This is more of a first impression rather that a formal review. The results so far have been too dramatic not share. This weekend I received the "Hot Box" made by Chris VenHaus. I had ordered it with the auricap option to aid in my undeclared war on RFI/EMI power line contamination. The unit itself looks very DIY, a standard metal utility box with two outlets attached to a short and thick power cord. I immediately opened it to get an idea of the wiring scheme. Inside was very close quarters and I didn't want to disturb things. However I did notice that the 4 auricaps were wired paralell, two to each outlet. I plugged it in to the amp side of my system right before a high current Ultimate Outlet. The amp is plugged into the Ultimate Outlet.
The first song I listened to was "Call Mr. Lee" by Television. This is not one of my "reference" songs. I had just rediscovered it after a long time and my wife and I had just remarked how good it sounded when we played it the day before. The first adjective that came to mind when listening was "holographic". Sound stage much deeper and wider. My speakers are VMPS RM2's. Great speakers, but like alot of large wide speakers don't particulary "image" well. Hearing what they could do with this song was a revelation. The midrange and upper sounded alot clearer. Tom Verlaines guitar never sounded as real to me.
My next CD was a "reference", "Guitar Passion" by Charo. Her spanish guitar is great test of the midrange. My wife and I both heard more detail. For lack of a better discription every just sounded clearer.
My third reference song was "Time Has Come Today" by the Chambers Brother. This song is a good test of guitar bass and the "tick tocks" also show off stereo imaging. I also like to play it loud to annoy my wife! Anyway the effect of the Hot Box can be heard here also. The bass seem slightly recessed from before. This may be because the Hot Box has not broken in yet. It was not a big difference, but noticeable. The main difference is an improvement in the midrange detail. I heard grunts from the singer I didn't even know were there before!
In short this is one of the more dramatic tweaks I have done. The Ultimate Outlet did improve things. I have also shielded my amp and digital components against RFI. All my components have expensive aftermarket power cords. I use quietline filters on my other outlets. All of these things have noticeably improved the sound. I didn't think that there was much room for improvement but I was wrong. I don't know how much of this is system dependent, but I would recommend looking into the Hot Box with the Auricap option for power line conditioning.