Help! My Bb and A sound hissy

[evaki]

Hi Niaven,
They are the A and Bb that you play when you have all the holes open and you just press with the thumb/left index. lol that's the long explanation....
I think you would call this the mid register in a Bb clarinet?

I don't think there are any leaks cause I play all the rest notes just fine....but on the other hand is there another way to check for leaks?

Pads are relatively new...no cracking... :-(

I am playing with a #1.5 that tseligas suggested and it treats me good so far. I also got a Vandoren B45 mouthpiece.
What do you think?
What's the difference between a B45 and 5JB? ...

Thanks