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

[Jud]

I had set aside some reading on Power Factor Correction to add to my AC filter box among other features (more on that later), and what do I come across? This:

 

Yep, exactly - when I researched inverters for solar and battery applications and started reading all about this stuff it reminded me very much of the literature for the MIT "Z" series power distribution and noise filtering components when they first came out. Richard Marsh, who designed that series for MIT, later designed the Monster Cable power distribution and noise filtering line (as well as designing some well thought of amps and preamps for his own company: Marsh Sound Design ~ Experience the Sound with Marsh Sound Design Products !!!).

[monteverdi]

Did you allow for the long 'break-in' periods? Some of these require time like 200 hours/weeks.

 

 

 

One of the advantages of the hospital grade ones is that the grip is a three-point contact. Caelin Gabriel explains this well in his little video on outlets. That's why the Hubbell H Grade is interesting to me.

 

Found out last night after reading about an AC distributor product for PA/music that the isolated ground has implications for RFI, so that's an interesting feature. The Hubbell I found yesterday was H grade and isolated-ground, and was about $13 on Amazon (no cryo), but last night it had already gone.

 

 

 

Take Five look cool, have you used their service already?

I used the PSaudio for months untill I really could not stand it anymore!

The three-point contact is actually what I am taking about and this configuration is shown in that video. Using a 15A plug the neutral plug blade has on contact with one blade and the edges of the other two. 2 wiper blades (as the hot side in all versions has) gives a much wider contact area than the three-point T shaped conformation. Hubbell shows the right conformation (albeit in a Ni plated version which I would avoid) on page 2 http://www.hubbell-wiring.com/press/catalog/a.pdf. The problem is that Hubbell makes 15A outlets with T and parallel versions and it is not very obvious which is which.

I used Take Five Audio before but I discovered the outlets after I bought them already.

[YashN]

Yep, exactly - when I researched inverters for solar and battery applications and started reading all about this stuff it reminded me very much of the literature for the MIT "Z" series power distribution and noise filtering components when they first came out.

 

Now, to come back to my previous comment on regulations and all: they might be congruent as you said in the sense that both domain, gov and audio, want the reduction in AC back-injected noise. However, with regulations and standards, it is often the case that the regulation thresholds aren't good enough for audiophile uses.

 

I haven't read the actual regulations yet, but the existence of a lot of products to deal with AC filtering and power conditioning for audio purposes does hint at the evidence.

[YashN]

You found a lot of the Core Audio nonsense!

 

Hoping you can write more about your thoughts when you get some time rather than making one-liner criticism which doesn't help anyone.

 

Cheers.

[YashN]

Inspired by this thread, I just floated the ground on my Tripplite IS1000HG, WOW! I should have done this a year ago.

 

Was it the ground float of the secondary neutral as mentioned on avsforum?

 

Just saw that from the Regen thread.

 

Interesting, it would be cool to know why the original poster says that for audio and video this must be done. Hopefully, there is no safety implications (as you would get with ground floats and cheater plugs).

[sandyk]

Hopefully, there is no safety implications (as you would get with ground floats and cheater plugs).

 

I suspect that there may be. Where would you be for example, if the secondary of the transformer broke down to it's core ?

Perhaps a question for 1 1/2 ?

Even when I don't connect any of a circuit to mains earth, I normally mount the transformer (depending on type ) on a metal plate or a piece of copper clad PCB, where only the plate/copper side of the PCB is connected to I.E.C. mains earth.

The plate is also spaced a little above the bottom of the case to permit improved ventilation without any protruding bolt heads.

[YashN]

Did you allow for the long 'break-in' periods? Some of these require time like 200 hours/weeks.

 

This reminds me that I need to do that with my own filter lines even though they're the totally normal, cheap outlets you can get at the hardware store. Mechanical/Heat break-in can last rather long and probably explains why the sound was changing daily (improving i would say). I'm only using 3 of the outlets for now, so I will need to mark them later so that I know the others need some break-in as well.

 

All right, I fairly went all-in this afternoon: removed the amp and connected the external DVD drive to that filter line, and ripped a few CDs I got today (including Hans Zimmer's 'The Last Samurai' - this sounds huge!).

 

Since Lionel was still taunting me from his CD cover, I had to do it...

 

It sounds like the up-conversion to DSD128 of the XLD Secure (slower than Burst) rip made with the filter sounds the best... Going to wait for my gf to come back tomorrow night and get her feedback.

 

Haven't checked the actual rips, but I could do that too.

 

Went so far as to disconnect the modem and router as soon as Audiogate had Tweeted, all that in the dark (no lights on).

[YashN]

I suspect that there may be. Where would you be for example, if the secondary of the transformer broke down to it's core ?

 

Me? Nowhere: not only would I not be there, but I wouldn't ever think of removing grounds on equipment, and even more so if there's not a complete explanation of the reasons why it 'should be done' and a complete description of the risks!

 

I would rather fix the overall system power, grounding, isolation than remove a ground.

[sandyk]

Yashn

If you are able to hear differences, with and without the filter, are you able to verify that the checksums of both versions, even the upsampled versions , are still the same ? Incidentally, for a couple of years now, my rips have been done with the PC unplugged from the Broadband Modem.

 

Regards

Alex

[YashN]

If you are able to hear differences, with and without the filter, are you able to verify that the checksums of both versions, even the upsampled versions , are still the same ? Incidentally, for a couple of years now, my rips have been done with the PC unplugged from the Broadband Modem.

 

I only checked the file sizes (full file sizes) and they are the same, so I expect the checksum to be the same as well.

 

Waiting on my gf's arrival tomorrow to get a second pair of ears (very good ears at that).

 

It's when I pay attention to attack punch (drums & percussions) and the space around the instrument (probably because of room reverb or artificial reverb) that I can hear a difference.

 

I won't tell her what I hear so as to get her pure feedback.

[YashN]

I even turned off the fridge for a while during ripping, but then the thought of spoiled food brought me back...

[jabbr]

Some of the Topaz ultra-isolators can be wired as balanced. Stick a GFCI power strip or box as output of that? Those are some well made, low capacitance, transformers. Missing something?

[YashN]

Some of the Topaz ultra-isolators can be wired as balanced. Stick a GFCI power strip or box as output of that? Those are some well made, low capacitance, transformers. Missing something?

 

Just have their brochure open: these look good. How would you use them?

[jabbr]

Just have their brochure open: these look good. How would you use them?

 

I was thinking: 2 in series, the first unbalanced (isolator) and the second balanced. ?

[YashN]

I was thinking: 2 in series, the first unbalanced (isolator) and the second balanced. ?

 

They look like versatile building blocks.

[One and a half]

I suspect that there may be. Where would you be for example, if the secondary of the transformer broke down to it's core ?

Perhaps a question for 1 1/2 ?

Even when I don't connect any of a circuit to mains earth, I normally mount the transformer (depending on type ) on a metal plate or a piece of copper clad PCB, where only the plate/copper side of the PCB is connected to I.E.C. mains earth.

The plate is also spaced a little above the bottom of the case to permit improved ventilation without any protruding bolt heads.

 

If the transformer broke down to the frame, or an live AC wire fell off a terminal and ended up on the metal chassis of an amp say are two scenarios where your interconnects are at mains voltage. Since there's no return to earth no fuse or circuit breaker will blow, the shield on the interconnects will be live, not 1/2 but at full mains voltage.

On the contrary, I find that earthing every component, amps, CD, radio and DACs, the lot benefit from being earthed, since the chance of potential differences due to interconnect shield voltages are very, very low and avoids ground loops from day one.

 

I find it irresponsible, perhaps too strong a word, but certainly misguided for Superdad to peel back earth wires and tape them up on equipment that's meant to be earthed. There are ways around ground loops, often difficult to solve sometimes, but bypassing safety systems is not one of them.

[lmitche]

If the transformer broke down to the frame, or an live AC wire fell off a terminal and ended up on the metal chassis of an amp say are two scenarios where your interconnects are at mains voltage. Since there's no return to earth no fuse or circuit breaker will blow, the shield on the interconnects will be live, not 1/2 but at full mains voltage.

On the contrary, I find that earthing every component, amps, CD, radio and DACs, the lot benefit from being earthed, since the chance of potential differences due to interconnect shield voltages are very, very low and avoids ground loops from day one.

 

I find it irresponsible, perhaps too strong a word, but certainly misguided for Superdad to peel back earth wires and tape them up on equipment that's meant to be earthed. There are ways around ground loops, often difficult to solve sometimes, but bypassing safety systems is not one of them.

 

Thanks for the clear explanation. To summarize, floating the secondary neutral on the isolation transformer disables the ability of a circuit breaker to detect a short, or over current condition as the common reference is gone.

 

And by implication, any device plugged into the "modified" isolation transformer has it's safety mechanism disabled as well as the reference potential has been changed.

 

Did I get that right?

[Superdad]

I find it irresponsible, perhaps too strong a word, but certainly misguided for Superdad to peel back earth wires and tape them up on equipment that's meant to be earthed. There are ways around ground loops, often difficult to solve sometimes, but bypassing safety systems is not one of them.

 

Just to be clear, I do not advocate that anyone else do this. It is a personal choice and risk that I take strictly for my own system.

 

As can be seen in the below photo, our JS-2 LPS properly grounds both the chassis and the transformer's ground wire to the earth pin of the IEC connector. The design of the unit and all components within meet or exceed EU, UL, and AU safety standards (though due to excessive costs for certification and bureaucratic BS, and the fact our supplies ship directly to end-users, I am not stickering the units with a CE mark). The build quality and safety of the JS-2 is top tier, so there is no worry--except for those who like to worry.

 

 

P.S. One ground that we DO "float" with the JS-2 is its DC output ground. That is, unlike most any other LPS, the output ground is not common to the chassis and AC mains ground. We think this is a great advantage and helps keep house mains grunge out of the components the supply is powering. (And this is not an easy feat to pull off as it requires thermal pads for the regulators that are both electrically insulating while still having a excellent thermal performance; Of the thousands of types out there, we found only one that actually meets these criteria in out application--and I have to hand-cut and punch them as the material is not available die cut, though I may soon pony up the $ to have them done.)

[YashN]

If the transformer broke down to the frame, or an live AC wire fell off a terminal and ended up on the metal chassis of an amp say are two scenarios where your interconnects are at mains voltage. Since there's no return to earth no fuse or circuit breaker will blow, the shield on the interconnects will be live, not 1/2 but at full mains voltage.

 

Ugh! See why it's always a bad idea to circumvent safety earthing?

 

On the contrary, I find that earthing every component, amps, CD, radio and DACs, the lot benefit from being earthed, since the chance of potential differences due to interconnect shield voltages are very, very low and avoids ground loops from day one.

 

I like that approach too. It may be more work in the common cases, but it is safer and better engineered.

 

I find it irresponsible, perhaps too strong a word, but certainly misguided for Superdad to peel back earth wires and tape them up on equipment that's meant to be earthed. There are ways around ground loops, often difficult to solve sometimes, but bypassing safety systems is not one of them.

 

Yeah, I don't like that way of proceeding either.

[YashN]

As can be seen in the below photo, our JS-2 LPS properly grounds both the chassis and the transformer's ground wire to the earth pin of the IEC connector. The design of the unit and all components within meet or exceed EU, UL, and AU safety standards (though due to excessive costs for certification and bureaucratic BS, and the fact our supplies ship directly to end-users, I am not stickering the units with a CE mark). The build quality and safety of the JS-2 is top tier, so there is no worry--except for those who like to worry.

 

[ATTACH=CONFIG]19619[/ATTACH]

 

Solid piece of John Swenson Engineering indeed. If I could wire up everything with that kind of power and the Regen, I think it would be awesome.

[YashN]

I was thinking: 2 in series, the first unbalanced (isolator) and the second balanced. ?

 

Very interesting, jabbr.

 

I had this at the back of my mind because for the time being, I am mostly experimenting with and designing the AC filter, vibration isolation and damping and power & interconnects:

 

1. Use a couple of similar step-down transformers, wire them secondary to secondary, filter with suitable capacitors in between for an isolation transformer prototype.

 

2. Derive a balanced power transformer from the iso transformer prototype.

 

I think the iso transformer can replace on integrate one filter line in my box, and possibly the balanced power one will come before the whole filter box (i.e. between mains AC and my filter box).

 

How does that sound?

[YashN]

The owner dropped around today and I was going to ask him about how things are wired up internally here since he's an electrician.

 

Didn't manage to get hold of him before he left, so my thoughts of installing dedicated lines are on hold for now. There are some breaker spaces left in the box though.

[JohnSwenson]

According to the NEC it is legal to use a GFCI without an actual EARTH connection, as long as you have a sticker on it saying the ground pin is not connected to earth.

 

If any current is flowing between either hot or neutral and the ground pin the GFCI opens both hot and neutral thus eliminating the threat.

 

So an isolation transformer with a GFCI on the secondary should be both legal and still maintain decent safety. Now some people say that GFCIs are horrible for sound, but THAT is a different issue.

 

John S.

[sandyk]

Hi John

But how many people who self installed their own Isolation Transformers would be presently using a Ground Fault Circuit Interrupter at the secondary of their isolation transformers ?

I suspect not too many.

 

Alex

[lmitche]

John, could one use the GCFI outlet in parallel with a regular outlet so when the GCFI trips it brings done the second outlet ? This would avoid the noise issue from the GCFI outlet as the equipment could be fed from the second non GCFI outlet.