I know this question may spur tons of claims about me not maturing my embouchure or blowing completely wrong. I have been trying to play my Conn Director that I bought off eBay for 2 weeks now. I've noticed that every time I buzzed into the 7C mouthpiece the tone that comes out of my horn is unclear and hard to play a normal note. I'm just starting out learning to play the trumpet, I haven't even taken any classes in the past or had any lessons, but I'm gonna give myself a wild guess that the unnatural sound coming out of my trumpet is due to the fact that my water keys/corks/other parts are missing? Also my tuning slide is a bit hard to pull out even after I have put a lot of valve oil on there, but I don't think it makes much of an impact on the tone.