It's hard to say what your problem is without knowing exactly what you mean by rattle. Where is it rattling? Behind the nut? First few frets and open? All over? Probably just a minor setup tweak, like a truss rod adjustment. Are they the same gauge strings? My first guess without knowing more is your truss rod is too tight, and the new brighter strings are making it more noticeable.
A couple of supportive ideas....
1. Different brands/manufacturers have different string 'builds'. Core and outer wrap can be a bit different, as well as material quality. A hex core will vibrate differently, and it will variate tension-wise.
2. If you take off all your strings at once as opposed to individually or first three/last three, it can throw off your neck tension a bit (especially if there's temp and/or humidity change going on).
If you're a low-action/E-Z player type (like me), switching from DR to DM Blue Steels will be noticeable & might need a tweak. Time to talk shop with your favorite tech/luthier and strike a balance.
Family is up now so I could bang a little harder. It is the E and A especially mid fretboard. I really had to do them all at once, one broke and the others were shot. I did it fairly quickly though if that makes any difference. I wanted to clean the fretboard as well.
'Sounds' like a slight truss rod adjustment.
If you rubbed any lemon oil or fretboard cleaner into the wood, it might've been dry and expanded a bit as well. If you use thicker guage strings, the loss of tension could've thrown it off as well as the change of brand (with it's inherent characteristics). Give it a day, and if there's no improvement head over to your tech & have him/her give it a nudge with the 'ole allen wrench.
Nah, I don't think anythings screwed up bud, new strings have a lot more brillance and high end, you will hear a lot more buzz/rattle than old ones. And if you're strings were real dead, then they'd be real mellow sounding and that's why you didn't notice the buzz.
Turn up the amp and if it doesn't come through the amp, I wouldn't worry about it. A lot of times you hear it acoustically but it never makes it through the speaker.
Is it fret "buzz" or a "rattle" in the neck? If a "rattle" in the neck I second the notion it could be a loose truss rod.... that happens from time to time... NDB if it is, just snug it up and check the relief.....
I am thinking this is the answer. I did have those two strings over tightened when I went to tune the guitar. If in two days it is not better, I will change those strings. The others were not too tight so that does make sense.