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

[YashN]

This paper has become rather old.

 

But 5 years later it hasn't happened yet.

 

To the rescue comes Middle Atlantic (owner of Exact Power) they have a longer (65 pages v. 35 pages) paper. Many of the added pages are directed at pro audio or large A/V systems.

 

Hey, there you are!

 

Thanks a lot for sharing.

[YashN]

"Power Distribution and Grounding of Audio, Video and Telecommunications Equipment White Paper"

 

Cool diagram of Mesh Grounding for equipment racks on p.59 there.

 

Combining this with equipment vibration isolation for my setup will probably need a good re-think but it should be well worth it.

 

Another good reference mentioned on that page: 'Handbook of EMC' by Warren Lewis.

[YashN]

[ATTACH=CONFIG]19995[/ATTACH]

 

 

And best of all, I'm enjoying an estimated 60 dB of common-mode noise reduction, some additional normal-mode noise reduction, and the prevention of "backwash" noise from the DAC coming back onto the power circuits.

 

It's a very affordable power conditioning solution.

 

Very cool, Mike. Do you get the experience of hearing 'new things' in well-known tracks? It would be interesting to compile them, I'll be writing down my own too.

 

Do you think it would be good to replace your big iso by a Balanced Power one? (assuming it isn't already a BP one)

 

This is a great setup for further experimentation, I would experiment with chassis grounding, signal cleanup (or what some call 'signal grounding' like Entreq does, and perhaps also try a directional cable between DAC and amp if it's unbalanced (e.g. shielded, but shield only connected at DAC end), Linear PSUs.

[YashN]

Note that Warren Lewis coauthored the Ralph Morrison book.

 

"Grounding and Shielding in Facilities"

 

Chapter 7 'Facility Considerations' covers the correct ways to do what the grounding boxes poorly attempt to do.

 

I purchased the book, used on-line for 10 or 15 dollars. You may be able to get a pdf for much less.

 

Definitely on my wish list. EMC is very interesting indeed.

[YashN]

Wanting to understand "why" - I don't understand the need to do this. In general, I can easily imagine that a short, heavy gauge connection between the two chassis would encourage ground currents to flow there rather than on the longer, narrow gauge shields of the signal interconnects, but as I described in my previous post, the RCA interconnects form a horseshoe with the DAC and amp.

 

I cannot envision any path through which a ground current could loop. That's why I think I can abandon any concern for the huge difference in supply voltage coming into the two chassis (117.5 vs. 109.9).

 

There could be some good info from post #55 onwards, and check the end of the original post as well.

 

It's interesting to see for instance, the traditional way of looking at ground loops and interference, like say Speedskater, and for example, someone focusing a lot on EMI/RFI like I do (there's a recent thread - look for 'Beyond Bit-Perfect: EMC'.

 

To take a point of comparison, Speedskater mentioned low frequencies for audio. However, for the signal cleaning of the Entreq products, I rather consider very high frequency pollution at the signal ground and try to get these to an autonomous box with the lowest impedance path possible.

 

The exchanges we had around chassis-grounding which he recommended initially are really cool too.

 

In another forum, a few people with good equipment benefited from chassis-grounding, and then when they tried the 'signal grounding' (this could be a technical misnomer so I hesitate to use it, I rather write about 'signal cleanup'), they further benefited.

 

There are a few additional venues of study I have done which could show there is even more happening, but for now, I think it's already a rather big chunk of info to digest in the form of EMC. The 'Beyond Bit-Pefect: EMC' thread is open to explore this further in a world where ambient frequencies are changing rapidly to be higher and higher, and additional to explore the 'gray areas' of analogue and the electrical issues within our 'digital systems'.

 

The additional venues could make a whole new forum, and partially fly in the face of a lot of conventional theory and applications, so I am not sure this is the proper forum for it, seeing even the conventional and known stuff sometimes gets derided or misunderstood. Let's just say for now relative to this is that we waste a lot of electricity.

 

This said, I think I have a good handle on at least the grounding as used by the Tripoint and Entreq devices as built and tested prototypes for each and each gave me great results although I know for a fact the implementations are not very good, so this is promising.

 

A good point of questioning came about when Speedskater said he'd recommend cleaning up the signal by doing the chassis-grounding, but some people have done that and further benefited from the 'signal clean-up'.

 

Some say Balanced Power resolves a lot of these issues, but you can still try the other implementations and give these a good listen. It's all system-dependent too as some equipment may well not benefit from chassis-grounding or signal cleanup. The Shunyata description of their Chassis Grounding System is very good at saying that.

 

The ideas of this thread need to be tested by everyone if they want to.

[YashN]

I haven't seen a Balanced Power solution I can afford, but I've also not found any well-written articles contrasting the benefits of Balanced Power against the use of tiered Isolation Transformers.

 

Check these out:

 

1. Jon Risch - DIY AC Balanced Power

 

2. Felicia - DIY AC Balanced Power ("an extension of Risch's iso transformer")

 

3. Building " The Cheapskate!" ($125 or less) Balanced Power Unit

 

I would say BP is more fundamental than iso transformers, but you can still earn cumulative benefits.

 

Bill Whitlock (Jensen Transformers) provides a very negative opinion of Balanced Power on Page 201 of this PDF:

 

That's OK: it shows us BP isn't a panacea, so that we know we can still reap benefits with additional implementations depending on our system.

 

So a few interesting implementations would be BP or BP + iso or dedicated line + BP, etc...

 

Given how I'm doing my "power conditioning" all wrong, I'd really love to hear my system done right! :-)

 

Not wrong at all, I think you're already far ahead of most of us here.

[YashN]

I haven't seen a Balanced Power solution I can afford

 

I thought I saw jabbr post an image and a link for a small and versatile transformer that can be configured in iso or BP mode. Checked rapidly back in the thread but didn't find it.

 

The amount of info in this thread is staggering!

[YashN]

A very good set of videos on Linear Power Supplies I was watching the other night. I think I could build one from the parts in my salvage boxes.

 

 

Simple Linear Power Supply build by Phil Levchenko:

 

 

 

[YashN]

Well no!

There is nothing in the writing of Armstrong, Morrison or Ott limited to low frequencies! Most of their work is directed towards communication, data processing and industrial systems. So much of the focus is on the difficulties of higher frequencies. Add in Jim Brown who is an audio guy, but he is also a Ham radio operator. Many of his papers are directed at radio frequency interference.

 

Except you were the one focusing on 'at these low frequencies'. I totally agree that there's a lot of high frequency content that is spurious and can induce losses for SQ (the high freqs can be in power or near the signal.

 

I have taken the approach of combatting these when I can.

 

While documentation is rare for Entreq like products, they appear to be the exact opposite of good high frequency solutions! In some of the user descriptions, they might make great interference antennas.

 

It could be... Or it could be diverting these high frequency contents away from the signal path and inducing losses at the box...

 

The only difference between traditional troubleshooting methods and modern ones is:

Now good inexpensive battery powered test equipment is available. In the past, hooking up AC powered test equipment could change the system situation that you didn't know what you were measuring.

 

I wouldn't say this is the only difference: to me there is a vast difference in the profile of ambient energy nowadays compared to the not-so-distant past.

[YashN]

Hi, I recently stumbled into a cache of 5 overstock audiophile 1000VA balanced power transformer units, 4 110 volt US models, and 1 230 volt European model. These units are UL and CE compliant.

 

Hohoah! Treasure!

 

I get cold feet with my transformers: I suppose I'll end up hacking them out and then guerilla measuring them anyway but in the meantime, I'd rather get their precise specs, but it's super hard to find their datasheets online.

[YashN]

Which transformers do you have?

 

These:

 

Found a few transformers I could play with:

 

1. One from the powered subwoofer from a malfunctioning LG Bluetooth system

 

2. One from the power supply from an old VCR

 

3. One from the power supply from an old DVD player

 

If I remember correctly the old DVD player was a Pioneer, the first one is from that LG Bluetooth soundbar, but I found the discarded subwoofer just outside my place and since it's not the whole system I can't test the pairing as it needs the remote, so I figured I could salvage parts from it.

 

The one from the VCR is the biggest for now (not counting my huge Elcors in the SET Tube Amp which won't budge from there) but a search online for part number was rather fruitless.

[YashN]

This thread seems to be splitting into unlimited directions.

 

It wouldn't have if the pure initial AC Filter I was building didn't bring along with it so many additional questions. c.f. the whole of post #1...

 

But line-borne problems are dealt with differently than air-borne problems. Which do you want to discuss?

 

Anything related to the title of the thread. System-wide view/model is important, which is why we have the 3 requirements of EMC and not looking at a single component in isolation.

 

It's a good thing that electricity doesn't work this way or your computer wouldn't function.

 

It doesn't, eh? Well, which 'electricity' are we talking about here? I mentioned high frequency content.

 

How do you think that these magic boxes could divert part of the signal?

 

Already mentioned that a few times in that very same thread.

 

So very, very true! Now any product you purchase and connect to AC power has the potential to generate noise and interference.

 

Indeed, not every one of them have a properly designed power supply like the Uptone JS-2, but... additionally, what makes you think any new product purchased nowadays has to connect to AC power? Sometimes they don't and they still generate noise and interference.

 

I wonder when audiophiles will stop trying random solutions to cure known and imagined problems and get down to serious investigation.

 

Nothing in what I do is random although it may appear so to you

[YashN]

As an aside. If you just want +5V you can use fixed resistors with a 3 to 1 ratio. e.g. 100/300,110/330,120/360 etc.

This gets you very close to +5V normally.

 

Thanks Alex and thanks for the additional info on the JLH circuit in the other thread too.

 

I think it would be rather wonderful to tackle a little Linear PSU project, but I've been putting that and other items on the To Do List off a little.

 

The list is quite big now:

 

1. Enable all 6 filter lines

2. Re-wind the CMC's differently

3. Enable a customised parallel-filter line for the amp

4. Test with amp on filter line (initial or parallel) vs separate AC outlet

5. Test filter configurations for short DIY USB Cable

6. Build directional RCA cables

7. Other features for AC Filter Box

8. Improve chassis grounding

9. Improve signal clean-up

10. Test DIY iso transformer

11. Test Linear PSU

12. Identify problematic PSUs

 

If I had a proper oscilloscope, maybe 12 would have been easier. Some of the culprits I am looking at which are in the vicinity of the main computer are:

 

a. External USB HDDs (2)

b. USB Soundcard

c. Audio Mixer

d. Hacked Linksys Router

 

Probably, this week-end, I will get the opportunity of moving the Cable Modem away, and also removing some other PSUs hanging around in the general audio/video area, will be dependent on what we decide to do for her holidays.

 

I am also thinking of a better segregation of the A/V equipment, perhaps making sure the TV, Blu-Ray and Apple TV are as far as possible outlet-wise, but to some extent the stereo setup and the surround setup are shared.

 

Oops, and I forgot I also need to repair one input of my SET Tube amp and try to find a way to reduce the operating noise of the Win PC (it's noisier than the default Mac setup for sure).

[YashN]

Nothing in what I do is random although it may appear so to you

 

So tell me about your tests and measurements?

What test equipment did you use?

 

************************

That USB O-scope would be a good start.

 

I'm not so fortunate to own one: I built my own circuit about 1 or 2 years ago to troubleshoot my Polysix. For that I use the Mac input so it maxes out at 96kHz, which means I only get readings up to 48kHz, so it's a severe limitation in what I can manage currently and hence I can only progress at a snail's pace because the only real way I can perceive changes is by implementing and then sitting down with extended listening sessions, which I did for the AC Filter lines (I built them myself), the chassis grounding (I did that myself and made my own grounding cable which is a flat braid) as well as the signal clean-up (my posts about the results of our listening impressions are in previous posts in this very thread if you've missed them, I re-used a previous iteration of my RCA connectors and used that to connect the DAC and the amp through copper).

 

I saw Miska link to a couple of good USB scopes, but man, they are really expensive, one is even at $10K. I can't justify that purchase currently (one could have concluded that since my main DAC is a $190 one...). Maybe if I could borrow one from a friend around here, but the only obsessive I've seen around here is my own reflection in the mirror.

 

I use a couple of Windows Scope software through WINE on the Mac. I've been able to see a few interesting things with that with my DIY short USB cable, including the 8kHz and harmonics noise.

 

Since you must be way ahead of me in terms of Scope and probably other equipment, where are your experimental results because I sure hope you are experimenting and listening or if you can, measuring rather than confining yourself in thoughts of what should work or what should not?

[YashN]

Thanks for the assessment. I feel as if I'm just received the Good Housewiring Seal of Approval. :-)

 

For a second from the activity list I thought I saw 'Good Housewifing Seal of Approval'

[YashN]

Some posts further back I was planning to make a database of tracks and sounds to listen for that are not as distinct before system enhancements and which become so afterwards. These little details can usually be muddied or don't stand out as much but then can be used to listen to how any system tweak or enhancement sound. It's interesting to do this with tracks you know well and which show you some 'surprise' sounds and performances after new tweaks.

 

Here's an example of that with Sade's Best Of Album:

 

 

1.

 

 

0:48 Low percussion

1:20 Couple of High Claves

1:38 Pad

 

 

2.

 

 

0:01 Low Perc line

0:18 Reverb Kick

1:13 Triple of Reverbed Mid Percs

1:29 Whistle-like melody

2:40 High Perc Line + Lower Perc lines

 

 

3.

 

 

0:08 Triplet of Mid Percs

0:12 Quintet Percs

0:20 High Percs

0:55 Hi-Hat fill + Crash

1:22 Cabasa

1:53 Rhythm guitar + mid perc + Pad

2:02 High Whistle

2:02 String Twang

2:10 Triangle lines

 

 

4.

 

 

0:15 Low Vol Mid 'Croak'

0:39 Duo of PIano-like bass

1:06 Hollow tube (also 1:11, 1:16)

1:22 Flute-like Ditty

1:40 Low Backing Vocal, growing

2:04 "a-ah" Vocal Effect

 

 

 

5.

 

 

Overall Live Feel

 

 

0:22 Perc + Rising and Falling Tone

0:23 Hi-Hat/Brush + Metal Bars

0:49 Triplet of Percs (third one is reverbed)

 

 

6.

 

 

0:18 Vocal-like Bass Sequence

 

 

7.

 

 

0:22 Solo Guitar

0:28 Flute

0:57 Mid and Low Perc Lines

1:23 Single Perc strike

2:10 Low Perc

2:32 Low Guitar

2:41 Sound Effects (droplets)

 

 

8.

 

 

0:40 Low Guitar Sequence

0:54 Duo of Percs

1:01 Mid Percs (repeat triplets after this)

 

 

9.

 

 

0:06 Triple low notes

0:09 High note

0:12 Sound effects (guitar, vocal-like)

0:28 "Ha"

0:44 Rapid cabasa-like notes

1:05 Tube or vocal-like couple of notes

1:14 Reverbed strike

1:32 Tambourine Line + Dist Guitar Sequence

1:49 Dist Guitar

1:56 Clean Elec Guitar

2:28 High Triangle-Like notes

[YashN]

That was a lot of work. I'll play them later on Tidal HiFi and follow your notes.

 

Lots of fun rather

 

There are two modes in which I listen: one is focused when I barely get any additional stimulation except from the tracks and the other one is filtered, where I am listening while doing something else like browsing and replying to forum posts.

 

The latter is good for startling events, the rest is usually filtered out a bit since attention is divided.

 

Hadn't thought of Tidal for comparisons but that's a good idea. Not too big a fan of streaming someone else's music on a rental basis though.

 

Let me know what you think.

[YashN]

Hi all, FYI - I just posted the details of a group buy for the balanced power supply in the Buy & Sell Audio and Computer Components forum.

 

That's very nice, Larry.

[YashN]

Which transformers do you have?

 

Here's an actual pic from the supposedly malfunctioning LG Bluetooth subwoofer from a soundbar system:

 

 

 

 

Not seeing the datasheet or the specs mean I don't have ratings figures as well as pin-out descriptions.

 

I suppose I could remove it and test it to some extent for the secondary terminals, but not sure I can derive the rating from it.

 

Below, you can see their AC filter line, after a while of pouring over schematics, you get to recognise these on various PCBs rather fast. It looks like MOV -> X-Cap CLCL -> Full-wave rectifier -> YCap.

 

The 'L' here is probably an AC-specific Common-Mode Choke.

[YashN]

But I've always wanted to try a balanced power unit and that one looks pretty sweet. I'll post any questions over in that thread.

 

And don't forget this thread for your listening impressions if you try BP, Superbad.

[YashN]

There were a few very interesting AC-related posts mostly by John Swenson and also Superbad Alex over on the "Beyond Bit-Perfect: EMC" thread:

 

Initially, John had posted this about his recent findings about noise on AC lines nowadays as compared to the same 5 years ago:

 

On AC power lines, things have gotten MUCH worse in recent years. 5 years ago I did a fairly detailed analysis of what was on my AC line in my house. A few weeks ago I re-did the analysis and was horrified at what I found. There is so much more stuff on our AC line today. I have a feeling that approaches like "line filters" etc are just going to be swamped by this much "noise". I'm really thinking that brute force approaches like motor generator sets are getting to be appropriate.

 

...

 

That should block pretty much anything. Or you can do it with air pressure in tanks.

 

Since I was contemplating power generation devices like batteries and solar more recently, I was gong to ask John if he could expound on what it is that he found. Little did I know that while I was researching the related subjects, Superbad Alex had posted the following additional info on John's investigations and Superbad's own fishing for a proper AC regenerator:

 

John does turn off a lot of stuff in his lab when looking at the AC line. One of the key things he mentioned to me in talking about the degradation of supplies house mains (and he has a nice grid-tied solar system BTW) is that the utility companies (and government in some cases) are using the grid for communication and monitoring of all sorts of things. Those smart meters use high frequency carriers to send usage data all day long. I seem to recall John saying he was seeing all sorts of stuff on his mains at 19KHz.

 

He really wants to do some serious measuring of power supplies and what they kick back into the wall but the mains itself is far noisier than any of the SMPS units (at the AC side) which he has attempted to compare! I bought him one of those CyberPower power factor corrected "sine-wave" UPS units, but it's not clean enough. Next step may be for use to invest in a real AC regenerator (basically a 60hz power amp).

 

So, while we're worrying about this...

 

 

...they seriously messed up your AC & sound quality (and probably health as well) with these:

 

 

[YashN]

here is rough schematics of system1

 

Both systems have custom balanced isolation trafo power systems with 3 stage serial/shunt/serial HF filters .

That advanced power cleaning system have practicaly no influence from SMPS, including noise from computers.

 

Thanks a lot Ivars.

 

For others in this thread, I asked Ivars if he could share some info about his setup as he mentioned it in another thread (Regen related). It's cool he can share the info as well as took the initiative to find the proper thread (which I hadn't even mentioned), so I appreciate it very much.

 

Ivars, I would be interested in more details about your 3 stage serial/shunt/serial filters if you can share the details as well. Thanks again.

[YashN]

Another great company is Equitech Balanced Power. They have the Q which is 20 amps and the Son of Q which is 15 amps. Excellent well built.

 

Yup, and if you read about how many companies build their solution, they seem to have mostly settled on building on a Plitron transformer, some recent and high-quality ones use a Plitron LoNo (Low-Noise) one.

[YashN]

I don't know why it was hard to find this specific kind of info before - remember when I struggling about winding directions and had to go back to first principles and rules of thumb from Physics class to derive the effect of chokes? - but here is a great little page from Murata:

 

 

[YashN]

I am wondering how to best organise the A/V equipment with respect to dedicated lines.

 

Video gear:

 

1. TV

2. Apple TV

3. Blu-Ray player

 

Audio gear:

 

1. SS amp

2. SET Tube amp

3. Turntable

 

What is shared between these two is the iMac, a centre channel, surround speakers and the subwoofer.

 

I am thinking of putting video and audio each on a dedicated line.

 

The question is: where do I put the shared equipment? Should be use a third dedicated line or this is too much?

 

Then comes the question about the recording gear (mostly synths, but one soundcard and an analogue mixer). Another dedicated line?