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Em2016

Discussion of AC mains isolation transformers (started w/posts moved from "LPS-1 troubleshooting" thread)

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Em2016   
A few quick words on what is happening with the transformers I have been talking about and how to setup a system using them.

 

It starts with the leakage loops I have been talking about recently. Remember these are loops that go through the AC mains, power supplies, DC output of power supplies, interconnects (audio and digital) to other power supplies and back through the AC mains. Note this has nothing to do with the "third pin" safety ground. I've gone over this in detail in other posts.

 

You can get rid of the noise generated by these loops in two ways, block the loop somewhere in the loop (The LPS-1 does this for certain paths), OR decrease the impedance along the loop, if the impedance is lower the NOISE generated by the CURRENT will be less.

 

This post is all about the AC side of this.

 

To decrease the impedance on the AC you need to have the lowest possible amount of wire, filters, anything else between the outlets you plug your AC cords into. This specifically means NO filters in the power strips, they dramatically increase the leakage currents between boxes plugged into such a strip.

 

Ideally you should have ONE power strip with EVERYTHING in your audio system plugged into that one strip. By everything I mean everything that has an AC plug that is connected into your audio system somehow. This includes power amps, computers etc.

 

Note this is the ideal situation, try and achieve this if you possibly can. For example if you are in a 120V area and you have two 700 watt power amps you can't do that, so some other arrangement will have to be made.

 

BTW the power strip for this does not have to be very expensive. I am currently using a $35 Tripp Lite power strip, no nothing inside, circuit breaker, switch, outlets and wires. Just this alone replacing my $1000 audiophile power filtering strip made a huge improvement in sound.

 

So now you have gotten rid of those expensive filtering power strips, doesn't that leave your system exposed to all the crud on the AC line from your other deices in your house and your neighbors as well? That is where the isolation transformer comes in.

 

These transformers with the very low interwinding capacitance are VERY effective noise filters AND surge suppressors without increasing leakage currents. MANY MANY of the filtering systems in your audiophile power strips DO filter out the noise, BUT they add large amounts of leakage currents into the system. These isolation transformers block the noise without adding leakage currents.

 

So the system as a whole is the isolation transformer feeding a very simple, very low impedance power strip with everything plugged into that power strip. This gets rid of external AC mains noise, deals with surges and provides a very low impedance AC mains path that significantly cuts down on the noise from the leakage loops.

 

Note it does not decrease the actual leakage loops, they are still there, it just decreases the NOISE generated by these loops, and THAT is what really matters.

 

So devices like the LPS-1 will BREAK loops from the digital side of things, which are usually the worst ones in a system, the above AC mains topology will decrease the noise generated by the leakage loops in the rest of the system, DACs, preamps, poweramps etc.

 

John S.

Thanks for sharing John. Always nice to see simple but effective noise reducing solutions that doesn't break the bank at all. I'm constantly learning from your posts. Having purchased a microRendu and now an LPS-1, your time spent sharing your experience and knowledge around here is not wasted, I promise you that! :-) I think many other customers of the products you've worked on would agree

 

 

Sent from my Blackberry DTEK50 using Tapatalk

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JHG   

So now you have gotten rid of those expensive filtering power strips, doesn't that leave your system exposed to all the crud on the AC line from your other deices in your house and your neighbors as well? That is where the isolation transformer comes in.

 

These transformers with the very low interwinding capacitance are VERY effective noise filters AND surge suppressors without increasing leakage currents. MANY MANY of the filtering systems in your audiophile power strips DO filter out the noise, BUT they add large amounts of leakage currents into the system. These isolation transformers block the noise without adding leakage currents.

 

So the system as a whole is the isolation transformer feeding a very simple, very low impedance power strip with everything plugged into that power strip. This gets rid of external AC mains noise, deals with surges and provides a very low impedance AC mains path that significantly cuts down on the noise from the leakage loops.

 

Note it does not decrease the actual leakage loops, they are still there, it just decreases the NOISE generated by these loops, and THAT is what really matters.

 

So devices like the LPS-1 will BREAK loops from the digital side of things, which are usually the worst ones in a system, the above AC mains topology will decrease the noise generated by the leakage loops in the rest of the system, DACs, preamps, poweramps etc.

 

John S.

 

John, regarding an isolation transformer, something like this? https://www.amazon.com/Tripp-Lite-Isolation-Transformer-Outlet/dp/B00006HPFH

 

If not, would you recommend something?

Thanks,

Jim

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Em2016   
John, regarding an isolation transformer, something like this? https://www.amazon.com/Tripp-Lite-Isolation-Transformer-Outlet/dp/B00006HPFH

 

If not, would you recommend something?

Thanks,

Jim

 

I'm definitely not answering on behalf of John here (not at all qualified to) but I've been emailing all the worlds major iso transformer manufacturers (even medical class) and none can come close to the <<< 1pF coupling capacitance.

 

But feel free to ask around and share if you can find a current production unit like this. It would have to be an expensive custom design and customer order I would think. I THINK that's why John mentioned the Topaz is a bit of a special beast.

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Hello John and thanks for the info:

 

I have here some possible choices, i hope you can suggest if any of these are good for the job or perhaps any could do it even better:

 

Topaz Line Noise Suppression Ultra-Isolator Part# 91005-31 ~Untested~ S2453

 

 

TOPAZ 91001-12 Isolating Transformer 120V | eBay

 

 

TOPAZ ULTRA-ISOLATOR LINE NOISE SUPPRESSOR 91001-11 | eBay

 

 

 

regards

 

Miki

 

A few quick words on what is happening with the transformers I have been talking about and how to setup a system using them.

 

It starts with the leakage loops I have been talking about recently. Remember these are loops that go through the AC mains, power supplies, DC output of power supplies, interconnects (audio and digital) to other power supplies and back through the AC mains. Note this has nothing to do with the "third pin" safety ground. I've gone over this in detail in other posts.

 

You can get rid of the noise generated by these loops in two ways, block the loop somewhere in the loop (The LPS-1 does this for certain paths), OR decrease the impedance along the loop, if the impedance is lower the NOISE generated by the CURRENT will be less.

 

This post is all about the AC side of this.

 

To decrease the impedance on the AC you need to have the lowest possible amount of wire, filters, anything else between the outlets you plug your AC cords into. This specifically means NO filters in the power strips, they dramatically increase the leakage currents between boxes plugged into such a strip.

 

Ideally you should have ONE power strip with EVERYTHING in your audio system plugged into that one strip. By everything I mean everything that has an AC plug that is connected into your audio system somehow. This includes power amps, computers etc.

 

Note this is the ideal situation, try and achieve this if you possibly can. For example if you are in a 120V area and you have two 700 watt power amps you can't do that, so some other arrangement will have to be made.

 

BTW the power strip for this does not have to be very expensive. I am currently using a $35 Tripp Lite power strip, no nothing inside, circuit breaker, switch, outlets and wires. Just this alone replacing my $1000 audiophile power filtering strip made a huge improvement in sound.

 

So now you have gotten rid of those expensive filtering power strips, doesn't that leave your system exposed to all the crud on the AC line from your other deices in your house and your neighbors as well? That is where the isolation transformer comes in.

 

These transformers with the very low interwinding capacitance are VERY effective noise filters AND surge suppressors without increasing leakage currents. MANY MANY of the filtering systems in your audiophile power strips DO filter out the noise, BUT they add large amounts of leakage currents into the system. These isolation transformers block the noise without adding leakage currents.

 

So the system as a whole is the isolation transformer feeding a very simple, very low impedance power strip with everything plugged into that power strip. This gets rid of external AC mains noise, deals with surges and provides a very low impedance AC mains path that significantly cuts down on the noise from the leakage loops.

 

Note it does not decrease the actual leakage loops, they are still there, it just decreases the NOISE generated by these loops, and THAT is what really matters.

 

So devices like the LPS-1 will BREAK loops from the digital side of things, which are usually the worst ones in a system, the above AC mains topology will decrease the noise generated by the leakage loops in the rest of the system, DACs, preamps, poweramps etc.

 

John S.

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Superdad   
John, regarding an isolation transformer, something like this? https://www.amazon.com/Tripp-Lite-Isolation-Transformer-Outlet/dp/B00006HPFH

 

Hi Jim:

 

Most of the TrippLite isolation transformer units also have various additional surge-suppression devices--such as MOVs (metal oxide varistors)--which as John explained are not very desirable in out application.

 

Also, to hit the price points they do, I sincerely doubt that the inter-winding capacitance specs of the Tripp units are anywhere near as low as the old Topaz industrial units. Those Topaz units were expensive in their day.

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Superdad   
Hello John and thanks for the info:

 

I have here some possible choices, i hope you can suggest if any of these are good for the job or perhaps any could do it even better:

 

Topaz Line Noise Suppression Ultra-Isolator Part# 91005-31 ~Untested~ S2453

 

 

TOPAZ 91001-12 Isolating Transformer 120V | eBay

 

 

TOPAZ ULTRA-ISOLATOR LINE NOISE SUPPRESSOR 91001-11 | eBay

 

 

 

regards

 

Miki

 

Hi Miki:

 

The first one you linked to a very large 5KVA unit, where as the other two are a more manageable size 1KVA.

 

When buying these used (the only way they come!), pay attention to the cords and outlets as most of the time they are cut, and you will have some work to properly wire them.

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I'm definitely not answering on behalf of John here (not at all qualified to) but I've been emailing all the worlds major iso transformer manufacturers (even medical class) and none can come close to the <<< 1pF coupling capacitance.

 

But feel free to ask around and share if you can find a current production unit like this. It would have to be an expensive custom design and customer order I would think. I THINK that's why John mentioned the Topaz is a bit of a special beast.

 

The direct descendant of the Topaz is the Eaton Power-Suppress 100 series. They are the same transformer but enclosed in a rectangular metal box. They are in current production and several online companies sell them. They are not cheap ($600 range) but are brand new. If you want ones that plug into an outlet and have its own outlets make sure do NOT get a hardwired version. You can get both types, but a couple places just have the hardwired versions.

 

Ebay has a couple used ones.

 

John S.

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Andyman   

Ideally you should have ONE power strip with EVERYTHING in your audio system plugged into that one strip. By everything I mean everything that has an AC plug that is connected into your audio system somehow. This includes power amps, computers etc.

 

John S.

 

...what about ethernet switch, router, TV screen (HDMI'd to computer)?

 

(This power strip's getting quite big!)

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...what about ethernet switch, router, TV screen (HDMI'd to computer)?

 

(This power strip's getting quite big!)

 

This is where you have to think about where leakage loops can happen. If a loop cannot happen, then you don't need a low impedance AC connection.

 

For example if the switch is connected via Ethernet cable that does NOT connect the shield, then you cannot get a loop through it so it does not need to be on the same strip.

 

If the TV is connected via HDMI to a computer and you have a USB connection from that computer to your DAC, then you definitely have a loop through the TV so it should be on the same strip. If you use a USB isolator (such as Intona) which blocks the loop over the USB then you can't get a loop from the computer so the TV doesn't matter.

 

This is one of the reasons that dedicated headless computers, streamers etc are popular, if their connection to the outside world is an Ethernet connection (without connected shield) that computer is the only part that needs to be part of the "all in one" strip.

 

John S.

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JHG   
The direct descendant of the Topaz is the Eaton Power-Suppress 100 series. They are the same transformer but enclosed in a rectangular metal box. They are in current production and several online companies sell them. They are not cheap ($600 range) but are brand new. If you want ones that plug into an outlet and have its own outlets make sure do NOT get a hardwired version. You can get both types, but a couple places just have the hardwired versions.

 

Ebay has a couple used ones.

 

John S.

 

Thanks John. Not sure what VA capacity I need. I have a turntable, CD Player/Transport, Network Player, DAC, Preamp, 2 mono amps, urendu, USB?SPDIF Converter. Any recommendation?

Thanks, Jim

 

Eaton Power-Suppress 100 Model Selection Guide

 

[TABLE=class: dataTable, width: 715]

[TR=class: center]

[TD=class: TableHead, bgcolor: #0067C3]Part Number[/TD]

[TD=class: TableHead, bgcolor: #0067C3]Input voltages1[/TD]

[TD=class: TableHead, bgcolor: #0067C3]Output voltages1[/TD]

[TD=class: TableHead, bgcolor: #0067C3]Output VA2[/TD]

[TD=class: TableHead, bgcolor: #0067C3]I/O interface (NEMA)[/TD]

[TD=class: TableHead, bgcolor: #0067C3]H x W x D, (in)[/TD]

[TD=class: TableHead, bgcolor: #0067C3]Weight (lb)[/TD]

[/TR]

[TR=bgcolor: #E8E8E8]

[TD=class: TableHead, bgcolor: #0067C3, colspan: 7]Line-cord/receptacle models[/TD]

[/TR]

[TR]

[TD]T100R-0500[/TD]

[TD=class: center]120[/TD]

[TD=class: center]120[/TD]

[TD=class: center]500[/TD]

[TD=class: center]5-15P / (1) 5-20R2[/TD]

[TD=class: center]6.49 x 6.10 x 12.00[/TD]

[TD=class: center]22[/TD]

[/TR]

[TR=bgcolor: #E8E8E8]

[TD]T100R-0750[/TD]

[TD=class: center]120[/TD]

[TD=class: center]120[/TD]

[TD=class: center]750[/TD]

[TD=class: center]5-15P / (1) 5-20R2[/TD]

[TD=class: center]6.49 x 6.10 x 12.00[/TD]

[TD=class: center]28[/TD]

[/TR]

[TR]

[TD]T100R-1000[/TD]

[TD=class: center]120[/TD]

[TD=class: center]120[/TD]

[TD=class: center]1000[/TD]

[TD=class: center]5-15P / (1) 5-20R2[/TD]

[TD=class: center]6.49 x 6.10 x 12.00[/TD]

[TD=class: center]31[/TD]

[/TR]

[TR=bgcolor: #E8E8E8]

[TD]T100R-1800[/TD]

[TD=class: center]120[/TD]

[TD=class: center]120[/TD]

[TD=class: center]1800[/TD]

[TD=class: center]L5-20P / (2) 5-20R2[/TD]

[TD=class: center]10.49 x 11.10 x 17.00[/TD]

[TD=class: center]54[/TD]

[/TR]

[TR]

[TD]T100R-2400[/TD]

[TD=class: center]120[/TD]

[TD=class: center]120[/TD]

[TD=class: center]2400[/TD]

[TD=class: center]L5-20P / (2) 5-20R2[/TD]

[TD=class: center]10.49 x 11.10 x 17.00[/TD]

[TD=class: center]58[/TD]

[/TR]

[/TABLE]

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Superdad   
Thanks John. Not sure what VA capacity I need. I have a turntable, CD Player/Transport, Network Player, DAC, Preamp, 2 mono amps, urendu, USB?SPDIF Converter. Any recommendation?

Thanks, Jim

 

Hi Jim:

 

90% of your choice will be based on the draw of your power amps. Without the power amps you easily get away with a 500VA unit. Depending upon the size of your amps, even 2400VA could end of not being enough--or it could be plenty.

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flkin   
The direct descendant of the Topaz is the Eaton Power-Suppress 100 series. They are the same transformer but enclosed in a rectangular metal box. They are in current production and several online companies sell them. They are not cheap ($600 range) but are brand new. If you want ones that plug into an outlet and have its own outlets make sure do NOT get a hardwired version. You can get both types, but a couple places just have the hardwired versions.

 

Ebay has a couple used ones.

 

John S.

 

Why not the hard wired version?

 

Also the Easton spec sheet says Impedance of 3-6%. What does this mean? Sounds rather high...

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Why not the hard wired version?

 

Also the Easton spec sheet says Impedance of 3-6%. What does this mean? Sounds rather high...

 

The hardwired versions work fine, I just want people to know what they are getting. The hardwired versions don't have a plug or outlets, just standard holes to mount conduit or BX etc. I don't want someone to spend the money to get one and find out they can't use it.

 

I'll have to spend some time looking at that spec, off the top of my head I have no idea what it means. The only thing that comes to mind might be something like power factor, but that is not usually speced that way.

 

John S.

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ted_b   
.......but as we have been saying, the evil of an SMPS is not the ultra high-frequency harmonics (spread over a very wide bandwidth to pass strict emissions requirements)--heck, all conventional LPS units kick a lot of low frequency harmonics into the line. No the evil of an SMPS is its passing of AC leakage currents (onto the DC) and the formation of "leakage-current-loops" with other power supplies (LPS or SMPS) in one's system.

 

Since the UltraCap™ LPS-1 100% blocks leakage currents from whatever supply is feeding it (LPS feeders have leakage too, just not as much as an SMPS with its required "Y" capacitor), the SMPS is rendered harmless. Does the wall wart on your telephone or answering machine do sonic detriment to your audio system? That's about the relationship that an LPS-1 feeder has to your system.

 

--Alex C.

 

Alex/John,

Hi. I am looking to get an LPS-1 into my system, likely to simply power the microRendu (instead of my JS-2, which I will solely use elsewhere in the system using only a single rail). My question is regarding your phone/answering system example (quote taken from another thread). And before I go on, I realize the LPS-1 is literally immune and isolated from this example, but a dirty wallwart is nonetheless leaking into the mains. Most people's dirty wallwarts within their home are hopefully not in the listening room and likely not on the circuit used for audio. I (ignorantly) assume that dirty wallwarts in the listening room's circuit are more likely to affect hearing that noise than when placed elsewhere in the house, so is your example relevant? Seriously, I ask ignorantly cuz I know 'everything matters" but if I am to worry about the whole house (and I do have whole house surge protection and ground loop protection installed at the mains box), then my first work would be with my refrigerator.

 

Anyway, what I am trying to ask is that is it worth it to use your included SMPS (or any other cleaner wallwart) on another circuit other than the audio one (solution in most people's homes would be a 25 ft extension cord to closest non-audio circuit)? If not, is it because all circuits would affect sq the same (which in your estimation, with the LPS-1 design, is almost nill anyway)? Thx

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Alex/John,

Hi. I am looking to get an LPS-1 into my system, likely to simply power the microRendu (instead of my JS-2, which I will solely use elsewhere in the system using only a single rail). My question is regarding your phone/answering system example (quote taken from another thread). And before I go on, I realize the LPS-1 is literally immune and isolated from this example, but a dirty wallwart is nonetheless leaking into the mains. Most people's dirty wallwarts within their home are hopefully not in the listening room and likely not on the circuit used for audio. I (ignorantly) assume that dirty wallwarts in the listening room's circuit are more likely to affect hearing that noise than when placed elsewhere in the house, so is your example relevant? Seriously, I ask ignorantly cuz I know 'everything matters" but if I am to worry about the whole house (and I do have whole house surge protection and ground loop protection installed at the mains box), then my first work would be with my refrigerator.

 

Anyway, what I am trying to ask is that is it worth it to use your included SMPS (or any other cleaner wallwart) on another circuit other than the audio one (solution in most people's homes would be a 25 ft extension cord to closest non-audio circuit)? If not, is it because all circuits would affect sq the same (which in your estimation, with the LPS-1 design, is almost nill anyway)? Thx

 

Hi Ted,

it's a question of degree. In most systems the sonic detriment from leakage current is much worse than the detriment from actual noise on the mains (noise between neutral and hot). If you DO get rid of the leakage loops, then issues relating to actual noise on the mains may have some small impact. The isolation transformers mentioned above will essentially eliminate any noise from the rest of your house getting into the audio system AC mains AND provide very good surge protection.

 

But even if you don't use the isolation transformer the actual amount of noise injected back into the mains from modern SMPS is pretty small. I did some tests of this recently and could not see ANY difference in the noise on my mains from the Mean Well SMPS. BUT the SMPS that came with my older headphone amp was a different story, it was bad. For some reason the SMPS from older networking equipment seems to be particularly bad.

 

So if worried about any of this, just use the isolation transformer on the circuit used for the audio system and that will make sure none of the noise from the rest of the house gets into the audio system.

 

John S.

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Why not the hard wired version?

 

Also the Easton spec sheet says Impedance of 3-6%. What does this mean? Sounds rather high...

 

The impedance as a percentage relates to the increase in impedance brought about by the transformer. Thus whatever the impedance was of the line going into the transformer, the output impedance is that plus 3-6%.

 

Since isolation transformers are 1:1 devices, ideally out would be the same as in, but transformers are never completely lossless, so in order to have the same output voltage as input they have to make the ratio slightly different, such as 1:1.05 to deal with the transformer losses. This ratio gives a slightly higher output impedance than the input.

 

John S.

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John

I have these connected to my mains box. Is this relevant?

http://ep2000.com/uploads/EP-2050_SeriesSpecifications.pdf

http://ep2000.com/uploads/EP_Ground%20Filter.pdf

 

If not, where do the receptacle Eaton boxes go? In the audio circuit or anywhere BUT the audio circuit?

 

How are these devices hooked up? Between the power company feed and everything in your house, or just on the wires feeding the audio system? If they are just on the audio system wiring then they are already doing some cleanup of anything coming from the rest of the house. But they are only good from 3KHz and up whereas the isolation transformers are good from 400Hz and up. That can make a big difference to an audio system.

 

So using the isolation transformer is still a good idea, it would still go between the wiring in the walls and the power strip where all the equipment is plugged in. So if using the one with plugs and outlets, plug the isolation transformer into the wall, and plug your power strip into the transformer.

 

The surge suppression techniques used by the device above and the isolation transformer are different, they work very well together, complementing each other.

 

John S.

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ted_b   

They are hooked between outside power feed and whole house. I will examine my VA needs and look into the receptacle Eatons, thanks. BTW, I usually have an almost vacuum-like silence on my audio ac, but a pair of wonderful sounding (but unshielded) interconnects tend to absorb any meanies floating around, so I am susceptible.

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jamesg11   
Yes my Topaz hums a little, it is an acoustic Hum (the output is 60Hz AC which of course is the ultimate hum!). I built a box around it with some pillows for now. It does get a little warm so you have to be careful with thermal management.

 

Without the box I can hear it when I am standing near it, from the listening position I can just barely hear it with no music playing at 3AM when the house is very quiet. The refrigerator running a couple rooms away is much louder.

 

John S.

From the Eaton 100-Suppress Tech Sheet -

 

"Audible noise: Less than 50 dBA measured at 3 feet from the noise suppressor".

Hmm, my listening noise floor is ~35dBA. //& no next room possible, so box & pillows coming up!

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Em2016   
From the Eaton 100-Suppress Tech Sheet -

 

"Audible noise: Less than 50 dBA measured at 3 feet from the noise suppressor".

Hmm, my listening noise floor is ~35dBA. //& no next room possible, so box & pillows coming up!

 

Hey mate, are you planning on getting a Topaz too or the Eaton? I hadn't see any Eaton's available in Oz but could be wrong.

 

I've got my Elgar on the way as well as my LPS-1 next month. Can't wait!

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Hello,

 

I am considering what John suggested i just don't know if these choices would serve the purpose and if, which can be the best choice:

 

It will be: Wall - Transformer - Strip - all system including Microrendu with LPS-1, Preamp, 200w Amp, DAC, MacMini, OPPO player and perhaps TV

 

Choices that i am believing are the ones John mentioned:

 

UPS & Uninterruptible Power Supplies | Eaton Power-Suppress 100 1kVA 120/240V In 120/240V Power Conditioner

 

TOPAZ 91001-12 Isolating Transformer 120V | eBay

 

Regards

 

Mike

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jamesg11   
Hey mate, are you planning on getting a Topaz too or the Eaton? I hadn't see any Eaton's available in Oz but could be wrong.

 

I've got my Elgar on the way as well as my LPS-1 next month. Can't wait!

Well, I was going to ring Eaton Australia & see if they stocked or could get one here - no idea of cost. Their website is hopelessly opaque / all over the place! But iso transformer is on product lists at 240V.

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