Some amps are relatively transparent though , others have more distinct character. My Forte sound is largely determined by the bass I’m playing. More so than some other amps I have.
There are many that use a power amp with a completely separate front end /preamp.
edit The Forte does not suck the vintage out of passive basses , if you want to add an additional gain stage you can simply add the pedal or preamp of your choice , I run mine just as it is. It possesses some serious slam , and I find the EQ on the Forte almost surgical when it comes down to dialling things in.