I recently purchase one and the improvements is oblvious if you have dirty lines,if you have clean lines I doubt you will hear any results,its not a dramatic impact but subtle "elimination" of surface top riding RFI.I had a slight problem with a low noise hum during the day,its still there but I noticed a more rounded presentation,cymbals has slightly more extension.I plug my right into my conditioner which seems to offer the most improvement,I tried a downstream recepticle and the improvements barely was noticable.Would two help?..probably not if you have dedicated treated lines,but if you need a device that will strip another film of dirt from the house lines I recommend this product,considering tweaks are a hit and miss in the audio world I condsider the Blue Circle BC 86 III as bargain.IMHO any improvement of a home audio setup starts at the source,like they say " garbage in,garbage out".