I'm a small amp freak, especially used. Picked up a Champion 20 for short bread a while back and was SO disappointed with that inert sound. It woulda gathered dust if I hadn't thrown a little rug over it and used it as a nightstand.
Until... I changed the speaker for a Jensen P8R this week. The speaker cost as much as the amp. For a cheap guy like me, this is radical. So was the change in the sound. The other folks who rated this product say you need to break these in for a half hour, thanks for the tip! I did, and the amp sounds alive. It's still neither as good nor as well-equipped as a Vox Pathfinder 15R, which I think may be the best small solid-state amp ever made; there's no line out on the Champion. But it does have useful built-in effects, and the Jensen smoothed out the peaks in the frequency response, added high and low end, made all of the four amp models sound better. I think it's well worth the price, if you're planning to keep a Champion 20 for your grab and go. Please note: I tried another replacement speaker that I had lying around first, from a Peavey Royal 8, and the Jensen is far superior.