Amp help emergency

[Bearstripes]

Hey everybody kinda in a bind here and am at a total loss.
For the longest time my bass amp as been a traynor bassmaster into an old hartke 4'10. This was my rug forever and it had head room for days and sounded great.

In more recent times the hartke has since left and I picked up an ampeg svt 4'10.
So here's my problem. The ampeg has only been used at bedroom volume, no louder than one except for like once or twice. So I get it to practice and give it a lil volume and the sound I get is like instant shit. With the hartke I could compete with a cranked twin and an ac30 and never have to turn it up past 3 (10 o'clock). I had it above noon and it still wasn't loud enough and distorted as all hell.

Now I'm pretty sure that the traynor is eight ohms and I know that the hartke was 8 but the ampeg is 4 ohms but as far as I know that shouldn't hurt anything.

Any thoughts on what's wrong would be awesome.
Thanks

[AxAxSxS]

describe "instant shit"
does the amp make enough volume?
Is there a lot of hum?
Does it make noises on its own?
When was it last serviced?
Which version of svt is it and when was it made?

[MEC]

If the Traynor is 8 ohms the cab should be 8 ohms too.
You won't hurt the cab but you could fuck up the amp.

http://www.legendarytones.com/ohms.html

[Bearstripes]

By shit I mean not loud enough and very distorted. My low e just buzzes. It was probably serviced like three years ago maybe four. The ampeg cab is only like four years old

[D.o.S.]

If the Traynor is 8 ohms the cab should be 8 ohms too.
You won't hurt the cab but you could fuck up the amp.

http://www.legendarytones.com/ohms.html