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

[Duke40]

Forrest, I never took your comments as anything but helpful.

 

I am also grateful for your last post, that certainly helps me, so I thank you again.

I genuinely appreciate it.

 

John

[YashN]

To avoid cross contamination between components is not that simple, since an audio component will provide a different spectrum. The injection mains side spectrum from an amplifier is different to a CD player or computer, so the filter should be tuned individually. You can add standard EMC filters PLUS use the balanced supply, since the filters work better on a symmetrical supply, rather than one side grounded if you still wanted to keep the filters.

The balanced transformer does a great job of providing an effective cross pollution from other components on its own. Having several filters in parallel could cause a surprise in that there could be a resonance condition, but not likely.

 

Hi One and a half,

 

and thanks for the excellent info about Balanced Power and Iso transformers. I have read a few of your AC conditioner related posts in past threads, thoroughly interesting as well.

 

I probably cannot take on a balanced power project currently, but the AC filter is coming along nicely: there are a few different configurations in different lines that I can use to test a single component and see what happens.

 

Totally agree with having to tune the filter lines according to the type of component. For the amp, which is high-current, a lower number of turns in the common-mode choke is good, right? The possible reduction in dynamics with improper values is definitely a concern here.

 

Then, I guess that for the troublesome digital components (I am considering the iMac, and the router, the Wi->Fi router, the HDD in those), I would need more aggressive filtering as these components' PSUs inject a lot back into the mains.

 

Now, one question that arose today was that I remember the focus on Ground plane noise, from John Swenson's posts and other reads. But, in my filter arrangements, the outlet GNDs are all connected together, there is only some filtering at the inlet, where E-L-N have a cap between each couple of leads.

 

Thus, I am wondering if there's a necessary enhancement for GND line filtering that I should add here. Otherwise, it appears to me that ground plane noise from one component can still go from one component to another one (there's no such direct connection at outlets for L-N from one component to L-N to another component).

 

Furthermore, if I do add some filtering on the GND lines, am not impacting the impedance of the ground line, especially at higher frequencies where the noisy currents are?

 

Here is the link to an schem of Jon Risch's original AC filter line.

[YashN]

Initially, Lukasz, of Lampizator fame tested Risch's design, and posted some of his impressions and revisions over at Audio Asylum. I think he posted a couple of revisions but which, overall were quite close to Jon's schematics.

 

However, the last design by Lukasz, as posted in the Lampizator archive section is quite different:

 

 

On this one, there is an inductor on the Ground lead, and coming from the inlet, the caps between Ground and L and N are after the inductor.

 

Additionally, the L2 and L3 ferrite rods are omitted for the amp outlet.

 

Lukasz mentioned on AA around 2000 that he had some great feedback on his latest filter incarnation. Whether this is the same as the 'last design' above isn't known, but his filter appears better than what I am doing currently, which seems a hybrid closer to Jon's design.

[Speedskater]

'YashN' you do not want an inductor nor a switch in the Safety Ground/Protective Earth conductor. Some experts write that capacitors from the Hot & Neutral to the SG/PE are not the best of ideas, as the caps just dump noise on to the SG/PE.

 

To get real information on power line filters, you might look to the Henry W. Ott 850 page book "Electromagnetic Compatibility Engineering".

EMC Books

 

An on-line search just might come up with a lot of Chapter 13.

 

13. Conducted Emissions

 

13.1 Power Line Impedance

13.1.1 Line Impedance Stabilization Network

13.2 Switched-Mode Power Supplies

13.2.1 Common-Mode Emissions

13.2.2 Differential-Mode Emissions

13.2.3 DC-To-DC Converters

13.2.4 Rectifier Diode Noise

13.3 Power-Line Filters

13.3.1 Common-Mode Filtering

13.3.2 Differential-Mode Filtering

13.3.3 Leakage Inductance

13.3.4 Filter Mounting

13.3.5 Power Supplies With Integral Power-Line Filters

13.3.6 High-Frequency Noise

13.4 Primary-to-Secondary Common-Mode Coupling

13.5 Frequency Dithering

13.6 Power Supply Instability

13.7 Magnetic Field Emissions

13.8 Variable Speed Motor Drives

13.9 Harmonic Suppression

13.9.1 Inductive Input Filters

13.9.2 Active Power Factor Correction

13.9.3 AC Line Reactors

[YashN]

@ YashN ...Will check out Rasmussen (at least he is local, believe Sydney based) though I believe he focus on clocks for the Oppo (which is another current interest of mine, still trying to work out if it is worth it). He seems a bit more expensive, though his modded oppo's do seem to get snapped up very quickly on the local market.

 

Rasmussen has a lot of knowledge and mods and construction. Another thread you might be interesting in over that forum, but which is off-topic for this one is about the 'Rasmussen effect'. Generated some controversy and sidelining as usual, but Coris and another member who tried it with their DACs reported great results. Never got to try that myself.

[YashN]

'YashN' you do not want an inductor nor a switch in the Safety Ground/Protective Earth conductor. Some experts write that capacitors from the Hot & Neutral to the SG/PE are not the best of ideas, as the caps just dump noise on to the SG/PE.

 

There is neither an inductor nor a switch on the ground line in my current build. I don't plan to integrate the latter either - I think Lukasz thought it a good way at the time to easily prevent ground loops if hums occur, but if I had to put a switch it would never be on that line...

 

As for the caps from L, N to G (or H, N to SG/PE so long as we understand each other), I think the dumping of noise is precisely the goal, but solely for high frequency noise.

 

So I believe the diversion to ground is deliberate, but that's also why I was asking earlier about how to properly implement the inter-component contamination isolation as currently, there doesn't seem to be anything to prevent the noise along the GND line from one component from going to the next one.

 

How would you do it?

 

Managed to do some additional building and testing tonight - see below - including a very controversial finding (for many).

 

To get real information on power line filters, you might look to the Henry W. Ott 850 page book "Electromagnetic Compatibility Engineering".

EMC Books

 

Thanks for the reference info, speedskater. I have Ott, Brown/Muncy lined up for further reading/research and already watched two of Armstrong's videos on Youtube, the earlier ones have bad sound, but the content is useful.

[YashN]

During this week-end, before testing a single filter line with the iMac, we had decided to up-convert (AIFF to DS128) Lionel Richie's Greatest Hits collection to listen to it and also test. 'All Night Long' is a great test track for percussions and rhythms.

 

The thought of testing up-conversion with the same tracks but with the AC filter connected occurred to me (not unlike sandyk's recurrent urging to rip with linear PSUs for better sound).

 

Didn't think much about it until this afternoon when I tried to finalise the two other duplexes (only 3 filter lines connected for now although all 3 duplexes are separated into 2 outlets each).

 

So I up-converted 'All Night Long' and 'Say You Say Me' again, with only the computer connected to its filter line.

 

[warning: the following is controversial, and I am not trying to convince anyone here, your mileage may vary, I can speak only for my system and our 4 ears]

 

I didn't expect any difference, but we found there were more punch to the percussions, and a clearer sound from mid-high (there's a type of tambourine-like sound which appears twice at the beginning) in the version up-converted with the filter on as compared to the one with the filter not connected.

 

It isn't a huge difference, but it was sufficiently important to make the 'filter on' up-converted version more compelling: you feel the rhythm better, the kick drum and other drums startle you more compared with the previously up-converted version which sounds a little flatter. Once you describe the changes verbally, one version cannot be mistaken for the other. We both heard the differences.

 

Now, bear in mind both these DSD128 files were up-converted from the same rip.

 

I shudder at the thought of doing a rip again with the filter on, then up-converting with the filter on, and finding out I can't live without doing that because I hear important differences...

 

Ultimately, I will certainly want to do that test.

[YashN]

I thought I had managed to wire up all three lines properly for tonight's testing, but we found out only 2 lines functioned after nearly a full hour of build. So, in the end, we didn't have much time to test tonight as it's already too late, but we did a few track extract with the iMac on one line and the amp on a second one.

 

The 3rd was supposed to be the external HDD, but that showed no sign of life there (the HDD is fine).

 

This means I will have to re-build the inlet distribution section as it's too flaky. I re-used the rails from a nondescript power distributor. It will be much better to use proper screw-on rails.

 

Results from the short testing tonight with the help of Diana Krall, David Bowie, Peter Gabriel, Tina Turner, Vangelis, Billy Idol and more:

 

I got the impression of a darker background: the music springs forth un-announced with great power. We recovered the feeling of 'they're here', punchy sound for percussions, but especially a very large height of the soundstage.

 

The notion of 'presence' was very well exemplified by David Bowie's 'Bring Me The Disco King', Thom Yorke's 'Street Spirit (Fade Out)', and eerily so with Cassandra Wilson's 'Harvest Moon', a cover of Young's song.

 

Incredible! This sound is going to be very, very addictive.

 

I'd really like to enhance inter-component isolation now, and then perhaps even plug in all the troublesome appliances like the cable modem and Wi-Fi router.

 

There is some serious quality lurking in clean AC power if you can do it right, and I've only done embryonic steps, really.

[Duke40]

Using the Isolation transformer in front of the Balanced power transformer does two things.

 

1. To slow the current peaks from the balanced transformer primary, so it acts like a choke.

2. Provide some soft starting for the balanced transformer.

 

There is no overlap, the isolation transformer and balanced transformer do different jobs.

 

If you had to choose and just use the one device, the balanced transformer would be it. Depending on how much rubbish there is on the secondary of the balanced transformer, this out of balance rubbish has to go somewhere, and ends up in the primary windings as an acoustic noise.

 

Use of an isolation transformer connected upstream of an Equitech transformer is a recommended practice from Equitech.

 

I found the use of a standard line conditioner in front of the Equitech restricted the dynamics and made the bass almost non existent. Would not recommend to use this device. Downstream is also a problem, since it regards the Equitech balanced supply as a fault although the filtering does work better on a balanced supply (if it uses a typical T filter).

 

To avoid cross contamination between components is not that simple, since an audio component will provide a different spectrum. The injection mains side spectrum from an amplifier is different to a CD player or computer, so the filter should be tuned individually. You can add standard EMC filters PLUS use the balanced supply, since the filters work better on a symmetrical supply, rather than one side grounded if you still wanted to keep the filters.

The balanced transformer does a great job of providing an effective cross pollution from other components on its own. Having several filters in parallel could cause a surprise in that there could be a resonance condition, but not likely.

 

@ One and a Half ... Thank you for your post.

 

I have seen you previously recommend;

 

Isolation Transformer upstream of Balanced Power transformer.

 

Previously I was doing it the other way around (due to wattage capacity of my power supplies), though I have long been curious about doing it the way you suggest (seen you mention it in other posts). Well, I ordered a larger Isolation Transformer so I could do as you suggest. Tonight it arrived and it is now upstream of one of my Balanced Power transformers.

 

It is so much better this way. Too busy enjoying to music to write coherent thoughts, though it is a noticeable difference. So thank you ! I appreciate your post above, it helps me understand the why , other people posting on this thread are more knowledgeable than me, so it is great when people like you and others take the time to explain the "why". Anyway, better get back to listening to Melody Gardot's Curreny of Man.

[One and a half]

There is neither an inductor nor a switch on the ground line in my current build. I don't plan to integrate the latter either - I think Lukasz thought it a good way at the time to easily prevent ground loops if hums occur, but if I had to put a switch it would never be on that line...

 

As for the caps from L, N to G (or H, N to SG/PE so long as we understand each other), I think the dumping of noise is precisely the goal, but solely for high frequency noise.

 

So I believe the diversion to ground is deliberate, but that's also why I was asking earlier about how to properly implement the inter-component contamination isolation as currently, there doesn't seem to be anything to prevent the noise along the GND line from one component from going to the next one.

 

How would you do it?

 

Managed to do some additional building and testing tonight - see below - including a very controversial finding (for many).

 

 

 

Thanks for the reference info, speedskater. I have Ott, Brown/Muncy lined up for further reading/research and already watched two of Armstrong's videos on Youtube, the earlier ones have bad sound, but the content is useful.

 

Agreed, the use of any impedance or device in a protective earth is prohibited, you just can't do this. Just looking at the circuit, the two caps, if you tie them to the neutral, can cause GFCI devices to trip at switch on. That filter BTW will work well on a balanced circuit than from a TN system.

[One and a half]

@ One and a Half ... Thank you for your post.

 

I have seen you previously recommend;

 

Isolation Transformer upstream of Balanced Power transformer.

 

Previously I was doing it the other way around (due to wattage capacity of my power supplies), though I have long been curious about doing it the way you suggest (seen you mention it in other posts). Well, I ordered a larger Isolation Transformer so I could do as you suggest. Tonight it arrived and it is now upstream of one of my Balanced Power transformers.

 

It is so much better this way. Too busy enjoying to music to write coherent thoughts, though it is a noticeable difference. So thank you ! I appreciate your post above, it helps me understand the why , other people posting on this thread are more knowledgeable than me, so it is great when people like you and others take the time to explain the "why". Anyway, better get back to listening to Melody Gardot's Curreny of Man.

 

You're very welcome, although I wish I could enjoy Melody's new music a little more, just have this barrier with that music and Melody's voice in the same continuum.

 

I tried to feed the Balanced transformer with a 2kVA online UPS, Eaton 9135. I don't know why, but the bass wasn't as pronounced or controlled with the UPS and am mystified why a lot of AC line conditioning equipment and a REGEN can affect these low frequencies. Maybe it's the most dominant energy and noise riding on it?

 

Anyway am back on the Isolation transformer feeding the balanced transformer, and all is good.

[Speedskater]

.....................................

So I believe the diversion to ground is deliberate, but that's also why I was asking earlier about how to properly implement the inter-component contamination isolation as currently, there doesn't seem to be anything to prevent the noise along the GND line from one component from going to the next one.

 

How would you do it?

I would try to reduce the resistance/impedance from one chassis to the next. Because the higher this impedance is, the more the noise currents will try to use your interconnects as a path back to their voltage sources. Bill Whitlock gets into this problem in some of his papers.

So from component to component, heavy short SG/PE conductors are best.

[Daudio]

... the Balanced transformer with a 2kVA online UPS, Eaton 9135. I don't know why, but the bass wasn't as pronounced or controlled with the UPS and am mystified why a lot of AC line conditioning equipment and a REGEN can affect these low frequencies... the Isolation transformer feeding the balanced transformer..

 

1-1/2,

 

How is a isolation transformer (and a balanced xformer) different then a Line Stabilizer/Conditioner ? I have a old Tripp Lite LS-604 that used to protect previous computer systems.

 

I don't know if I missed these explanations, but...

 

TIA,

[YashN]

I would try to reduce the resistance/impedance from one chassis to the next. Because the higher this impedance is, the more the noise currents will try to use your interconnects as a path back to their voltage sources. Bill Whitlock gets into this problem in some of his papers.

So from component to component, heavy short SG/PE conductors are best.

 

Very interesting, Speedskater, as I had planned to also implement a chassis-grounding system in my box.

 

Let me see if I understand this correctly: you're saying that to help with inter-component isolation within the mains, I should do chassis-grounding because in reality, the chassis are not at equi-potential and thus the stray currents will affect signal integrity by using the IC shield as return paths.

 

I think I agree with that latter premise.

 

However, what about the noise re-injected to the mains by each component's power supply?

 

If we do the chassis grounding well, are we providing an alternate, easier way for the power supply noise to be routed and hence aiding the AC line?

[YashN]

How is a isolation transformer (and a balanced xformer) different then a Line Stabilizer/Conditioner ? I have a old Tripp Lite LS-604 that used to protect previous computer systems.

 

I don't know if I missed these explanations, but...

 

They all do different things and based on the experience of audiophiles with much better gear than me, can be used together with benefits (system synergy is of course very important):

 

1. Here is some general info on an isolation transformer. The first time I heard about them was from my friend Alexander who was going to use one inside his DIY tube amp in lieu of a capacitor (the latter which allegedly adds coloration to the sound). Therefore, they're quite versatile and can be used not just in tubes but for AC power clean-up as well.

 

2. The FAQ from Equi=Tech has a lot of info on Balanced Power.

 

3. The Wikipedia page on power conditioners may make for interesting reading.

 

Ultimately, I think 1 and 2 provide more fundamental changes, so that if these are implemented first and properly, the need for 3 may be less (doesn't mean eliminated completely as conditioners can sometimes have a lot of combined features)

[YashN]

A couple of interesting reads last night in the light of speedkater's observations and my questions:

 

1. MIT Cables: Power-line noise - How Series Filters Work (and sometimes don't)

 

A very good overview of series filtering architecture, but also its shortcomings, and MIT's alternative, which is parallel filtering, thus not impacting current spike needs of amps.

 

It might be interesting for me to try a parallel filter line implementation dedicated to the amp and see what happens.

 

2. Thorsten Loesch (AMR/iFi) over at TNT-Audio appears to have posted a parallel filter as well.

[Speedskater]

'YashN' what I was attempting to describe is a small effort to what may be called.

 

Ralph Morrison:

STGP :: Signal Transport Ground Plane

ZSRG :: Zero Signal Reference Grid

 

Henry W. Ott:

ZSRP :: Zero Signal Reference Plane

 

Keith Armstrong:

Conductive Structure

[Daudio]

[ATTACH=CONFIG]19470[/ATTACH]

 

Yash,

 

Thanks for the xformer links - I'll get to them when I have more time later.

 

 

On the circuit diagram you posted, they have a some caps specified as "100n". From my days in DIY electronics there were 'uF', and 'pF' (micro farad and picofarad) caps, but I don't know what a 'n' cap is about ? Can you educate me ?

[YashN]

On the circuit diagram you posted, they have a some caps specified as "100n". From my days in DIY electronics there were 'uF', and 'pF' (micro farad and picofarad) caps, but I don't know what a 'n' cap is about ? Can you educate me ?

 

It's obviously n for nano, and since it's a cap it's nanoFarad.

[YashN]

'YashN' what I was attempting to describe is a small effort to what may be called.

 

Ralph Morrison:

STGP :: Signal Transport Ground Plane

ZSRG :: Zero Signal Reference Grid

 

Henry W. Ott:

ZSRP :: Zero Signal Reference Plane

 

Keith Armstrong:

Conductive Structure

 

Thanks Speedskater, these acronyms and references will come in handy for reading and research.

 

The more I think about this, the more I think many manufacturers have somehow forgotten about the utility of the ground plane, and what we now do is try and find solutions to that overlooked implementation post system setup...

 

What do you think of the Tripoint Troy devices?

 

 

 

• Dedicated EMI/RFI passive filtration component with proprietary modules made with classified composite materials
   
  
• Proprietary Pure Silver Grounding Cables
   
   
  
• No transformers, circuit boards, caps, op-amps, ferrites, coils, chips, plastics, LED’s or degrading parts that would create any electronic signature to the sound
   
  
• Eliminates ground loop
   
  
• Provides impedance ground match for all your components
   
   
  
• Vibration control tuning. Through resonance control and implementation of the right materials we can tune your Tripoint system to match your personal preferences
   
  
• Copper binding post provided to ground your components
   
  

[YashN]

Thanks Speedskater, these acronyms and references will come in handy for reading and research.

 

What do you think of the Tripoint Troy devices?

 

Additionally, what do you think of the idea of having a rack with metal, larger than the footprint of the largest component, and chassis ground all to it, and also make it a Faraday cage?

[One and a half]

 

What do you think of the Tripoint Troy devices?

 

[ATTACH=CONFIG]19476[/ATTACH]

 

Beautiful finish on the timber aren't they. Other than that the tripoint offers similar to the Entrec offerings.

 

Ermm, don't see how a parallel grounding system works when there's a mains earth wire doing the same job. Unless some components don't have an earth connected and the bonding cables are lower impedance than the interconnects to avoid ground loop....the frames are then bonded to earth, by design they aren't.

I would really need to listen and the effectiveness totally depends on the rest of the system and AC treatment.

Not totally convinced.

 

The line conditioners have filtering which is fine but the techniques are short on details and more on spin. For a true evaluation, an objective test with measurement would substantiate their product.

[YashN]

Beautiful finish on the timber aren't they. Other than that the tripoint offers similar to the Entrec offerings.

 

Very beautiful indeed, but I removed the 'African Bubinga' bullet point, as for my own purposes it is not too relevant

 

Now the thing is between the original Tripoint Troy vs the Entreq Trellus is that the Tripoint was geared towards chassis grounding only, whereas the Entreq was geared towards cleaning up Signal only.

 

Ermm, don't see how a parallel grounding system works when there's a mains earth wire doing the same job. Unless some components don't have an earth connected and the bonding cables are lower impedance than the interconnects to avoid ground loop....the frames are then bonded to earth, by design they aren't.

 

That's what I've been trying to find out too, if you check the last few paragraphs of the original post.

 

The thing is, the theory tells up the closing of the loop looks for the least impeded pathway. But is our common implementation close to the idealised theoretical aspect?

 

Secondly, note that the Tripoint does connect a ground pin to an outlet ground (it does have the two other pins to but these aren't connected inside the device, they are just there for mechanical stability at the outlet).

 

The Entreq, on the other hand, has no such connection back to an outlet... it's autonomous in that way. Still trying to figure out how this works.

 

I would really need to listen and the effectiveness totally depends on the rest of the system and AC treatment.

Not totally convinced.

 

Yes, I believe a systemic view is important, and hence the original title: at first I was concerned only with my AC filter, but the more I read and researched, the more I think all this is inter-related.

 

Some people have even reported great results using both products, i.e. the Tripoint Troy for chassis grounding, together with the Entreq for signal clean-up (grounding might be a misnomer here).

 

Here's an Entreq Silver Tellus:

 

[Daudio]

It's obviously n for nano, and since it's a cap it's nanoFarad.

 

 

Thats what I thought, as I said, I'd never seen that symbol before. (would have been clearer if "nf")

 

 

From Wikipedia: "while the nanofarad is uncommon in North America."

[YashN]

The correct way is indeed nF, but this was probably a small mistake by omission.