I have used the ART Dual Transformer/Isolator Hum Eliminator in several places with our church sound system. It eliminated most of the hum from our A/V systems audio board connection to the main sound board. As long as we have the gain on the main board a little low, we have no noticeable hum. It eliminated all the hum from our A/V systems PC sound connection to the A/V audio board board. This had been a big problem as the PC is connected to a projector that introduced a lot of inteference into the system. It also eliminated the hum from a long monitor speaker cable connection that required connecting two speaker cables together to reach the distance I had to cover. I used the Hum Eliminator to connect the cables. While it has not eliminated all the hum in every circumstance, it has been very effective in the cases listed above. The times it did not work effectively, we had to do some electrical work on the church lighting systems, which are over 20 years old, to get rid of the source of the interference.

This unit is very good item except for I had some trouble with clipping from different units that I plugged into it. I found by reading the specs that the clipping came from the 1/1 isolation transformers that are used. By adding some attenuation to the input signal the unit works well as I have recorded live concerts with this unit. I found another unit that works better. The Art Clean Box has done a better job except it does not have ground lift. I used a Ground loop isolator to get around this. This unit can also go the other way as well. Stereo to 2 XLR's and 2 XlR's to stereo line out.

I bought one of these for interfacing a balanced XLR output to the unbalanced line-ins on my soundcard... The unit worked good at first, eliminated ground loop niose and didn't add much coloration etc, but after a few weeks the ground loop hum emerged as well as horrible hiss and distortion/popping sounds that were NEVER present from the source to begin with. Shop elsewhere for an isolatino transformer.