Small tone and volume problem

I've been playing bass for about a year and a half, i'm just about ready to start gigging, using my kustom kba 100, and samick active bass, however the tone I dig is becoming a problem when trying to play at a higher volume, usually to gain it i'd either turn down the bass's volume for a neater sound or just play quiet, now as soon as go to turn up on the amp, my clean and bright tone is destroyed giving away to white sound and abrasive more distorted sound, (the amp has a gain and volume control for overall volume), I want a neater, brighter and cleaner sound, I think a supressor/limiter maybe a safe option as it (if i'm not mistaken) equalizes tone, Imainly play slap, and the tones I lean towards are reminiscent of Jaco Pastorius, clean style Geddy Lee and early Les Claypool, I know they may seem different but I feel they have connection in some way, any help would be much appreciated, cheers

P.S I also use a Aphex Xciter, which I believe may be able to work in conjunction with a compressor , which would create a "companding" effect, hopefully edging the tone to one I'd like more, is that correct?

 

so will getting a compressor make my tone brighter, and more like Jaco's in any way?