Tripp Lite IS250 Review (Isolation Transformer)

[DualTriode]

This is not directly connected to the reviewed product, but is there a clear difference between consumer-grade isolation transformer and medical-grade isolation transformer? is one made of higher quality components while the other isn't?
A quick surf on the internet shows me various pricing of those products, some are considerably more expensive than others while having identical specs.

The "real" medical grade isolated power as in OR's, procedure rooms and catherization / radiology labs ect. is isolated.

Both conductors are considered hot. Neither conductor is connected to ground. No current will flow if either hot conductor goes to ground.

If you really want to know.

Isolated Power Systems – Common Questions & Answers - Isolated Power Specialist

Sometimes, a simple "question & answer" approach can bring clarity to a complicated subject. Perhaps this list of IPS questions & answers will be helpful.

www.isolatedpowerspecialist.com

 

[laudio]

I've known folks where these devices help at low cost. Not so much on Amir's limited test bench. Most desktop jockeys on this site wouldn't know when if/matters who are commenting.

This isn't PS Audio asking $5k for something, it's Tripp Lite lol. What's with the ASR attitude?

 

[KSTR]

This thingy is an isolation transformer and does what does, isolate the L and N lines, achieving a high common-mode impedance at mains frequencies (apart from coupling via capacitive inter-winding capacitance when there is no secondary shield winding connected to PE).
There are audio application what will improve from that, no doubt, though limited.

However, it is not a safety isolation transformer for laboratory or industrial use where PE is disconnected and where you must put only one single device at the output so that the equipment is fully floating. The better safety isolation transformer have shield windings on both primary side and secondary side. Primary side shield goes to PE and secondary side shield is accessible with a binding post.

 

[Katji]

LOL First time I've seen this praying Pink Panther.

 

[sq225917]

I like the tests Amir does on audio products, it's a great service for us all.

But I struggle with the provided value and optics of testing otherwise proven, none audio devices, in off piste, audio applications.

I understand the education side of it, highlighting that using a device to do something it isn't designed to achieve isn't a likely path to success, and therefore helps reduce the myth and mistake surrounding accessory usage but the problem is that it sometimes comes across as gleeful slating. And that doesn't help the credibility of the site and opens the site up for wider criticism of all process and test suitability.

Might I suggest an 'off piste corner' where popular none audio intended devices that get audio approval when used outside their Intended reason d'etre might be found.

Better still, if you test anything in a common off-label use also test its on-label use. Ie this is a great common mode noise removal tool, but does SFA when used as 99% of audiophiles install it.

I'm sure I'm not the only one who feels disappointed in the site when he reads tests like this, which are obviously incomplete?

 

[Lambda]

The schematic above is incorrect as there is no capacitor paralleling the diodes, but a 1/2W or 1W resistor. (It can't be discerned from the image and there is no mention of the value or power rating of the resistor.) There is no fuse. There is an LED with a resistor across the incoming 120VAC input connector to tell you that the device is armed and ready to go up in smoke.

Cool. but i don't think you get the point.
Never Claimed this is the exact complete schematic of the commercial device.
But it illustrates the working principle.

That it is not super save butt still sold and sill used and still helpful is part of the point.
with a proper low current fast fuse and RCD / GFCI i would even call it reasonably save.
On/behind a isolatin transformer it would even be saver since the small transformer sure current would be very limited...

There is million ways to make it Saver but the point was there are ways to make it and still seemingly legally sell it in the US.

This thingy is an isolation transformer and does what does,

I can't believe people are still arguing abut this.
Of cause it is and it works exactly as advertised.

Many audio devices are Class II or double insulated. the transformer would work fine with hem and Lowe leakage current and capacitance.

 

[amirm]

Many audio devices are Class II or double insulated. the transformer would work fine with hem and Lowe leakage current and capacitance.

Nonsense. Only a small fraction of audio devices are class ii.

 

[amirm]

I can't believe people are still arguing abut this.
Of cause it is and it works exactly as advertised.

No it doesn't. It is not 100% isolated as the company claims. There are a ton of Amazon reviews complaining about this fact.

Here is the very first review:

"If your looking for a test bench isolation transformer to effectively isolate a device under test while probing with an oscilloscope this particular transformer will need some modification. Notice the grounded neutral on the isolated output neutral? This will need to be removed, else you still have a path to ground even though the hot and neutral are isolated from the line. "

Here is the second review with one star rating:

"This is an "Isolation Transformer- Based Power Conditioner", NOT an isolation transformer!"

You really have no idea what you looking at and the market for it.

 

[kongwee]

Ground or no ground are for safety reason. They have to be used as such. It is your own risk to get shock if you don't comply to it. When it happen you just can't blame anyone. You have only one life.

 

[DWI]

That's all the options you could come up with? It can't be that the devices can't or won't improve your audio performance based on simple knowledge of engineering of audio design? Talk about asking permission to put your head in the sand.....

No, in my experience it can't be that all power products are of no benefit, because I've used power products, and still do, that do make a positive difference. I named one - the iFi Powerstation. You seem to like some of their products, they certainly seem to make popular DACs and power products. Basic product protection and filtering is not a new marketing-driven thing, I've had an Olson Sounds Fantastic block for 25 years, it's been in production for 50 years. I use it for my AV and am wondering if it can be improved for that function.

 

[Lambda]

Nonsense. Only a small fraction of audio devices are class ii.

Even if this would be true*. and? there are lots of turntables with cass2 and they are especially sensitive to leakage currents.
(*It is not by number must audio devices/music players today are USB powered.)

No it doesn't. It is not 100% isolated as the company claims.

they claim on the power lines. its all explained in the manual / description. there is no supriese here like with the PS audio power ting.

How would you call this device?

There are a ton of Amazon reviews complaining about this fact.

Here is the very first review:

Are you mistaking Amazon reviews an article description or marketing claims?!
I can show you amazon reviews for Salt (pure NaCl for ion exchanger regeneration) complaining it dissolves to fast in water.

If you think the company is responsible for customers misinterpreting there marketing and documentation
then why don’t you see yourself responsible for readers misinterpreting your review?

your seam to be pedantic about the "100%" isolation "from the power line" claim
But on the other hand you say:

no performance improvement can be had.

Your not saying "for the most of audio devices especially for Cass 2 devices i can’t imagen how this would help. and the one test i did with the Topping D90 did not show any improvement"
So from one tested device you can say: "the data shows its 100% impossible that this could ever improve performance in every audio system"?

but if marketing says "100% isolation from the AC power line" this is a problem?

 

[oversky]

Does an isolation transformer help reducing voltage spike?
When my dish dryer is switched on,
I can hear one or two tapping from speakers.

What is Isolation Transformer? Definition, Theory & Diagram - ElectricalWorkbook

In this topic, you study Isolation Transformer – Definition, Theory & Diagram. The transformer is frequently used to isolate one portion of an electrical system from another.

electricalworkbook.com

 

[restorer-john]

Whitlock does not address what the electrical code in the EU, UK or other countries are regarding devices of this type.

Whatever he says means nothing.

A huge amount of mains powered HiFi equipment is double insulated. That means, no safety ground or earth. None. It's not rocket science here folks.

The Tripplite people know a huge amount of connected gear is also not earthed and that's why they specifically say it's fine to connect it to this isolation transformer.

Amir is just having a go at another mains device he really doesn't really undertand the purpose of. If he did, he'd not be digging himself further and further into the massive hole he's presently dug into. And I love Amir- he's a good guy. Seriously.

 

[solderdude]

This is how it is connected (without the filtering components) but the principle of operation is as shown below.

The issue Amir talks about is that on the right side neutral and ground are connected.
This means the output voltage is not floating (as in a safety transformer).
With a safety transformer the connection between AC neutral and ground (safety ground) is not there (and probably also not the safety ground).
With this device the output voltage is still referenced to ground so when touching the AC hot you will get the same jolt as you would when touching mains.

The output voltage thus is referenced to safety ground (just like normal mains is) but the mains voltage itself is isolated.
Any DC, hot-neutral swaps on the input and leakage currents as well as voltage differences between neutral and safety ground are removed.
Ground is still connected though and when a ground loop is present due to a safety-ground path then this isn't solved.

In order to make the output like a safety transformer one would have to open it up and remove the wire between the neutral and safety ground but still ensure the safety ground outputs are still connected to the chassis (obligatory when it has a 3 prong outlet).

 

[KSTR]

Nonsense. Only a small fraction of audio devices are class ii.

I beg do differ. Any reasonable survey would most certainly show that the vast majority of consumer HiFi devices are class-II. Exceptions being bigger tube gear, large amps, some active speakers, etc, and any items "loaned" from the balanced studio gear world. And of course ordinary PCs used to source galvanically connected USB DACs etc.
So OK, today there might be more class-I devices than in previous decades but still far from being the majority.

------------

The specs and manual of the device are IMHO sufficiently clear and this seems to be a reputed company with a wide customer base, products being distributed via Digikey and Mouser. I would assume their product fully complies to (US) electrical codes and rules, both in the implementation and the docs. They wouldn't call it isolation transformer if that were illegal or deemed as misleading, would they?

However, I would have appreciated a schematic in the spec sheet (or on the device) that makes it instantly clear that the PE is not isolated and a clear disclaimer that this is not a safety isolation transformer. At least that would have been good engineering company practice in the world I come from...

 

[restorer-john]

This is how it is connected (without the filtering components) but the principle of operation is as shown below.

The issue Amir talks about is that on the right side neutral and ground are connected.
This means the output voltage is not floating (as in a safety transformer).
With a safety transformer the connection between AC neutral and ground (safety ground) is not there (and probably also not the safety ground).
With this device the output voltage is still referenced to ground so when touching the AC hot you will get the same jolt as you would when touching mains.

The output voltage thus is referenced to safety ground (just like normal mains is) but the mains voltage itself is isolated.
Any DC, hot-neutral swaps on the input and leakage currents as well as voltage differences between neutral and safety ground are removed.
Ground is still connected though and when a ground loop is present due to a safety-ground path then this isn't solved.

In order to make the output like a safety transformer one would have to open it up and remove the wire between the neutral and safety ground but still ensure the safety ground outputs are still connected to the chassis (obligatory when it has a 3 prong outlet).

Who on earth is "spare time toy factory" and what relevance do they have to do with the Tripplite configuration?

Don't tell me you don't understand an isolation transformer's functionality like Amir, please?

 

[solderdude]

Does an isolation transformer help reducing voltage spike?

It works (a bit) because the frequency response of a transformer is limited.
High frequency spikes 'lose' the highest frequencies but spikes are still there.

The best way would be to 'clamp' those spikes near the source of the problem by using a TVS or other over-voltage protection device.
This can also be done at the receiving side.
These components do not appear to be in there.

 

[restorer-john]

I beg do differ. Any reasonable survey would most certainly show that the vast majority of consumer HiFi devices are class-II. Exceptions being bigger tube gear, large amps, some active speakers, etc, and any items "loaned" from the balanced studio gear world. And of course ordinary PCs used to source galvanically connected USB DACs etc.
So OK, today there might be more class-I devices than in previous decades but still far from being the majority.

------------

The specs and manual of the device are IMHO sufficiently clear and this seems to be a reputed company with a wide customer base, products being distributed via Digikey and Mouser. I would assume their product fully complies to (US) electrical codes and rules, both in the implementation and the docs. They wouldn't call it isolation transformer if that were illegal or deemed as misleading, would they?

However, I would have appreciated a schematic in the spec sheet (or on the device) that makes it instantly clear that the PE is not isolated and a clear disclaimer that this is not a safety isolation transformer. At least that would have been good engineering company practice in the world I come from...

Totally agree and the evidence shows it. Class ii really (unfortunately) is king and has been for 30 years.

Perhaps all those 2 pin IECs on HiFi gear might be a giveaway....

 

[KSTR]

In order to make the output like a safety transformer one would have to open it up and remove the wire between the neutral and safety ground

Hhm, I would only advise to do so if it is confirmed that the transformer itself is rated for class-II, double insulated.

 

[solderdude]

Who on earth is "spare time toy factory" and what relevance do they have to do with the Tripplite configuration?

Don't tell me you don't understand an isolation transformer's functionality too? Please.

Amir can actually measure if there is a connection between N out and safety ground.
Amir says there is.
That is the relevance, and as I wrote, it shows the principle of operation.

Hhm, I would only advise to do so if it is confirmed that the transformer itself is rated for class-II, double insulated.

I would advise not to do this at all. Certainly not if one doesn't understand what they are doing.
It would have to be done if the output needs to be floating (for safety reasons) and safety ground is still connected.
Of course some TVS should probably be added between AC outs and safety ground if the transformer itself is not suited for balanced out operation up to a specified amount of kV.