Hi all. I have the SP-14 preamp custom built by Roy himself with all the best parts. It has the Mundorf caps on one output channel and the KY's on the other. I have a multi amp set up that includes the VTA-120 power amp. I have a noticeable audible buzz from the speakers on all amps except the VTA-120. I'm thinking it's about at 120hz or so as it's not a 60hz hum. I have changed cables, outlets for the power source etc..., re-routed audio cables to no avail. I have hooked this amp to a Sony ES55 power amp, a Transcendent Sound OTL tube amp, a Harmon Kardon and a Heathkit power amp with the same results with all. I have even taken everything to a different room but the results are still the same. A low level (more a buzz than a hum) that is clearly noticeable. My speakers are Klipsh with an spl of around 95db but in the other room using some speakers in the 85db range the buzz is still present. Roy supplies Tung-Sol 6SN7's which are fine but I have changed them out for some vintage Sylvania 6SN7's from the 50's (clearly Superior). The noise level is the same regardless of which tubes I use. What puzzles me is why the VTA-120 has no noise at all but all other amps do. I wouldn't think the SP-14 is designed to be "perfectly" matched to the VTA-120 amp and nothing else. Could it possibly be the rectifier tube that's causing the issue? I'm using the supplied one provided by Roy. Anyone with a possible solution would be of great help.