Wierd noise when using a 6505 with a loadbox

[Flow Of Time]

Hey guys, I didn't use my 6505 for about a year. I always used it with a loadbox.
Wanted to play a bit with it again today, but after about a minute there was some high squeeking noise coming through my speakers.
The ampsignal was not totally gone, you could here it beneath the squeeking.

Does anybody know what that could be? I'm kinda scared to turn it back on right now..

Btw: The signal goes: powerampout -> di box outlink -> loadbox
and di box balanced output -> interface

I had the gain cranked pretty high on the interface about 9 o' clock

I'm also running a tube screamer before the amp, maybe empty batteries, but I don't think tha's it^^

 

[NecroDM]

I may be wrong but sounds like the signal is getting lost along the chain, have you tried disconnecting both the loadbox and the TS and just plugging the guitar and the amp on a cab?

That way you could check whether the problem is with the amp itself of if it's something else.

 

[Flow Of Time]

I hope that it's something like that. As I'm writing this I remember, that the cable going from ts to amp is damaged..
I'll try it!

Thanks for your answer

Edit: Can i use a line cable as an instrument cable?
Edit2: Works, I think it was the cable then, thanks!

 

[NecroDM]

Cool, glad that was it

And I think I also need to replace some of my cables as I'm getting more feedback that i should