Mitchb 4-14-2017I'm not sure that unplugging the interconnects from the preamp will help, although it might. I see in your system description that your MD-106T tuner is located immediately below your Pass X-1 preamp, and it therefore seems very conceivable to me that the tuner may be radiating RFI into the preamp's circuitry through the air.
... my tuner is out being repaired which is how I notice the difference in sound. I think it's a matter of RF which is leaking from tuner input into the rest of the preamp. I think it's not resolvable unless I actually unplug the tuner's interconnects from the preamp.I would leave the tuner plugged into ac when not in use but left off and unplugged from preamp. I'm hoping this would be my solution. Any thoughts or advice?
When you get the tuner back it may be informative to plug it into the AC and bring a portable battery powered AM radio close to it, with the radio tuned to an unused frequency and its volume control set to a position you would normally use. If you hear a lot of noise from the radio when it is brought close to the tuner and/or close to the connectors on its rear panel, even when the tuner is turned off, it would say that the key to a solution may be to relocate the tuner.
Good luck. Regards,
-- Al