AD30HTC gain???

[boiler]

I just got the ad30tc head and it's OK, but when i connect it with a marshall 4x12 cab. and then turn the gain above half its starts to make strange noises like my speakers are torn apart..
I did connect it to a bassman 2x15 cab. and it was OK, but with a vox cab. it did the same.. I checked the marshall cab and it works fine!
I don't get the problem here, it seems there is a problem with the gain.. normally the marshall (280W) should be able to handle the 30 W amp?
When i play through a big muff, and less gain it's OK.
Anyone please help me to solve this...
Thanks

[gearnut]

So are you saying to sometimes happens with the Marshall or all the time? Your post is kind of confusing. What kind of marshall is it?

Anyway, it could be the preamp tubes. Is it on one channel or both? Try swapping them out and see what happens. If it's only one channel, just take the frontmost tubes and swap them with rear ones. See if that makes a difference. If it does, it's the tubes.

Make sure you have the cab plugged into the correct ohms jack. The bassman cab probably isn't 16 ohms (4 i think, right?, so you're plugging that into the 8?), so if the marshall is plugged into the 16ohm jack, maybe you have a bad solder or jack or something like that in the 16ohm jack. Just a thought.

My ad30htc works fine with both of the marshall 4x12's that i have with gain dimed.