AMPEG BA115HPT hissing problem! HELP!

[droian]

I have a huge problem with AMPEG BA115HPT i.e. tweeter is hissing badly. It is not usual situation when horn hiss a little bit. I had bought new tweeter and the same situation happened. Is there such possibility that it is the tube fault? (15” speaker sounds good)
or is that something else:/
How can I get rid of this hissing problem??? (without disconnecting the tweeter)
I use this Ampeg for a 1,5year, and I didn't have this problem in the past.
pls help!

 

[droian]

I should also say that:
This happens only when I am playing.
This hissing is more like buzzing:/

 

[martyman5000]

Mine hissed also...unplugged the tweeter