A couple months ago I inserted the GroundMaster CITY into my main system and would like to share my thoughts. I have a PSM156 so this was an inexpensive and easy upgrade. I wasn’t expecting much but boy was I surprised! It’s very easy to test - just unplug the cable from the port on the PSM156 and listen. What I (and my wife who could care less about it) noticed, was an immediate bump in clarity. The music got slightly louder with increased clarity, tighter bass and better space. At $250 this is probably the best bang for the dollar upgrade I have ever made. Considering I have a dedicated circuit, quality PCs and a PSM156, it was hard to believe that there was still that much noise on my lines.
I was so impressed I immediately ordered the GroundMaster CITY and RouteMaster to ground my signal-based components. I plugged the RouteMaster cables into my DAC, pre and amp. The result? Nothing. I could not hear any discernible difference. I tried the RouteMaster with and without the PSM156 connected to the GroundMaster CITY. There may have been a very slight uptick in SQ when the PSM156 was disconnected from the GroundMaster CITY but it wasn’t consistent.
Maybe I need a more resolving system for the GroundMaster CITY/RouteMaster combo to make a difference? Or maybe draining the noise from the mains filter takes care of 95% of the problem? There probably isn’t a lot of noise being generated by quality electronics downstream of the mains filter. However, if you don’t have a PSM156 with a convenient port to ground the chassis, maybe the GroundMaster CITY/RouteMaster combo is the next best thing?
I currently have the GroundMaster CITY/RouteMaster combo on my second system but it does not have enough resolution to show a difference. I will probably be selling the GroundMaster CITY/RouteMaster combo but will keep the GroundMaster CITY connected to my PSM156 forever. As a matter of fact if I were to order a PSM156/136 in the future I would just add the GroundMaster CITY to the order up front.