Only few people may agree but I firmly believe good sound comes from high current not high watts even though inter-related to some degree.@hifineubeeThere really isn't any such thing as 'high current'; that's a bit of story created by solid state amp manufacturers. Current does not exist without voltage, and together the two are power. Its a mathematical relationship!
The reason 'neutral' (usually solid state, as opposed to 'warm') might seem unpleasant is due to how the amp distorts. In the case of solid state, the distortion seems minimal, but to the ear it is not, as the distortion in question is all higher ordered harmonics, to which the ear is keenly sensitive (the ear uses these harmonics to sense sound pressure, so has to be able to deal with 140db range, hence the sensitivity). So 0.0x% numbers in solid state amps are easily audible, heard as brightness and harshness.
Tube amps generally don't make as much higher ordered harmonics and so sound smoother and more detailed. Tubes usually do make more distortion overall, but its mostly lower orders and the ear simply is less sensitive to the lower orders. In a way, you can argue that tubes more closely adhere to the rules of human hearing perception. In a nutshell.
I'd be looking at something with 60 watts or so. You can find amps of that power inside of your budget, and that is significantly more power (and likely lower distortion and wider bandwidth too) than what you are running right now- you'll notice the improvement instantly!