed properly! Many shield currents in balanced cables are shared by internal component circuitry. The shield is connected to circuit grounds. Common impedance coupling turns shield connections into low impedance signal inputs. This “defect” is designed to an alarming amount of audio products. The problem exists at I/O ports in any piece of equipment where the shield current is allowed to flow in PCB traces shared by internal circuitry. Ever see an RCA ground connected to ground on the PCB via shield… I see it all the time.
   

 

 

1. Electric field shielding
   


1. Capacitive coupling happens when there’s an air space between conductors
   
2. Larger surface area also causes increase in capacitance
   
3. AC voltage causes AC current to flow through this coupling effect
   
4. Shielding a cable only at the receiving end creates an uneven pair of low-pass filters for common mode noise, this is bad because the mismatch converts CMN into differential mode signal, which degrades performance at high frequencies.
   
5. A shield should be grounded ONLY at the source to eliminate the LPF effect.
   
6. At higher frequencies, grounding at one end isn’t effective enough as these high noise frequencies get induced back into the signal quickly.
   

 

[*]Magnetic Field Shielding

1. Magnetic alloys or steel conduit must be used to shield from 60hz magnetic fields.
   
2. In AC Wiring twisted or parallel wiring provides near-perfect cancellation unless you are very close to the wire. BUT
   
3. Shield current induced noise – current in a cable shield creates a magnetic field extremely close to the twisted pair inside. This results in unequal induced voltages that add to the signal.
   
4. The worst cables use a drain wire, which distorts the magnetic field and hogs the shield current.
   
5. For low level signals a drain wire should never be used or connected only at one end so that no current flows through the shield.
   

 

[*]Hybrid Shield Grounding

1. A conundrum!
   

    

   [*]Enter hybrid grounding – this uses a capacitor at the receiving end of the cable to ground at high frequencies, while allowing better CMRR at the source end. Basically use a capacitor at the receiving end and connect the shield directly at the source end.

   [*]Complexities: The capacitor must be constructed and connected in a way that makes it effective over 1GHZ – this is not trivial. To be effective over a few mhz the capacitor leads must be extremely short.

   1. My recommendation would be to use a .1uF, .01uF, 1000pF cap in parallel, but in series with the shield – of course the cap you choose is important as is the lead length. And no, audiophile caps are not the best solution here.
      

    

    

   Grounding tweaks and advanced grounding and shielding

    

    

   1. The first tweak is likely the easiest. Some systems it hurts more than helps, others it helps tremendously. Try it and see where it gets you.
      
      
      
   2. Run a large awg wire from a chassis screw on each component to a single wall receptacle center screw (ground).
      
   3. The idea is to connect all components to a single ground point and allow a low-impedance path for the shields to earth. Adding a capacitor on the receiving end may improve performance at RF frequencies. If you find this creates noise or makes a ground loop worse, try connecting a capacitor.
      
   4. It’s important to do this to a single receptacle or it defeats the purpose.
      

   
   
2. Grounding at the source produces the best possible Common mode noise rejection at audio frequencies
   
3. At high frequencies, grounding the shield at the receiving end reduces RF interference.
   

[YashN]

Another good video from Core Audio Technologies, contrasting different implementations and their disadvantage:

 

[YashN]

When it's good, it's very good, but when it's bad, it's just plane awful!

 

He might say the same about your spelling

 

Why do you think so precisely?

[YashN]

Speaking of Whitlock, here's an extract of an AES tutorial by him:

[YashN]

Important slide from Whitlock's presentation:

 

[YashN]

Whitlock - Pin 1 problem:

 

[YashN]

Neil Muncy on Grounding:

 

[YashN]

Without a transcript of the video, I'll pass on getting into it.

 

Pause video + screenshots may help. Additionally, if you click on Youtube and watch it from there, there is a button you can turn on which will give you automatic subtitles (mostly accurate but not always).

[YashN]

I think I am going to start noting down in this thread what I can hear when I listen to the system with these 3 new things: 3 filter lines + chassis grounding + signal grounding.

 

I am currently listening to Peter Gabriel's 'So' and rediscovering the album. Right before that, I listened to Indochine's '7,000 Danses' (same impression of re-discovering the album, and I know these tracks very well!), some David Bowie and Billy Ocean.

 

This sounds too good.

 

Last night I put on a few tracks for us and one especially for her: she was entranced, said she knows that track very well (I do too but not that particular version), and she's heard things for the first time. Sade's Best Of album sounds totally like a new album. She hadn't even heard me come back to serve her dinner while listening to a Toto track - she said she was transported by the music

 

Percussions and drums are awesome. Very good separation of instruments. I think we can also say a darker background right before the music starts. The soundstage is big. It's going to be fun to watch a movie with that sound as well.

 

I am still not convinced by my implementation of chassis-grounding though.

 

The sound appears to be changing as well since yesterday, so I am slightly reluctant to tweak more today and let it settle.

[YashN]

This explanation by Audiogon member Davehrab on a good thread sounds sensible to me:

 

The Entreq appears to be a sink for stray voltage that is floating around on your component’s chassis and ground planes .. it might be using magnets or ceramics to provide a low impedance sink and path way for this stray voltage on the chassis to migrate to as it may be of lower impedance than the ground rod lies at ... ideally you would like your ground rod to be at 5 ohms or less but they can trend as high as 25 ohms of resistance

 

Generally the dryer the soil the higher the impedance (resistance) .. Texas, Arizona, and Nevada would come to mind ...

 

The higher the water table and moister content of the soil ... the lower the impedance due to better conduction in the moist soil

 

You can have a licensed electrician come out and preform a “Soil Resistivity” test to determine the impedance of the ground system

 

Voltage/Noise couples to the chassis and it’s ground planes and if the impedance at the ground rod is high enough the stray voltage will see the Entreq’s lower impedance and migrate down that path way

 

Electrical current has no loyalty ... it’s not very monogamous ... and will always travel down the path of least resistance as opposed to going where we intended it to travel

 

I see two factors which can contribute to the effectiveness of the Entreq and why some have success and others don’t

 

First is the impedance that your ground rod lies at .....

 

If it is equal to or lower than the Entreq sink impedance ... the stray voltage may see the ground rod as the lower impedance and migrate to it .. in which case the Enteq would seem relatively ineffective providing little to no improvement

 

How ever if the ground rod has a very high impedance due to dry conditions then the stray voltage will see the Entreq as the lower impedance and migrate to it ... in this case the Entreq will provide an audible improvement by lowering the noise floor

 

But wait a minute the ground wire is the third wire safety which is only there to provide a low impedance pathway for a fault (dead short) to travel on until the breaker trips ... it does not lie in the signal path nor is there any musical content on it ... Hmmm ???

 

It’s seems our equipment have two ground planes in them .. one is the Safety Ground for our protection and has nothing to do with the musical content and the other is the Signal Ground plane which I don’t believe is really a ground plane but the return leg for the audio signal

 

The return leg needs to be referenced to Zero volts so they tie the Signal Ground to the Equipment Safety ground for referencing assuming the safety ground was at Zero volts ... unfortunately it’s not and there is stray voltage on it and the metal chassis and because they reference or tie the signal return/ground plane to the Safety ground the stray voltage on the safety wire will loop back into the signal return/ground plane adding noise to the original signal ... besides not being loyal or monogamous electricity travels in loops and this is how the voltage (noise) travelling on the chassis and ground plane loops back into the signal and is presented as noise

 

By providing an alternate lower impedance pathway ... the stray voltage migrates to the Entreq instead of looping and coupling into the signal return/ground plan ... less stray voltage on the signal means lower noise floor

 

But wait ... there is a hitch .. some equipment have separate dedicated pathways for the Ground Safety circuit and the Signal Return/Ground plane circuit ... they are not connected or tied together so there is no way to for the stray voltage (noise) to migrate into the signal as noise riding on the line .. here the Entreq would have no effect as there is no connection between the Stray voltage floating on the chassis and ground planes and the Signal Return/ground plane

 

If your component has a separate Signal and Safety Ground plane .. like my Ayre does .. the Entreq will not help as the stray voltage can’t loop or migrate into the signal plane ... if your component has both planes tied together for reference then the Entreq can help

 

If your ground rod lies at a high impedance then the Entreq can help

 

So if your signal and ground plane are tied and your ground rod has high impedance this is where the Entreq brings the most improvement .. other combination become less effective

 

This may account for the mixed reviews and all the .. it does vs It doesn't .. because it will and it won’t .. ;-)

[YashN]

But, but, but!

That long explanation is completely incorrect.

 

You can do better than that, Speedskater...

 

Tell us precisely where and why.

[YashN]

I just looked at the thread:

 

This explanation by Audiogon member Davehrab on a good thread sounds sensible to me:

 

The only good posts came from a member 'atmosphere'.

 

The rest are a mix of mis- understanding, nonsense and fantasy.

 

That's Atmasphere, purveyors of very fine and highly-regarded tube amplifiers, and is the reason I mention the thread is good.

 

 

Here are Atmasphere's posts, emphasis mine, make total sense to me:

 

Davehrab got it right. In order to pass safety requirements the equipment must be grounded. The problem is that if the electronics are grounded, ground loops can result, which usually results in a buzz of some sort.

 

So if the designer is using good engineering practice, the circuit grounds of the equipment will not be the same as the chassis ground. However the circuit ground does benefit from the shielding of the chassis; in order for the chassis to not introduce noise, the circuit ground is set up so that it floats at the same potential as the chassis ground, even though they are isolated.

 

I have found that this is not a common practice in high end audio! But for equipment that is grounded properly by design, such grounding devices like the one this thread is about will have no effect on the gear at all.

 

Sorry to pop any bubbles, but if you are using such devices to good effect, it simply means that the manufacturer(s) of your electronics have not done their grounding homework. It quite literally is that simple.

 

Agear, having had some experience with some of the manufacturers on your list, I have to agree. Others on that list did their homework.

 

FWIW, very few if any manufacturers from the 1950s got their grounding right. I work on Ampex stuff all the time; I hate to say it but their approach was really flawed. As you look at equipment that has been made over the decades, its pretty obvious that grounding was something some manufacturers understood and others didn't. That holds true in spades today.

 

That is why some people get benefit from exotic grounding schemes and others do not. So why harp on this? Simply because if manufacturers could get there ducks in a row, their equipment would perform better without a need for an exotic ground.

 

Power cords can have plenty of measurable effects and I have talked about the physics about why on other threads. Similarly, power conditioners can really help too (although most high end audio power conditioners are so much junk- the best one ever made was made by Elgar, model 3006, which embarrasses anything offered to audiophiles). It can put out a distortion-free 60Hz sine wave at full load of 28 Amps.

 

You can sort out easily enough if the equipment is properly grounded by using a DVM. Connect one lead to the chassis and one to the center pin of the IEC connection or power cord. You should measure a short.

 

Then connect to the ground of the input and output connectors. You should not see a short- but some nominal resistance. I've seen a lot of power amps where input ground and chassis ground are the same thing. Such a unit will be sensitive to the earth ground. I've seen others where the chassis seems to float relative to the inputs. Again, there will be troubles with ground.

 

It does not matter who made it. What matters is whether its set up right.

 

And as a quick reminder, here is how I ended the original post in this thread (edited of typos):

 

During my recent readings, I was reminded of the importance of the Ground Plane in DIY Ham radio circuits. In equipment which has not been designed properly, this is not well implemented. Thus, we often find ourselves with a mix of properly and improperly designed equipment, each with their own grounding scheme, each with either a two-prong power cable or a 3-pronged one.

 

Could this be the explanation why some people report getting much better results using grounding boxes? Take for example two commercial products which are very expensive and out of my budget:

 

1. Tripoint Troy - Grounding box used for chassis grounding for all components of your playback chain. This connects through a Ground pin only to mains.

 

2. Entreq Tellus - Autonomous Grounding box initially reserved for grounding Signal returns (e.g. an RCA return from each of your components). This doesn't connect to any other ground or earth, it has its own internal ground.

 

Are our power lines, grounding schemes, power supply units compromised in various ways and greatly spoiling our enjoyment of music?

 

Thanks for the analysis on Davehrab's post, will address that later.

 

Enjoy the week-end and Happy 4th.

[YashN]

Without a transcript of the video, I'll pass on getting into it.

 

Here's the related article, Audiophile Power Cables and Power Distribution on the Core Audio Technology website.

 

An extract:

 

Resistance is the easiest to compensate for. Merely by making the cable larger we can reduce resistance in the wire. Unfortunately, a decreased resistance in the wire does very little when it comes to the other two elements: inductance and capacitance. This is also why a heavy gauge power cable won’t necessarily (and often not) sound better than one of smaller gauge and proper geometry. This isn’t to say resistance doesn’t matter, it matters within reason, but most cables are already such low resistance as to make that element somewhat obsolete.

 

Both inductance and capacitance impede transients. Inductance resists the change in current, much like a ferrite bead filters noise. The ferrite bead resists changes in current, absorbs that energy, and converts it to heat. That conversion eliminates noise in a very narrow bandwidth, but also (as I’m sure you’ve experienced) impedes transient response. So in wiring of all kinds designers do their best to reduce cable inductance because they do not want anything to impede the flow of electricity. This is why you will see LC filters used. The inductor creates a path of high impedance, which “makes” AC noise want to travel along an easier path, the capacitor. This has the unfortunate consequence of power loss as some of your power flows through the capacitor instead of to your audio system.

 

Capacitance is similar, but different. Capacitance occurs when two conductors are close together and each conductor is affected by the other’s magnetic field. This magnetic field causes the wire to store electric charges that are the OPPOSITE of what is being carried down that conductor. This is because the potentials between the wires are slightly different and this creates a similar affect to the plates in a capacitor. Any change in voltage across the wires causes a current to flow across this parasitic capacitance and energy is lost. Because this doesn’t happen instantly, the voltage is re-introduced moments later out of phase. At low frequencies this can be less of an issue until currents get higher. It is much more problematic at high frequencies where it can create oscillations. This is also why it makes no sense as to why companies use capacitors to filter AC power, it not only creates tremendous amounts of power loss, but phase distortion as well. As frequencies get higher the phase distortions get worse because of how quickly parasitic capacitances get introduced back into the wiring.

 

So in the ideal power wiring, all three inductance, capacitance, and resistance would be reduced to extremely low levels. Why is this so difficult?

 

This is extremely difficult because of magnetic fields. There are external magnetic fields, fields generated by the wire and their proximity to themselves, fields from vibration, from conductors rubbing together, fields from leakage currents from your audio equipment, and so on. These magnetic fields, depending on their source, increase both L and C in the cable.

[YashN]

You found a lot of the Core Audio nonsense!

 

Looking forward to more details and precision about that statement

[YashN]

Electrical current has no loyalty ... it’s not very monogamous ... and will always travel down the path of least resistance as opposed to going where we intended it to travel

Electrical current will travel down all available paths in it's return to it's voltage source.

 

If you want to correct his statement, might as well make yours more correct: the currents will preferentially go back to their source (most compact loop like Ott says) through the path of lowest impedance, the distribution among paths being directly proportional to each path's admittance.

[YashN]

A few must-reads by Philip Giddings, 4 & 5 are excellent, there are tables of values in some of the material which is quite worthwhile as well:

 

1. Collected papers - Power Grounding and Noise

 

2. Getting a Perspective on Noise in Audio Systems

 

3. Grounding Systems and their Implementations

 

4. Grounding and Shielding for Sound and Video

 

5. An Introduction to EMI and EMC

[YashN]

More Neil Muncy:

 

History & more videos @ Neil Muncy

 

"Star Grounds, Loop Areas, & Electrical Safety In Project Studios, Edit Suits, & Other Compact Audio Installations"

Part I, II & III

 

Thanks for those resources, the Muncy papers are hard to come by, already had the RX prescription one.

 

The Tech papers page on the first resource has a lot of Brown and Whitlock, including Pin 1 reference.

 

I figured the gist of Muncy's work showed that Balanced is better than unbalanced, but when closely analysed, many manufacturers badly implemented even the balanced interconnection or other equipment. Moreover, I read that Muncy recommended transforming all unbalanced equipment into balanced.