Ashdown DI connection issue

Hi guys,
New to the form so apologies if this is in the wrong place.

I've got an Ashdown FiveFifteen Big Boy head connected to a Mag210T cab.

Ive had it a couple of years and regularly DI it into a PA system for rehearsals. Today during rehearsals there was a horrible loud buzz coming out of the PA speakers. Turns out after a lot of changing cables etc it's my DI output that's causing the noise.

It's not coming out of my cab, just the PA speakers where its DI'd to.

Would anyone know what the issue is and if it's a quick fix or am I best taking it to a shop and letting them look?

Thanks in advance!

 

It doesn't look like it. I've attached a picture for you.

 

Cheers bud I'll look in to it. It's odd cause it's never done it up until today!