Stupid ampeg head question. Don't hate me

OK, I am not an amp guru by any stretch, so bear with me. I jsut bought a new cab, tried it at the store with another Ampeg SVT-3PRO, sounded fine. Got it home, it sounds very distorted. I know there is a number of things that could be wrong here, but I am seeing this as an amp problem. What should I look for first? Sorry I didn't read through thousands of ancient posts looking for answers. I figure anyone who knows anything will spout of one quick answer of the top of their head and I'll be in business. Thanks

 

Actually, I must bring this one back from death. So it distorts when the graphic EQ is switched on, but not as much when its off. Also if the 15db cut is on the the EQ is off, it sounds more or less fine. The gain knobs seem not do do anything. What gives?

 

The gain knobs did do stuff before, and did with the amp I tried at the store. I guess what should say is adjusting the gains doesnt seem to help the distortion IT is changing the volume. I wasjust screwing with it and keeping the input gain nearly off and maxing the master volume with the eq off caused a small amount of distortion, but at anywhere near playable volumes it gets pretty noticable and seems to get worse as I play.

Fdeck, starting to think that the trip to the tech is in fact in order. IF so, what kindof work do you think will be needed? What should I expect to be paying here (I am an easy target for getting ripped off, as this is the only head I have ever had a problem with)

 

The amp was in storage (in a house) for about a year, worked before it went back. The cab is 8 ohms. I can set the tube drive anywhere and it still distorts. The more volume, the worse it gets, but it starts at pretty low volumes and is not just from cranking all the gains up. I have neither the high nor low switch engaged. Like I said, I tried the cab with an identical (if a bit newer) 3 Pro at the store and it sounded fine with the tube gain cranked, input gain at about half and about half volume, which I can't even get close to with mine.

I bought this head in high school and nothing has been done to it, so its not outside of hterealm of possibility that it needs some kind of normal maintenance, I just am not sure what.

 

I can't find a battery. Do you know where Rickenbacker puts them?

(sarcasm)

 

Thanks guys, I'll take a look at whats been recommend and see where that gets me. I was hoping not to have to replace tubes, but I figured this was a possibility.