Hi friends

For asking my questions, first there is a need to an intro.
I have an amplifier integrated (Musical Fidelity M6si) and I have a pair of Speakers (Focal Aria 948) my M6si has a USB input (24/96) for connecting to a computer. I did that. I bought a fine USB A to B cable for doing that, But as I know a good sound quality, it didn't interest me so much or not as I expected, for sound quality sake of course.
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In the other hand, I have an Audio interface (Steinberg UR 22 mkII) from before just for producing good sound quality. So I decide to use a standard RCA cabling with my amp, not the USB port anymore. My audio interface has a left and right TRS/TS jack (balanced/unbalanced) output. For using of an input of my amp and these jack outputs I must use a cable. A TRS/TS to RCA.
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Sorry for long intro. I have 3 questions. First of all, am I doing right as I mentioned above for cabling? For minimizing noise and poor quality as much as I can, which one is the best way: Using a TRS/TS to RCA cable (there is not too good cable in the market) OR buying a TRS/TS to RCA female ADAPTER, then I would buy a nice RCA to RCA standard cable and connect it to that adapter? And the last is, should I use TS or TRS jack for all this matter (Audio interface to Amplifier integrated)?
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You know, all of these is for improving sound quality matter.
Sorry for my English language, it's not my first tongue.

Best wishes...
Amir