Your version is probably good actually and maybe the best one. This is what is says on the Jensen isolator page I found about your model: The 1:1 ratio output type transformer inside has the least passive losses of the three types, and will eliminate 60 Hz ground loop noise. However, since the output transformer does not have an internal Faraday shield like the PI-2XX and PB-2XX, higher frequency "buzz' noises will pass through, making the PO-2XX the least effective of the three for eliminating noise problems. The PO-2XX can be used at either end of a long cable run, but is best used at the start of the run. (Formerly DM2-2XX) So seems like Faraday shield may not be on the PO version, but maybe the PI version is not as transparent.