I recently purchased a small Yamaha stage pass PA. At the moment the only thing I use it for is vocals. I'm just a home noodler, so it's just used so I can sing and be heard over my guitars. Anyhow, I was surprised at just how good this little PA sounds and starting thinking I should put a modeler in front of it just to see how it turns out so I'm looking for some suggestions. I would like to stay under $500, but could go over a little if necessary. Thanks.