Yes you can. Probably the best way is to remove the whole focusing assembly, otherwise once you remove the stage, you will have the sub-stage (where the condenser is) in your way. To remove the entire focusing assembly, you will first need to remove the sub-stage. On the left hand side of the sub-stage arm you will see a tiny set screw. It should be a flat head one, and you don't need to remove it all the way, but you have to back it of a ways. Once the screw is backed off far enough, the sub-stage can be lower down to a point at which it will come off. That will expose 4 hex screws; remove those 4 screws and the entire focus assembly will come off.

That should give you enough room for a violin to fit under it, but you are still going to have issues with focusing in on it. With the focusing assembly gone, there is no way to easily adjust your focus. You will literally need to act as the focusing assembly by lifting it up, or pursing it further way. You will also run into an issue with light... there isn't going to be any, but you can use an external light source from above, like a desk lamp or better yet a flash light; something that has a focused light would be best. Ideally this would be a fiber optic light source.

If you haven't already bought a microscope yet though, I would strongly consider getting the right type of microscope for this, which is a stereo for magnification of 100x or below, or you could do it will a transmitted inverted metallurgical microscope for magnifications above 100x. Where you might be able to get the micromaster to work, it really isn't the most ideal candidate for this type of application.