There's various aspects to stringed instruments and how they get their tone. Most importantly is the player themself. A great musician can play any brand of instrument and still sound like themselves...and still sound amazing. For stringed instruments you have wood quality. What type of wood and how long has been drying. One of the key ingredients I have found is the older the wood used in an instrument, NOT how old the tree is, is key to getting a great tone. Wood that has been allowed to age and dry vibrates easier and fuller than wood that is still "wet". That's part of the reason the older stinged instruments sound so damn good. The same thing can be said of making amplifiers using the same wood; resonance. The technique and ability of the maker comes into play of course. But the one thing a 1959 Strat and a 1720 Strad have common is wood that's had a long time to age and mellow.
Remember what Gus McCrae said, "The older the vioin, the sweeter the music."
