Tripp Lite IS250 Review (Isolation Transformer)

[BoredErica]

I'll repeat my question: if I am using balanced amp and dac with computer as the source, are there any weird ground loops, hums, noises that can manifest audibly from computer or dirty power? If so how is that problem solved safely?

Thanks for any insight.

 

[amirm]

I'll repeat my question: if I am using balanced amp and dac with computer as the source, are there any weird ground loops, hums, noises that can manifest audibly from computer or dirty power? If so how is that problem solved safely?

Thanks for any insight.

Very unlikely.

 

[JSmith]

If so how is that problem solved safely?

Balanced, you'll be fine... unbalanced and with these issues, a ground loop isolator if a ground loop and a DC blocker if a DC bias on the AC.

This isolation transformer is sold in the Aus/NZ market;

https://www.tortech.com.au/product/isolation/isolation-transformer/

Earthing is NOT carried to Outlet Socket, hence Isolated and Floating

This is a proper isolation transformer too, as in ground is not passed through.

The standard configuration is advertised here as an audio product, specifically;

Audio AC Power Isolation Transformer 1000 VA

Audiophile DC blocker Isolation transformer allows an AC signal or power to be taken from one device and fed into another without electrically connecting the two circuits. Isolation transformers block transmission of DC signals from one circuit to the other, but allow AC signals to pass. They...

www.audiophile-store.com.au

This is a further clear example of how these are marketed at the audiophile.

In it's current configuration (without the "hack") the Trip-Lite is not a true isolation transformer. When working with an oscilloscope, I can understand using one of these, but seems overkill for an audible ground loop hum (which it won't rectify) or transformer buzz.


JSmith

 

[Geert]

In engineering vernacular it is a relay
No, it would trip, otherwise useless

An IMD is an Insulation Monitoring Device. It gives an alert on ground faults. It doesn't "trip" like a circuit braker. It's not meant to directly protect a person from being electrocuted, it only signals there's an insulation issue that needs to be looked at.

 

[amirm]

This isolation transformer is sold in the Aus/NZ market;

https://www.tortech.com.au/product/isolation/isolation-transformer/

I can't figure out what this is. Here is the schematic they show:

There is an EARTH terminal. Is it left disconnected? Or is it wired to other parts that are marked EARTH such as in the input cord?

 

[solderdude]

Left unconnected.

Safety ground is essential for ground referenced mains. When the live accidentally (due to a fault) touches the metal enclosure and there is no safety ground present you can get a nasty jolt/be killed.
When truly isolated (not balanced as truly balanced would have a CT connected to ground) both L and N are floating.
In this case when an internal fault connects Live (or Neutral) on the output side to the metal enclosure you don't get a jolt as no current can flow to the actual ground. So safety ground is not needed.

One could connect the safety ground but in that case, with some equipment, there are capacitors or MOVs or filter parts connected from L or N (or both) to ground. This creates a current path that may not be desirable for measurements but is safe to touch (as the metal enclosure cannot carry a voltage).

 

[JSmith]

Is it left disconnected? Or is it wired to other parts that are marked EARTH such as in the input cord?

It is disconnected on the output sockets, isolated and floating. The output plugs include a ground pin I believe for convenience of use so class 1 devices can be used with it, but is cosmetic only.

This RCD testing version appears different and closer to the Trip-Lite in relation to ground reference, but there is no schematic to confirm this @solderdude;

RCD Isolation Transformer - TorTech Pty Ltd

If you have problems when performing RCD testing, by tripping other RCD's upstream, then you need a Isolation Transformer. However a standard Isolation Transformer will not solve the Problem. A SPECIAL Isolation transformer unit is needed for RCD TESTING Purposes. By definition an Isolated...

www.tortech.com.au

As you suggested, the Trip-Lite is useless for rectifying a ground loop and isn't a true isolation transformer.


JSmith

 

[solderdude]

The tripplite can still be beneficial for DC blocking (are cheaper ways for it) and also 'mains leakage' issues can be lowered.
In some cases it thus might help to combat specific issues.
Not all ground loops pass through safety grounds. In those cases it could help.
These devices are not there to improve safety (which safety transformers are for) of audio equipment but to prevent direct connections to mains while leaving safety ground as is.
Not needed or double isolated gear anyway but safe when multiple devices are connected together (AV gear) where not all gear is connected via the isolation transformer so safety ground still acts as safety ground. (not audio ground, different thing)

Improving sound quality when there are no audible issues or power supply related issues is what Amir has shown in this test.
Not for possible scenarios where it could be a solution in certain cases to get rid of gremlins.

In the latter case it is not about improving sound quality but removing unwanted signals.

These specific conditions was not tested for nor was this the scope of Amirs test.
This test was about audio gear connected/used properly and to see if adding such a 'power conditioner' can improve audio coming out of connected gear.
Obviously this is not possible but many less technical minded folks want to see it 'put to the test'.
This doesn't mean it cannot offer an solution in specific cases where gremlins are reduced that might be or cause audible issues.

 

[pma]

For those who might be interested how a class II safety isolation transformer helps to cure an audible issue of ground loop (2 class I components, single ended link cables) in a common installation I have opened a thread with measurements of the isolation transformer effect:

Breve Tufvassons PFS 250 protective isolation transformer used against audio ground loop issue

Breve Tufvassons PFS 250 protective isolation transformer test – any good for audio? 1. Introduction There is a lot of misunderstanding on use of isolation transformers for audio. It should be noted that such device purpose is to get rid of possible or existing ground loop issues in audio...

www.audiosciencereview.com

 

[Lambda]

When truly isolated (not balanced as truly balanced would have a CT connected to ground) both L and N are floating.
In this case when an internal fault connects Live (or Neutral) on the output side to the metal enclosure you don't get a jolt as no current can flow to the actual ground. So safety ground is not needed.

I agree. but some here don’ŧ want to see this potential safety benefit of both L and N floating.

Even if there is no center tap the output would be "balanced" as in have the same impedance.
By truly balanced you mean "symmetrical" i assume? this can also be achieved by having symmetrical parasitic capacitance to ground.
Of cause it would not be perfectly symmetrical but dose not matter. in most caeses "current balanced) matters most.

The tripplite can still be beneficial for DC blocking (are cheaper ways for it) and also 'mains leakage' issues can be lowered.

The tripplite has also a very horrifying "benefit". It will stop your RCD from tripping.
Technical it is an isolation transformer just the "wong" side of it is isolated.

Beneficial for DC blocking, over voltage/current surge protection. some common mode filtering.
But of cause a "real isolation transformer" with floating output L and N would be better for most audio applications.

 

[DWI]

Amazon customer rating vs. ASR rating. just thought this is funny

I place a lot of faith in Amazon reviews. My wife was an Amazon Reseller and Amazon buyers (most of us) tend to be pretty genuine and unbiased, as a product can always be returned. My wife took Amazon criticism seriously and fed it into new product design.

Of course the difference here is that all the Amazon reviewers have used the product, whereas the likelihood is that hardly anyone on ASR has.

 

[Ingenieur]

An IMD is an Insulation Monitoring Device. It gives an alert on ground faults. It doesn't "trip" like a circuit braker. It's not meant to directly protect a person from being electrocuted, it only signals there's an insulation issue that needs to be looked at.

It can do both in this case.
It detects current leakage which could be thru a person.

We use it for dual purpose:
Leakage and ground fault.
We use it to trip a vacuum circuit breaker on 4160 VAC mining machines.
I apply protective relaying as part of my job.

Current can leak thru insulation deterioration/damage or a fault in it.
Or a damaged cable that is handled by a person.

The relay has contacts that can be used to 'trio' various devices to interrupt the fault/leakage.

 

[Ingenieur]

Not where i'm from... but clear communication don't seam to be your goal.
They call It IMD or in some other picture (your never mentions before) IMD relay. Never just relay beaus It would potentially confusing.


"It" refers to what?
https://en.wikipedia.org/wiki/It

it is confusing ;P
If you talk about the current "It"? the current must be bonded?
"current must be bonded. "does relay make no sense at all?
with no part for the current to flow there can't be current...



"It" again ?
"It means" or the current... i over t
or:

Or are we talking about the IT-System as in Isolé Terre
It is literately in the name Isolé. != bonding to Terre.


the touch voltage is not 0.
It is (the touch voltage) what ever Id*REA is (the current going trough Risiol times the grounding resistance)

So the lower Risol the lower Ut (toutch voltage) the lower toutch voltage, the lower "IT" (touch current)

Well, Bender is a German company.
Protective relaying is common everywhere.
Then again you are not an engineer.

I can't do anything about your lack of understanding.

No
Who's 'we'

if Ut > 0 current flows thru the person Rk.
So you were incorrect. The fault current is // divided inversely proportional to Risol and Rk.

The higher Risol the lower Ut.
Why? Because it limits the fault current.
If it were 0 current would be much higher similar the solidly bonded (vs impedance bonded) scenario.
More I = high Ut drop across Rk.

 

[Doodski]

We use it to trip a vacuum circuit breaker on 4169 VAC mining machines

Interesting. I was worked as a electrical assembler working with instrumentation, electrical-hydraulic and electronic-hydraulic systems on drilling rigs for water and petroleum too as well as wheel and track driven all terrain vehicles capable of up to 40 ton load driving in ~1 yard thick of mud. We'd take a set of bare flanges and build drilling rigs, trucks and even vehicles with tracks right there on the work place floor. Had ~70 welders working full time to keep up, the engineers and admin where on the floor above about 15m+ away at all times designing and doing stuff. I worked in other assembler positions for other categories of vehicles but that was the most interesting of them. So to get to the point now that you know I am interested. What kind of mining machines?

 

[Ingenieur]

Interesting. I was worked as a electrical assembler working with instrumentation, electrical-hydraulic and electronic-hydraulic systems on drilling rigs for water and petroleum too as well as wheel and track driven all terrain vehicles capable of up to 40 ton load driving in ~1 yard thick of mud. We'd take a set of bare flanges and build drilling rigs, trucks and even vehicles with tracks right there on the work place floor. Had ~70 welders working full time to keep up, the engineers and admin where on the floor above about 15m+ away at all times designing and doing stuff. I worked in other assembler positions for other categories of vehicles but that was the most interesting of them. So to get to the point now that you know I am interested. What kind of mining machines?

Hope I don't get gigged for an OT. Lol
But it's interesting.

Long wall and continuous.
The long wall systems are 1500-2000' long and have 7 motors totaling 12000 HP. Men walk under the shields. Huge.
We use CAT and Joy/Komatsu

 

[Doodski]

Hope I don't get gigged for an OT. Lol
But it's interesting.

Long wall and continuous.
The long wall systems are 1500-2000' long and have 7 motors totaling 12000 HP. Men walk under the shields. Huge.
We use CAT and Joy/Komatsu

Very impressive. I dig this sort of stuff. Very heavy duty awesome machine. I liked the video. Thanks.

 

[Ingenieur]

Very impressive. I dig this sort of stuff. Very heavy duty awesome machine. I liked the video. Thanks.

It's not all glamor, lol.
I work in low seam too. 36"
You have to crawl around, 3 miles in, 600' deep.

Stock image

But also mission critical operations
Underground data centers
Not stock photos
2 MW gensets x 6
UPS, SS transfer, floating dual conversion

 

[DonH56]

If people believe and try to convince others seeds can cure cancer, do you blame the people or do you blame the seeds?

I blame the one selling the seeds.

I'll repeat my question: if I am using balanced amp and dac with computer as the source, are there any weird ground loops, hums, noises that can manifest audibly from computer or dirty power? If so how is that problem solved safely?

Thanks for any insight.

A truly differential circuit, or a well-implemented balanced design, will isolate the signal path (+ and -) from the (earth, safety) ground path so as @amirm said it is highly unlikely. If there is such a loop, you can lift the ground (shield) on one end of your balanced cable (TRS or XLR) without affecting the signal and thus break the noise path.

I can't figure out what this is. Here is the schematic they show:

There is an EARTH terminal. Is it left disconnected? Or is it wired to other parts that are marked EARTH such as in the input cord?

I quoted Amir but agree with all the other responses... My one comment here is that floating only works if everything is floating, i.e. all other components are plugged into the isolation transformer. In this case, since there is no safety ground, there can be risk if anything in the circuit is connected to ground. An example would be having all your low-level components (e.g. AVP/preamp or computer) plugged into the isolation transformer, but a power amp or projector/TV that does have a safety ground connected to the AVP. Now the ground path is outside the transformer and relatively uncontrolled as far as the user is concerned. Shocking.

 

[Doodski]

It's not all glamor, lol.
I work in low seam too. 36"
You have to crawl around, 3 miles in, 600' deep.

Stock image
View attachment 199176

But also mission critical operations
Underground data centers
Not stock photos
2 MW gensets x 6
UPS, SS transfer, floating dual conversion
View attachment 199177
View attachment 199178

Nice installation of the gear. I'm seeing hydraulics in this place. Do they run some of it over spec? Like manufacturer spec it at say max 2200 PSI and run it at 3K PSI? With all the hydraulics operating in confined spaces it would be dangerous I think if a hose had a pinhole leak.

 

[PeteL]

Then again you are not an engineer.

I can't do anything about your lack of understanding.

I am not Lambda but this is quite condescending... Please let's be nice to each other. I am an engineer myself and I did not fully understood all you said neither. We all have our specific area of expertise and don't have experience on everything.