Every trumpet has a sweet spot where it will play the best. I think 1-1/2" is out a little far for the trumpet to play at it's best. I think it's either a mouthpiece problem or maybe the trumpet is a little more open that you are used to. If you choke off a little bit, that will raise the pitch. If it's you, the problem will go away with time as you get used to the trumpet. On the mouthpiece side, there might be a mismatch with taper on the mouthpiece and the receiver or too much gap. I would be surprised if a valve alignment would help. By the way, there is nothing wrong with tuning to "A"