JK Audio Pureformer - Stereo Isolation Transformer

Comments about JK Audio Pureformer Isolation Transformer:

I got this device to reduce the annoying computer whine I experienced when I connected my desktop computer to my earth-grounded stereo setup. I had the two connected with simple unbalanced cables, but since the signal ground in the computer's sound card was the same as the main power ground, there is a lot of high frequency hash from all the digital switching going on, and it rides on the connection as a common mode signal. This noise has a very low source impedance, so it cannot be helped by further grounding. Isolation transformers seemed the only solution.

The Pureformer did the job all right--the hash was at least 10 or 15 dB lower--but I started hearing really nasty distortion on music with even moderate levels of bass. Using a signal generator and an oscilloscope, I was able to see the problem: core saturation at low frequencies. At 20 Hz, the transformers could only handle a signal of about 140 mV before distorting. Naturally, at higher frequencies the threshold was higher, reaching 570 mV at 40 Hz and a decent 2.1 V at 100 Hz. The problem is that signals with this kind of bass are very easily encountered with normal music from consumer electronics.

Opening up the metal box revealed two dinky little transformers. Truly adequate performance would require quite a bit more metal in the transformer cores. No wonder the manufacturer doesn't provide much in the way of specs!

I tamed the problem by reducing levels 10 dB, but that's not an ideal solution. At some point I'm going to have to get a couple of better transformers.

I am checking "recommended" with the caveat that you keep signal levels very low.

Comments about JK Audio Pureformer Isolation Transformer:

I am using this box between a mixer's tape out and a laptop's line in. Previously, the noise level was out of hand, and now it is tamed. We're still getting some noise, but I'm fairly sure it's from other components.

Comments about JK Audio Pureformer Isolation Transformer:

I have a high-end audio system that somehow developed a ground loop. I initially tried a cheaper device from another retailer and manufacturer that also eliminated the ground loop, but I noticed a marked reduction in sound quality. With over $10k invested in my components, this was not acceptable. I researched this item and noticed its negligible insertion loss and performance over the audio spectrum. I will eventually try to solve the ground loop issue at its root, but with the Pureformer's outstanding performance I don't need to rush! If you spend more for another device it's simply because you want to, not because you have to!

Comments about JK Audio Pureformer Isolation Transformer:

Works Beautiful!!! Had a Hafler P7000 350w/Ch Amp with ground loop noise issues. Tried Radio Shack equivalent which worked but had low end roll-off and was using Amp as a Sub Amp so that was no good. Put this in line ground loop GONE and Silence had returned with no degradation in Audio Freq 20hz-20Khz Nice!!! Well worth it if you need the BEST and the complete audio spectrum for your equipment.

Comments about JK Audio Pureformer Isolation Transformer:

I use this ground loop isolator to remove the hum when connecting a laptop's headphone output to my stereo amplifier.
Build quality seems good, and I have noticed no loss of signal intensity and no distortion.
I used a $10 isolation transformer before, but that had poor-quality connectors plus distortion.

Comments about JK Audio Pureformer Isolation Transformer:

I had a bad hum when I connected my computer soundcard to my home stereo. This took it right out. Nice solid construction too.

Comments about JK Audio Pureformer Isolation Transformer:

It's so easy to install...take it out of the package and connect it. Does the job!

Comments about JK Audio Pureformer Isolation Transformer:

Solves the digital noise issues between my computer's sound card and my audio interface without degrading frequency response.

Comments about JK Audio Pureformer Isolation Transformer:

For those of you that use your laptop for demonstrations, in my case, specifically audio, you never know what you will get as far as noise added.
Even apple laptops generate trash via audio out when hooked up to external systems. Being an audio engineer I needed a reliable transformer to isolate these issues and the JK Pureformer was inexpensive and does the trick. Adding 3.5mm jacks in parallel would be even better but for the price and a couple of decent cables it does the job. Problem is, everyone one wants to borrow this. I tell them to get there own. I can now turn things up and not hear that annoying laptop trash buzzing in the house.

Comments about JK Audio Pureformer Isolation Transformer:

I'm using this product between my laptop and a sound board to filter out the audio noise coming from my laptop's line out port. It is a simple install and does what it says it will.

Comments about JK Audio Pureformer Isolation Transformer:

I got this device to reduce the annoying computer whine I experienced when I connected my desktop computer to my earth-grounded stereo setup. I had the two connected with simple unbalanced cables, but since the signal ground in the computer's sound card was the same as the main power ground, there is a lot of high frequency hash from all the digital switching going on, and it rides on the connection as a common mode signal. This noise has a very low source impedance, so it cannot be helped by further grounding. Isolation transformers seemed the only solution.

The Pureformer did the job all right--the hash was at least 10 or 15 dB lower--but I started hearing really nasty distortion on music with even moderate levels of bass. Using a signal generator and an oscilloscope, I was able to see the problem: core saturation at low frequencies. At 20 Hz, the transformers could only handle a signal of about 140 mV before distorting. Naturally, at higher frequencies the threshold was higher, reaching 570 mV at 40 Hz and a decent 2.1 V at 100 Hz. The problem is that signals with this kind of bass are very easily encountered with normal music from consumer electronics.

Opening up the metal box revealed two dinky little transformers. Truly adequate performance would require quite a bit more metal in the transformer cores. No wonder the manufacturer doesn't provide much in the way of specs!

I tamed the problem by reducing levels 10 dB, but that's not an ideal solution. At some point I'm going to have to get a couple of better transformers.

I am checking "recommended" with the caveat that you keep signal levels very low.

Comments about JK Audio Pureformer Isolation Transformer:

I am using this box between a mixer's tape out and a laptop's line in. Previously, the noise level was out of hand, and now it is tamed. We're still getting some noise, but I'm fairly sure it's from other components.

Comments about JK Audio Pureformer Isolation Transformer:

I have a high-end audio system that somehow developed a ground loop. I initially tried a cheaper device from another retailer and manufacturer that also eliminated the ground loop, but I noticed a marked reduction in sound quality. With over $10k invested in my components, this was not acceptable. I researched this item and noticed its negligible insertion loss and performance over the audio spectrum. I will eventually try to solve the ground loop issue at its root, but with the Pureformer's outstanding performance I don't need to rush! If you spend more for another device it's simply because you want to, not because you have to!

Comments about JK Audio Pureformer Isolation Transformer:

Works Beautiful!!! Had a Hafler P7000 350w/Ch Amp with ground loop noise issues. Tried Radio Shack equivalent which worked but had low end roll-off and was using Amp as a Sub Amp so that was no good. Put this in line ground loop GONE and Silence had returned with no degradation in Audio Freq 20hz-20Khz Nice!!! Well worth it if you need the BEST and the complete audio spectrum for your equipment.

Comments about JK Audio Pureformer Isolation Transformer:

I use this ground loop isolator to remove the hum when connecting a laptop's headphone output to my stereo amplifier.
Build quality seems good, and I have noticed no loss of signal intensity and no distortion.
I used a $10 isolation transformer before, but that had poor-quality connectors plus distortion.

Comments about JK Audio Pureformer Isolation Transformer:

I had a bad hum when I connected my computer soundcard to my home stereo. This took it right out. Nice solid construction too.

Comments about JK Audio Pureformer Isolation Transformer:

It's so easy to install...take it out of the package and connect it. Does the job!

Comments about JK Audio Pureformer Isolation Transformer:

Solves the digital noise issues between my computer's sound card and my audio interface without degrading frequency response.

Comments about JK Audio Pureformer Isolation Transformer:

For those of you that use your laptop for demonstrations, in my case, specifically audio, you never know what you will get as far as noise added.
Even apple laptops generate trash via audio out when hooked up to external systems. Being an audio engineer I needed a reliable transformer to isolate these issues and the JK Pureformer was inexpensive and does the trick. Adding 3.5mm jacks in parallel would be even better but for the price and a couple of decent cables it does the job. Problem is, everyone one wants to borrow this. I tell them to get there own. I can now turn things up and not hear that annoying laptop trash buzzing in the house.

Comments about JK Audio Pureformer Isolation Transformer:

I'm using this product between my laptop and a sound board to filter out the audio noise coming from my laptop's line out port. It is a simple install and does what it says it will.