Your old strings were probably higher tension, so the combination of low tension, roundwound, and newness is giving you the buzz and clank. A few things you can do: give it a few weeks and let the strings break in, adjust the string height to be a bit higher and/or adjust your truss rod so that your neck is straight, turn down your treble a bit and roll off your bridge pickup. If after a while you still don't like it, get higher gauge nickel strings or better yet, try flats.

I personally can't stand buzz, clank, and tinniness (is that even a word?). So i switched to flatwound many moons ago and never looked back.