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Isolation Transformer


cazzesman

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After having some recent issues with some unknown interference in my audio system, I spoke with a few friends on SNA.    The issues now appears to have disappeared but it involved clicks and a sound like 'Sizzling bacon' coming through the speakers.   The suggest was it was some form of Earth/Ground Loop interference.

 

I learnt about Isolation Transformers during my discussions and subsequent Google searches.  This Hobby virtually dictates we are constantly trying new stuff, so I thought, 'what the heck!'.

As a result I have taken the plunge and decided to give an IsoTran (I've even learnt the lingo) a go in my audio system.

 

There is some great discussion in this Link.........

https://www.computeraudiophile.com/forums/topic/29662-discussion-of-ac-mains-isolation-transformers-started-wposts-moved-from-quotlps-1-troubleshootingquot-thread/

 

Upon a recommendation (SNA member who uses this brand) I made a purchase of a brand called 'Block' from Germany - Model STEU 2000/23.  It is 2000 VA Rated.     Delivery date is approx 5th January.

 

http://www.farnell.com/datasheets/1822338.pdf?_ga=2.148115761.785914256.1545615461-834991493.1545203395

 

The Unit is EI-Core.   Is it overkill at 2000VA?     Maybe but I guess it is somewhat future proof.  I don't intend to run my Active SGR's off the IsoTran.    I will be running my DAC/Pre, TV, Oppo Bluray, Mutec and Mini Headless Audio PC.

 

The unit dimension is 192 w x 192 d x 180.5 h.    It weighs in at 25.5 kg.   For the sake of safety I required a box to put it in so I decided to use what I had around home and go the DIY route.

I am no fine craftsman but I have the tools to get buy.   Besides, it would be hidden behind the stereo cabinet so if it was an eyesore, no harm done.

 

For the sake of ease I made the internal dimensions of the box 250 x 250 x 250.   I'm not sure how much heat the unit will generate so I have given it some breathing space and large ventilation windows.

 

The box has a lift off lid for easy access to the cable connectors.    The actual box also lifts off from the base once a few screws are removed.    I thought if I need further ventilation I can remove the lid and place some form of rigid metal mesh in-situ.

 

I have a cable with a 3 pin plug ready to attach to the IsoTran.  That cable will connect to the home power socket.   I also have a female 3 pin Plug Base ready to attach, whereby a 4 or 6 socket power board can be plugged in. 

 

The box is now done and awaits the contents to arrive.    And NO I will not being doing the connecting.  A suitably experienced gent in the field of Electricity will undertake that task.

I will take some more snaps during the installation progress and let you know if it ends up being snake oil or the good oil.

 

Regards Cazzesman

 

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Edited by cazzesman
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Thanks Dave,

 

I have changed nothing in my Audio Pc into the Mutec via USB and yet the sound has now gone.

 

I have no idea why the issue has come and gone but for the time being all is right with the sound.

 

Regards Cazzesman

 

 

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Just a few things to keep in mind.

 

Be sure to extend the protective earth (yellow/green) wire from the incoming side to the outgoing side.  That way the integrity of the protective earth remains viable.

 

If it was me I'd wire a 10A circuit breaker to the active wire on the primary side just in case of an overload or fault.  You don't want the transformer catching on fire in your absence, especially in a combustible dry wooden box. The other thing I'd add is a RCD (Residual Current Device) to the secondary side of the transformer.

 

Additional food for thought:  This is obviously a DIY project (which I'm sure many on SNA get involved in wiring things on the mains supply side of the device), but please, please, please bear paramount in your mind - SAFETY and, LIABILITY if something goes horribly wrong.

 

If the device catches fire and burns your house down I seriously doubt if insurance would cover you for a device not wired up by a licensed electrician.  The transformer itself may be compliant although I could not find that specific model on the element14 Australian website (Element14 = Farnell in Australia).  However simply because they don't stock it doesn't necessarily mean it's not compliant.

 

The other more serious concern is accidental electrocution.  By adding an isolation transformer you are effectively bypassing the RCD (Residual Current Device) in your switchboard for those devices connected to the secondary side of your isolation transformer, thereby risking potential electrocution from any of the devices connected to the secondary of the transformer in the event of a fault.  If someone gets injured or dies from electrocution from operating or touching any of the devices connected to the secondary you can be expected to be charged with attempted manslaughter for the former and manslaughter for the latter.

 

Don't want to be a killjoy but I don't want to read sometime down the track that someone's house burned down or someone got seriously injured or killed.

 

At a minimum (unless you are an appropriately licensed electrician) get an experienced qualified electrician to double check your work and if possible certify that I has been correctly wired up.  Affix the appropriate electrical stickers and here's a hint - fit some hinges and some sort of lock to the removable lid.  Curious little fingers come to mind.

 

Good luck with the project.

 

Cheers,

Alan R.

 

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Thanks Alan R,

 

Greatly appreciate your thoughts, hints and concerns.

 

Had a fellow SNA DIY gent over this morning and he wired the unit up for me.   He has had the identical Unit for some period.    Multi-metered and triple checked over in use before placing in situ.

 

You can see in the last image the Earth is combined from both sides.

 

I Like the idea of the 10Amp Circuit breaker inserted.   After being plugged in for 4 hours I'm keeping and eye on the units temp.  So far so good.  It is warm to the touch but the vents seem to be doing the trick.    As I mentioned, I can replace the timber lid with an open mesh metal lid if more ventilation required.    No little fingers in the house so all good there.

 

At this stage I have a 4 bank power board attached; running Pre/Dac, Mutec, Plasma TV and Mini PC.

 

I will let you know the SQ results once it has all settled down.   Thanks again Alan R.

 

Regards Cazzesman

 

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On ‎24‎/‎12‎/‎2018 at 11:16 AM, cazzesman said:

The box is now done and awaits the contents to arrive.    And NO I will not being doing the connecting.  A suitably experienced gent in the field of Electricity will undertake that task.

I will take some more snaps during the installation progress and let you know if it ends up being snake oil or the good oil.

 

Regards Cazzesman

 

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Good to read that you are getting the important stuff done by a qualified person.  :) 

 

My comments in my previous posts were generic and not all specific to your project.

 

BTW, nice box.  I would assume the WAF / PAF would be high.  No one would guess there's a transformer hiding in there.  :)

 

Cheers,

Alan R.

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4 minutes ago, cazzesman said:

Thanks Alan R,

 

Greatly appreciate your thoughts, hints and concerns.

 

Had a fellow SNA DIY gent over this morning and he wired the unit up for me.   He has had the identical Unit for some period.    Multi-metered and triple checked over in use before placing in situ.

 

You can see in the last image the Earth is combined from both sides.

 

I Like the idea of the 10Amp Circuit breaker inserted.   After being plugged in for 4 hours I'm keeping and eye on the units temp.  So far so good.  It is warm to the touch but the vents seem to be doing the trick.    As I mentioned, I can replace the timber lid with an open mesh metal lid if more ventilation required.    No little fingers in the house so all good there.

 

At this stage I have a 4 bank power board attached; running Pre/Dac, Mutec, Plasma TV and Mini PC.

 

I will let you know the SQ results once it has all settled down.   Thanks again Alan R.

 

Regards Cazzesman

 

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Nice.  :)

 

Cheers,

Alan R.

 

 

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Well after 3 hours of listening I am 100% convinced the IsoTran is the greatest thing since sliced bread.  ?    Yes I am excited!!!!!

 

The effect it has had on my system is easily discernible.    All the olde audio cliches; blacker background, gauze lifted, scale, speed, precision, depth and an improvement in the natural richness of the overall sound.     Listening to Devin Townsend's 'Truth' from his 'Transcendence' CD was stunning.   I had finally arrived at his revered 'Wall of Sound'.  All 9' x 11' of it.   WOW! 

 

My SNA friend who recommended I get the Unit said to me, and I paraphrase, 'Once you go Isotran, you never go back!'    I now know exactly what he was saying.    Can't wait to hear how it sounds once it has been baking for 100+ hours.

 

Thanks Cobber. ??

 

Regards Cazzesman

 

 

 

 

 

 

 

 

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Hi Skies,

 

The Unit was recommended to me by a fellow SNA member.     He has several in his system including this model.     I knew nothing about them until being bought up to speed regards their usage in audio.

 

I did some research and it is a highly regarded brand from Germany.

 

Regards Cazzesman

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On 24/12/2018 at 1:16 PM, cazzesman said:

... For the sake of safety I required a box to put it in so I decided to use what I had around home and go the DIY route.

I am no fine craftsman but I have the tools to get buy.   Besides, it would be hidden behind the stereo cabinet so if it was an eyesore, no harm done...

 

On 30/12/2018 at 1:16 PM, Monkeyboi said:

... and here's a hint - fit some hinges and some sort of lock to the removable lid.  Curious little fingers come to mind...

 

On 30/12/2018 at 1:53 PM, cazzesman said:

... No little fingers in the house so all good there....

 

An interesting project.  Pleased to hear it's improved your sound. 

 

Some thoughts regarding safety.  You mention that when finished you are going to hide this behind the stereo cabinet.  It is very likely that once the project's finished and it's located there that you will then put it out of mind.  And not think about it the time when some little fingers do appear in your house (eg. on a visit with their parents). 

 

Little people are curious, and like to go exploring in places that adults don't (eg. behind stereo cabinets),  especially when not supervised.  The cabinet looks nice, however those ventilation slots are very large - a little hand could go in there, or poke something conductive into it.  It certainly wouldn't pass AS/NZS safety standards.  I would suggest looking for some metal mesh to securely fix to the box, as well as fixing the top. 

 

 

Edited by audiofeline
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I love the use of blue wire to link the to earth wires together.

No way would any electrician take offence to that.

 

(Sarcasm)

 

As said above, mdf enclosure, large holes for fingers, easily removed lid.

Nope. I have no issues with that build at all.....

Edited by Witchcraft
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Beautiful stuff and I realise you have put a lot of effort in, but here are a few of my observations and suggestions.   (I don;t mean to be a killjoy here, but just to offer another opinion)

 

Just to state:- I have been known to do a few shortcuts in my diy past.  However, anything less than 100% safe with mains is just inviting trouble.  Run with the motto "if it can go wrong it will" and you will be fine.

 

I have to agree with Witchcraft,  Blue for Earth hookup is just a BIG NO!!!


Get rid of that wooden box!!!

Put your hand in your wallet and go buy/ get made a new steel case to fit your beautiful tranny in.

Steel will not burn your house down!  And make the case bigger so the tranny can breathe.

 

Space the feet of the tranny 25mm off the bottom of the case and have vents on at least all four sides.

The lid MUST be screwed on at all times.  How would you feel if while you were not at home and someone else's visiting kid died because you had the lid off or not secured?

 

I would put feet on the bottom of the metal case too, so it is clearly 25mm off floorboards and carpet.

 

Someone else suggested the use of a contactor/fuse on the input  - a great idea

They also suggested an RCD on the secondary  - absolutely too.

 

I'd use better mains cable and plugs than what you have found in your scrap box.

No, $300/m audiofool cable is not required, but just something a little nicer quality and heavier gauge than what your mate used.  I like Clipsal 56Series male plugs and Furutech female units.

 

I have a 13A isolation tranny (weighs 44kgs) similiar to yours that I am keen to get into my system soon and I totally understand your enthusiasm!  Alas, I need to do all the above too before I can fire it up, as the prospect of sharing a cell with Big Bubba or the thought of losing my home to lawyers is one I will not make...


 

 

 

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23 hours ago, Witchcraft said:

I love the use of blue wire to link the to earth wires together.

No way would any electrician take offence to that.

 

(Sarcasm)

 

As said above, mdf enclosure, large holes for fingers, easily removed lid.

Nope. I have no issues with that build at all.....

I am listening to and taking onboard all the advice I have received here on this thread.  99.9% is extremely constructive and well detailed.

 

If you just want to come across as an arrogant know it all, then please take your thoughts elsewhere because there are plenty of others who can and do get their point across without the need to be 'holier than thou'.

 

Regards Cazzesman

 

Edited by cazzesman
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Thanks to all those who have offered some very constructive, professional advice on my project.

 

I have now purchased a suitable, lockable metal box, some metal vents, 15 amp power cable and am in the process of purchasing the appropriate circuit breaker etc.   Once it all up to speed I will have it signed off by a qualified electrician.

 

I now consider my timber box a 'Proof of Concept'.  ?

 

The concept of improved SQ certainly works, so I will heed all advice and make good on rectifying the safety issues that have been raised.

 

Thanks again to all with concerns.

 

Regards Cazzesman

 

 

 

 

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Guest rmpfyf

Consider how anything connected could register/clear a fault (not sure if this is balanced, but either way there’s a few caveats).

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For those playing at home who are vaguely interested, here is the latest information obtained from a qualified Victorian electrician.

 

The unit is deemed to be a stand alone device and as such does not require a ‘Certificate of Compliance’ from an Electrician.       In a perfect world it should be wired by an electrician but as long as it is wired and then ‘ tested and tagged’ by a qualified official ‘tester and tagger’ then that is all the documentation that is required for insurance purposes.

 

The unit will require a 10amp RDC breaker positioned between the 240 power cord and the input into the Isotran i.e. the orange input as per the above images.

 

The circuit breaker is to be placed inside the lockable box.

 

Regards Cazzesman

 

 

Edited by cazzesman
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Guest rmpfyf
36 minutes ago, cazzesman said:

The unit will require a 10amp RDC breaker positioned between the 240 power cord and the input into the Isotran i.e. the orange input as per the above images.

 

That RCD will clear a fault into the transformer - how do you detect/clear a fault on the downstream side of the trans?

 

Will depend on the design of your trans and other factors. Best check.

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?? rmpfyf.

 

I have just finished a ph conversatio  with my bro who is abit of a diy wiz with electronics.   He said the very same thing.

 

As he said..........   There is enough safety on the input side of the isotran with a 10amp breaker and rcd on the house switch board.   It is no different to plugging the toaster in.    If the toaster is faulty the breaker kicks in and rdc saves you if required.

 

The issue of safety is on the output side where you need the rcd as the isotran effectively takes the switchboard rdc out of play.     As mentioned by a few above the rdc on the output side is the no-brainer re safety.

 

The research goes on it seems.    Even Electricians get confused it seems.    At least the ‘Test and tag’ situation is easier to sort as we have one where I work.

 

Regards Cazzesman

 

 

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Guest rmpfyf

Cazz

 

Can't give advice here (no one can) as you are operating in a legally liable manner, I haven't seen your kit and I am not a licensed tradesperson to this end, though I would suggest that some requirements for isolation transformers are covered under AS 3000:2018 depending how your transformer is connected. Requirements cite a circuit-breaker acting on all live circuits or a high rupturing capacity fuse on all actives. There are also requirements around earthing multiple socket connections on the load side. 

 

In short, I would get a copy of the Standard as a minimum. A RCD on the output (load) side won't suffice. 

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Rmpfyf,

 

Your thoughts on the AS 3000 are worth while but if two Certified Electricians can’t agree then we are all doomed.

 

1 has said set cb/rcd on input to isotran and 1 says set up cb/rcd on output side which makes far more sense to me.   

 

What’s the old story about how a zebra was created.    They asked 10 people their opinions on how to create a racehorse and after months of discussion and workshopping they ended up with the zebra.  ?

 

Regards Cazzesman

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Guest rmpfyf

@cazzesman@rocky500 I get that 'RCD = good', though (a) that's not code, and (b) in a balanced isolation transformer where your earth no longer leaks to ground, I'm not sure your RCDs will work. Actually I'm pretty sure they won't. In the event of an issue, you conduct to ground. There is no earth leakage to detect in a balanced isolation transformer, though that 'test' button may generate one locally that trips the sensing circuit. 

 

Definitely not for a balanced isolation, not sure what you have Cazz.

 

You will need better sensing. 

 

I would not expect domestic sparkies to know all of AS 3000 backwards for every application. It's a long standard.

 

Last time I looked at this I was suggested an insulation monitoring device though I'd insist you undertake to get independent advice from a power systems specialist. 

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19 minutes ago, rmpfyf said:

@cazzesman@rocky500 I get that 'RCD = good', though (a) that's not code, and (b) in a balanced isolation transformer where your earth no longer leaks to ground, I'm not sure your RCDs will work. Actually I'm pretty sure they won't. In the event of an issue, you conduct to ground. There is no earth leakage to detect in a balanced isolation transformer, though that 'test' button may generate one locally that trips the sensing circuit. 

 

Definitely not for a balanced isolation, not sure what you have Cazz.

 

You will need better sensing. 

 

I would not expect domestic sparkies to know all of AS 3000 backwards for every application. It's a long standard.

 

Last time I looked at this I was suggested an insulation monitoring device though I'd insist you undertake to get independent advice from a power systems specialist. 

This is what is wriiten on their webisite. So thought I would put them on. LINK

 

"

ONE IMPORTANT THING TO NOTE

RCDs (Safety Switches) are only effective if they are plugged into the supply. Safety switches on your main switchboard will NOT protect equipment connected to the power supply. We recommend you use an appropriate safety switch on the power supplys output socket."

 

Edited by rocky500
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