This is a review and detailed measurements of the Jensen ISO-MAX IP-XX balanced isolation transformer. It is on kind loan from a member and costs US $220.
While the enclosure is small, it is quite heavy for its size and feels solid as a rock. The weight likely comes from the transformer which passively provides isolation between input and outputs. Standard balanced inputs should provide fair amount of that already but this steps that up in case you are still getting hum and buzz. Here are the company bullet points:
Jensen ISO-MAX PI-XX Measurements
I treat the box as if it were a preamp and ran our standard dashboard:
There is a small insertion loss, causing 0.1 volt minimal reduction in output voltage at the impedance used for testing (40/200K ohm). Third order harmonic is responsible for some 15 dB reduction from what the analyzer is capable of. But this is not the full story as they say. Distortion in transformers gets worse as frequencies go down. And also increase with voltage. Let's examine these effects:
We see a pretty dramatic increase in distortion when sweeping backwards from 20 kHz. It is reasonable down to about 500 Hz below which, you start to compromise 16 bit fidelity. Lowering the voltage to 2 volts help but not much more below that. We can see this better in family of frequency and voltage sweeps:
So best to stay below 2 volts. As transformers go though, these are pretty good distortion numbers.
There is naturally phase error proportional with frequency:
Main claim to fame is isolation and we can test that with CMRR:
These are very good numbers.
EDIT: Forgot the frequency response:
Conclusions
If you have ground loops/mains leakage, any solution will mean Christmas coming early!
Lots of solutions out there but many add noise and distortion. The Jensen PI-XX being transformer based, doesn't impact noise but does add distortion. It is a high quality transformer though and tolerates fair bit of input voltage before getting unhappy at lower frequencies. Ultimately though, you don't want to use it if you don't have to.
I am going to recommend the Jensen ISO-MAX PI-XX isolation transformer.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
While the enclosure is small, it is quite heavy for its size and feels solid as a rock. The weight likely comes from the transformer which passively provides isolation between input and outputs. Standard balanced inputs should provide fair amount of that already but this steps that up in case you are still getting hum and buzz. Here are the company bullet points:
- Eliminates hum and buzz caused by ground loops
- Delivers exceptionally low distortion down to 20 Hz
- Ruler flat frequency response from 5 Hz to 40 kHz
- Plug and play easy to use, no power required
Jensen ISO-MAX PI-XX Measurements
I treat the box as if it were a preamp and ran our standard dashboard:
There is a small insertion loss, causing 0.1 volt minimal reduction in output voltage at the impedance used for testing (40/200K ohm). Third order harmonic is responsible for some 15 dB reduction from what the analyzer is capable of. But this is not the full story as they say. Distortion in transformers gets worse as frequencies go down. And also increase with voltage. Let's examine these effects:
We see a pretty dramatic increase in distortion when sweeping backwards from 20 kHz. It is reasonable down to about 500 Hz below which, you start to compromise 16 bit fidelity. Lowering the voltage to 2 volts help but not much more below that. We can see this better in family of frequency and voltage sweeps:
So best to stay below 2 volts. As transformers go though, these are pretty good distortion numbers.
There is naturally phase error proportional with frequency:
Main claim to fame is isolation and we can test that with CMRR:
These are very good numbers.
EDIT: Forgot the frequency response:
Conclusions
If you have ground loops/mains leakage, any solution will mean Christmas coming early!
Lots of solutions out there but many add noise and distortion. The Jensen PI-XX being transformer based, doesn't impact noise but does add distortion. It is a high quality transformer though and tolerates fair bit of input voltage before getting unhappy at lower frequencies. Ultimately though, you don't want to use it if you don't have to.I am going to recommend the Jensen ISO-MAX PI-XX isolation transformer.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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