• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Tripp Lite IS250 Review (Isolation Transformer)

Rate this product:

  • 1. Waste of money for audio use

    Votes: 121 71.2%
  • 2. Not terrible (postman panther)

    Votes: 12 7.1%
  • 3. Fine (happy panther)

    Votes: 27 15.9%
  • 4. Great (golfing panther)

    Votes: 10 5.9%

  • Total voters
    170

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
Do you realize the N and G are bonded?
This is common practice in industry,, impedance grounding of sorts.
The value of Risol is 24xRk, 120 kOhm
DAAD923E-BDE8-4D28-8122-DB4A131575F7.jpeg
 

PeteL

Major Contributor
Joined
Jun 1, 2020
Messages
3,303
Likes
3,838
I would agree replacing it would be better but you seam to know audiophiles better then me... How would they react if you tell them to just replace there >1000$ turntable and tube amp with an 200$ chine dac :D
The way electrical issues works, most of the time, not all the time, each devices on their own are fine, that's when you put them in a system that ground loops or other problems arise. There is just not one single "right" way to do things. There is no such thing as, device X is immune to electrical issues. It depend what there is connected to it.
 

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,785
Likes
1,519
I don’t know what your trying to say.
Do you realize the N and G are bonded?
I don’t see "N" nor do i see G in this picture... i assume your referring to PE and L2 in this picture?
What do you men by "bonded"?

Bonded means to me held on the same potential.

but they are not.
They are only loosely referenced via unavoidable parasitic transformer to ground(PE) captive coupling (CL-L1)
and parasitic transformer isolation resistance to ground (PE) (Risol L-L1)

This is common practice in industry,, impedance grounding of sorts.
This is unavoidable do to physics there is always some parasitic capacitance and leakage.
What do you mean by "impedance grounding of sorts." Grounding always has an impedance.

The value of Risol is 24xRk, 120 kOhm
How do you know? why? where is ths number coming from?
Risol can be Mega or Giga ohms.
 

DWI

Senior Member
Joined
Feb 19, 2021
Messages
495
Likes
437
I am arriving at the conclusion that these people absolutely believe in benefit of such devices despite all the evidence I have produced. They use them themselves and are defending them as such. It shows how strong the assumptions are around this category product that even our core members believe in them. And worse yet, are unwilling to change their mind despite large volume of data presented to them
Just spent 5 minutes (thankfully not a waste of my life as watching some sport on the TV) looking at the Amazon reviews and basically this product is an economic solution for hum and buzz on mostly mid-fi AV and guitar amps, amongst many other applications, and often it is being used to isolate devices from each other. The irony is that a high-end audio IS250 happy customer got rid of a hum using the IS250 to isolate his CD player and pre-amp, and plugged his tube amplifier into the wall.

If this cheap product can eliminate hum or buzz, or other power issues, which it clearly did for most but not all buyers, then if the the measurements say it's useless, they aren't telling the whole story. I think you are deluding yourself that people here are suffering from owner bias.
The way electrical issues works, most of the time, not all the time, each devices on their own are fine, that's when you put them in a system that ground loops or other problems arise. There is just not one single "right" way to do things. There is no such thing as, device X is immune to electrical issues. It depend what there is connected to it.
Quite right, the problem with testing "this category product" in isolation is that their merit is primarily as part of a system.

Screenshot 2022-04-10 at 20.22.18.png


Screenshot 2022-04-10 at 20.17.25.png
 

Attachments

  • Screenshot 2022-04-10 at 20.15.11.png
    Screenshot 2022-04-10 at 20.15.11.png
    233.5 KB · Views: 48
  • Screenshot 2022-04-10 at 20.15.52.png
    Screenshot 2022-04-10 at 20.15.52.png
    378.9 KB · Views: 49
  • Screenshot 2022-04-10 at 20.18.17.png
    Screenshot 2022-04-10 at 20.18.17.png
    463.3 KB · Views: 51
  • Screenshot 2022-04-10 at 20.19.37.png
    Screenshot 2022-04-10 at 20.19.37.png
    511.1 KB · Views: 47
  • Screenshot 2022-04-10 at 20.22.05.png
    Screenshot 2022-04-10 at 20.22.05.png
    104 KB · Views: 46

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
I don’t know what your trying to say.

I don’t see "N" nor do i see G in this picture... i assume your referring to PE and L2 in this picture?
What do you men by "bonded"?

Bonded means to me held on the same potential.

but they are not.
They are only loosely referenced via unavoidable parasitic transformer to ground(PE) captive coupling (CL-L1)
and parasitic transformer isolation resistance to ground (PE) (Risol L-L1)


This is unavoidable do to physics there is always some parasitic capacitance and leakage.
What do you mean by "impedance grounding of sorts." Grounding always has an impedance.


How do you know? why? where is ths number coming from?
Risol can be Mega or Giga ohms.
They are bonded thru an impedance.
Otherwise a fault in the secondary would not trip.
 
Last edited:

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,785
Likes
1,519
If this cheap product can eliminate hum or buzz, or other power issues, which it clearly did for most but not all buyers, then if the the measurements say it's useless, they aren't telling the whole story. I think you are deluding yourself that people here are suffering from owner bias.
Maybe some making the improvements they claim to hear up. but only 9% "bad" reviews is telling surely it must do something right.

But on the other hand... maybe you can’t trust Amazon reviews.
1649625992080.png



If this cheap product can eliminate hum or buzz, or other power issues, which it clearly did for most but not all buyers, then if the the measurements say it's useless, they aren't telling the whole story.
It sure did help for some

The thing is a million measurements that show it dose nothing don’t proof it can’t do nothing
But one single test showing it’s working proves it can work.


They are bonded thru an impedance.
They? common put some effort in your explanation your talking about L2 and PE?
Then everything in the universe is bonded to everything trough an impedance... some are just very high.

The question here is if the impedance is high or low.
How do you made up this 120kOhm number?
 

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
Maybe some making the improvements they claim to hear up. but only 9% "bad" reviews is telling surely it must do something right.

But on the other hand... maybe you can’t trust Amazon reviews.
View attachment 199033



It sure did help for some

The thing is a million measurements that show it dose nothing don’t proof it can’t do nothing
But one single test showing it’s working proves it can work.



They? common put some effort in your explanation your talking about L2 and PE?
Then everything in the universe is bonded to everything trough an impedance... some are just very high.

The question here is if the impedance is high or low.
How do you made up this 120kOhm number?
Stop with the insults.
The R is part of the kit

You tell me how you derive the 120 k
You're the expert.

It's only 115 k

This is effortless for me

And Bender (they) used the wrong body R. International standards are 600 - 2000 Ohm depending on conditions.
Perhaps he has EH rated shoes and gloves. But then 120 would not shock him, he would not conduct.

Often the R is internal to the relay.
Note the relay is connected to L, N and G
 
Last edited:

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,785
Likes
1,519
The R is part of the kit
What "R" what kit? Pleases you need to be more precises...
Your Talking about "Risol" like "isolation" so the inherent isolation resistance from the transformer?
But what "kit" the transformer is not including any "kit"

You tell me how you derive the 120 k
i did not i just quoted your post and asked how you came up with this number.

This is effortless for me
cool.

And Bender (they) used the wrong body R. International standards are 600 - 2000 Ohm depending on conditions.
Perhaps he has EH rated shoes and gloves. But then 120 would not shock him, he would not conduct.
Cool you shuld Email them. i’m sure they are happy to her from you.

I don’t actually see them use a fixed but value for boy resistance "Rk" in the picture you posted... but maybe your looking at an other picture without telling us?
 

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
We prefer to trip before the person is shocked. Not while being shocked.

Even if simultaneous:
120 V
Circuit protection 10 A
Body R 1000
EGC/N (sec of xfmr) 0.5 Ohm (very short run)
1 // 1000 ~ 0.5 Ohm
The device should have a CB or fue

Fault I = 120 / 0.5 = 240 A
EGC I = 1000/(1000 + 1 x 240 = 239.88 A
I body ~ 120 mA (120 V / 1000 Ohm) or
0.5/1000.5 x 240 = 120 mA
CB 120/20 ~ 1200% trip time <0.5 sec
time = (150 lb/120 mA)^2 ~ 1.56 sec
Trips well before fibrillation
In the nearly impossible event of simultaneous fault/touch.
 

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
What "R" what kit? Pleases you need to be more precises...
Your Talking about "Risol" like "isolation" so the inherent isolation resistance from the transformer?
But what "kit" the transformer is not including any "kit"


i did not i just quoted your post and asked how you came up with this number.


cool.


Cool you shuld Email them. i’m sure they are happy to her from you.

I don’t actually see them use a fixed but value for boy resistance "Rk" in the picture you posted... but maybe your looking at an other picture without telling us?
The Bender product you posted.
YOU posted without knowing what it is. Lol

That is not the xfmr insulation.
That is not the conductor insulation
That is not capacitive coupling
Those > 10 -20 MOhm, only 8-10 uA would flow. They trip < 1 mA or 1000 uA.

How would you determine it?
It is very simple, and is not xx MOhm range.

You can determine ~ Rk from the picture.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,393
Location
Seattle Area
From an Engendering side i would say test it on an device that has problems wit Mains leaks and has high amplification / Lowe level input signals. like a phonon preamp.
Phono preamps are not a reliable device to use for this as they are already so variable just sitting there.
 

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
What "R" what kit? Pleases you need to be more precises...
Your Talking about "Risol" like "isolation" so the inherent isolation resistance from the transformer?
But what "kit" the transformer is not including any "kit"


i did not i just quoted your post and asked how you came up with this number.


cool.


Cool you shuld Email them. i’m sure they are happy to her from you.

I don’t actually see them use a fixed but value for boy resistance "Rk" in the picture you posted... but maybe your looking at an other picture without telling us?
The fault I is divided between the person Rk and Risol.
What if Risol was not there?
What if the relay ground was lifted?
What does Id>> mean?
Why is the enclosure bonded?

Does the relay measure V across Risol?
If not, what does it measure?

So in a controlled allowed use, with qualified personnel maintaining the gear, and the protective relaying you could eliminate the solid bond.
The Code allows that.
But bonding is safer, more reliable and less costly.

Those relays are $$$ vs. a 6" piece of wire for a 1/1000000 chance of a simultaneous fault/shock. And the bonding provides similar protection < threshold of fibrillation.
 
Last edited:

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,785
Likes
1,519
We prefer to trip before the person is shocked. Not while being shocked.
"We" and as opposed to whom? and how would you do it before. sounds like you need a time machine.
Or you define a "save" current that don’t count as shock.

The fault I is divided between the person Rk and Risol.
What if Risol was not there?
What if the relay ground was lifted?
What does Id>> mean?
lol nop.
you can say current an resistance btw.
But no fault current is Not divided between the person (Rk) and the isolation (Risol) resistance.
they are in Series! current I will not divide if in series...
Maybe you shuld go back to the basic and look at kirchosf current law.

What if Risol was not there?
You mean infinite. then no current would flow... so now shock
 

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
"We" and as opposed to whom? and how would you do it before. sounds like you need a time machine.
Or you define a "save" current that don’t count as shock.


lol nop.
you can say current an resistance btw.
But no fault current is Not divided between the person (Rk) and the isolation (Risol) resistance.
they are in Series! current I will not divide if in series...
Maybe you shuld go back to the basic and look at kirchosf current law.


You mean infinite. then no current would flow... so now shock
Nice deflection. But no answers. Lol
You know what V and I and R, represent?
btw, I can't 'say', I'm not speaking, I'm writing.

What if Risol was not there?
What if the relay ground was lifted?
What does Id>> mean?
Why is the enclosure bonded?

Does the relay measure V across Risol?
If not, what does it measure?
One more, what does IMD mean?

Really? Not divided or in //? Lol
How would 5 V be impressed across the body Rk with NO I? Where does it come from if not L1? Magic current!?

My grammar usage will get better once you engineering does. I'm not holding my breath. Lol

95D568BB-1CFC-4C1B-93FC-384D1C77376E.jpeg
 

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,785
Likes
1,519
What if Risol was not there?
No current would flow.

What if the relay ground was lifted?
there is no "relay" i’m sure your referring to the IMD "isolation monitoring device"
it would potbelly detect if it ground would be lifted... but this depends on specifics not in this simplified schematic ant also not relevant for this discussion.

Why is the enclosure bonded?
so it can be detect if L1 or L2 are making contact to the enclosure
and as an safety measure to keep its potential low.

What does Id>> mean?
the majority of the drain current


Really? Not divided or in //? Lol
How would 5 V be impressed across the body Rk with NO I?

No one claims ther is 5V? don’t you know what " < " means?

current.png


Green is the current going trough the person as you can see
Rk Rst Rae1 Rae Risol are in series
so no "division"
if Risol is infinite no current will flow trough Rk
 

Ingenieur

Addicted to Fun and Learning
Joined
Apr 23, 2021
Messages
938
Likes
747
Location
PA
No current would flow.


there is no "relay" i’m sure your referring to the IMD "isolation monitoring device"
it would potbelly detect if it ground would be lifted... but this depends on specifics not in this simplified schematic ant also not relevant for this discussion.


so it can be detect if L1 or L2 are making contact to the enclosure
and as an safety measure to keep its potential low.


the majority of the drain current




No one claims ther is 5V? don’t you know what " < " means?

View attachment 199068

Green is the current going trough the person as you can see
Rk Rst Rae1 Rae Risol are in series
so no "division"
if Risol is infinite no current will flow trough Rk
Wrong

In engineering vernacular it is a relay
No, it would trip, otherwise useless
From a Bender catalog.
E5463D17-65C6-49C0-A16B-98A855AEA721.jpeg


Wrong
It must be bonded to trip upon a ground fault or the person is the only path

Wrong
It means the value of Id (based on Risol) must be much greater the capacitive coupling current. Why? Keep reading

Ut ~< 5 V, 1 mA max = It, thru Rk/person.
"t" subscript is touch.
Less than, not 0, or they would say
Ut = 0
It's based on what Risol is selected to allow the relay setpoint >> capacitive coupling current to avoid nuisance tripping.

It is in //
All fault Id and It is supplied by L1
No magic I
 
Last edited:

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,785
Likes
1,519
In engineering vernacular it is a relay
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 must be bonded to trip upon a ground fault or the person is the only path
"It" refers to what?
https://en.wikipedia.org/wiki/It
images

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 means the value of Id (based on Risol) must be much greater the capacitive coupling current. Why? Keep reading
"It" again ?
"It means" or the current... i over t
or:
images

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

Ut ~< 5 V, 1 mA max = It, thru Rk/person.
"t" subscript is touch.
Less than, not 0, or they would say
Ut = 0
It's based on what Risol is selected to allow the relay setpoint >> capacitive coupling current to avoid nuisance tripping.
the touch voltage is not 0.
It is :D(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)
 
Last edited:

rebbiputzmaker

Major Contributor
Joined
Jan 28, 2018
Messages
1,099
Likes
463
I am arriving at the conclusion that these people absolutely believe in benefit of such devices despite all the evidence I have produced. They use them themselves and are defending them as such. It shows how strong the assumptions are around this category product that even our core members believe in them. And worse yet, are unwilling to change their mind despite large volume of data presented to them.
What you’re saying is very true and quite reasonable but what might be a problem for some people is that when this becomes projected on the mainstream consumer device which is not possibly the culprit here.

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

Of course when somebody sells some overpriced audiophile power device or cable or some other foolishness they deserve bring outed. But some less informed readers also project the same ire onto the simple mainstream manufacturer who is not part of the scam really. Is that possibly a way to look at this and which might make more sense and may be an easier way to understand what’s going on??? And… maybe the products in questions should be categorized differently and discussed as if they are really not overpriced audio foolery. You are not doing this intentionally but judging by some of the comments here the readership tends to do that even though that’s not really your intention so maybe some clarity of this can be mentioned in the reviews for the less informed.
 
Top Bottom