How can I get a clearer sound from my guitar amp?

I have a Belcat 15 or 30 Watt amp (****, I know but it's only a practise one) and a Digitech RP90 all in one pedal thing. When I use it the sounds are abit muffled. Only abit but it's noticeable. How can I get a good rock, clean and metal tone out of it?How can I get a clearer sound from my guitar amp?
Like the other dude said, a better amp will be the only real fix. Just keep playing what you have until you can afford something else. You will always need a practice amp so you can keep what you have for that. I would suggest a nice low watt tube amp like a Fender Blues Jr. For home use and small gigs it is hard to get a good sound out a higher output tube amps since you cannot turn the volume up enough to saturate the tubes. I have a 15 watt class A Fender Princeton that gets really loud and sounds incredible. Class A tube amps will be louder with the same amount of watts compared to a class A-B tube amp. Solid state amps are fine, but you will never get that ';tube sound'; out of one.How can I get a clearer sound from my guitar amp?
You have what you have. The only way to upgrade the sound is to buy up. What you have is still okay to practice on. Watch craigslist and you'll see all kinds of great Amps for sale.