The red brass neck sounds a bit different but not by much. Jupiter had a variety of different necks 10 - 15 years ago. The most difference makes the nickel plated brass neck or if there is additional weight added on the neck like the heavy I or II version. Obviously they have all the same inner dimensions and this much more critical than different material. I played them all on my XO-2089. I still prefere the original brass neck. Don't expect a massive change of sound.
Alphorn
Alphorn
