Does anyone notice a reduction in sound quality when a tuner is part of ther audio chain?

Yes for sure better gear will help. RCA connections share ground. XLR is a better option.

Glad to see you don’t buy into the idea that your gear is so resolving that simply the proximity of the tuner will affect it. There are many tin toilers here who believe that detrimental effects on the music from extraneous factors like cables etc. indicates their gear is highly resolving (instead of realizing that something is faulty with the setup).

Not an expert, but I think that the IF amplifiers in tuners can be pretty noisy and emit a lot of noise. If you leave them on all the time then this would explain it.

This is kind of how radar detectors detectors work, they pick up on the IF amplifier output.

Best,

E

This happens all the time. The cause is usually noise from a digital source contaminating the rest of your system. I don't know what kind of tuner you have, but you're options are to get a higher quality tuner, a PC like the JPS Digital AC, or a power conditioner that isolates the outlets from each other.

If you call Cable Company and explain your problem, they'll know what to send you (demos that you can try first to make sure a product fixes the problem).

It also depends on the preamp. Some tuners can bleed into the unbalanced inputs if the tuner has a high gain.

Mitchb 4-14-2017
... 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?

I'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.

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