Ok, so I just bought a Steinberg UR242 to use in combination with my Shure KSM44A microphone. Is it viable to connect a high end preamp to it and how much would it affect the recording quality. Would it improve a lot or should I buy an other interface?
Check the diagram in the manual. The 3-4 inputs on the UR 242 appear to be balanced inputs that bypass the built-in mic pres. It looks like you can still insert the built-in fx if you want. Should be pretty clean signal path.
I would ask that you define what ‘high end preamp’ means to you? Are you looking for character, super clarity, or just hoping that a more expensive preamp will solve problems?
Trust that I am not talking down but asking questions I wish I had been asked early on in my learning recording.
The preamps in your interface are quite clean and have decent gain. I would suggest looking into room, mics, and recording techniques before throwing money at a high end preamp.
But yes, you can connect another preamp to this interface and you may get some kind of benefit from it. What that is, is really tough to say without knowing what you are recording and exactly how.