Is it the equipment?
Yes.
To understand why we will need to drill deep down into the details of exactly how a violin makes music. It’ll be worth it because a lot of the same things happen with a lot of other instruments, just not quite to the same degree. Which is what makes violin so hard to do right.
The violin bow is a bunch of rough textured threads. Its not one thing. Its a bunch of them. That’s why you sometimes see them all frayed, as some wear through and break, the ends fray and frazzle.
As the bow is drawn across the string its not a smooth motion. As each little rough bit grabs and lets go its more like a series of tiny little plucks than a steady tone. Its all these transient spikes within the tone that give violin its character.
In order to reproduce this well it requires the entire system be fast enough to accurately reproduce each one of those micro transient spikes, then die down fast enough to reveal the underlying fundamental tone, as well as the resonance of the body of the instrument. This is asking way too much. The vast, vast majority of components get the transient, render it too harshly, smear it so much the tone and body are lost, wash rinse repeat. All day long. Its crap. Its why hardly anyone wants to listen to classical.
Its sad how hard this is to do right. My system didn’t get there until I got the Moabs. Even then it would not be there without all the many many tweaks and mods to every inch of wire, every component chassis, on and on.
So yes its your equipment. But not just the amp, speakers, etc. Equipment includes every inch of every wire from the breaker panel to the speaker cone and every component in between and all the stuff they sit on and the room the sound is heard in.