Well, to be fair sometimes a re-tipped or replacement cantilever will sound better than the original. But to invictus005's point (I think), you simply have no way of knowing what your cartridge will sound like after altering it.
New or used cartridge
I have have good experiences buying a previously owned cart in the past, but have heard several telling me to buy new.. I wish there was a way, to tell how many hours was on a used cart. Other than putting the cantilever under a microscope, I see no way concerning the hours/use/condition of a used cart.. I kinda look at it as buying a used car. Let someone else take the initial "hit". then buy from them, as they're moving over or up. I have an excellent Koetsu Urushi Black I'm going to put up for sale. I love it's sound, but am wanting to move up the ladder so to speak.
Please give me opinions concerning this.
Please give me opinions concerning this.