The Longhorn was on my want list when it became extinct. I am looking for a new cartridge...
Well, the Longhorn isn't really extinct, even if AVA no longer makes them. One of the back issues of Audio Basics has the recipe. Frank has them indexed on the website.
It is really easy to make. First, you need a cartridge with a flat front. Grados fit the bill, plus they are really good cartridges in their own right. Take a 1/4 inch brass u-channel - generally available at your local hardware store. Cut a 1.5 to 2 inch length. Make a notch in the center that closely matches the cartridge width about 1/2 to 3/4th of the way down the "U" part of the u-channel. A file works well for this.) Add a gob of solder at both ends. (Here's where the ability to gob solder is actually an asset!). Fill the rest in with plast-i-clay, then glue the u-channel to the front of the cartridge. (I generally use rubber cement, since it is reversible.)
Couple things to watch out for: 1. That your arm can effectively counterweight the mass (generally not a problem unless you decide to build an especially big longhorn) and 2. that the arm, when attached, won't actually bump into anything like an armrest, etc.
