My 103M has the usual Denon tapered alloy cantilever. The boron part is the 1 piece armature (coil bobbin and cantilever receiver tube). Boron is black, but the photos online clearly show a silver/grey coloured cantilever. This is not to diminish the efforts of Denon with the 103M. Indeed, it's the only cartridge I'm aware of that uses a boron armature.
I may have that one confused another Denon with the boron tube, maybe the DL-1000. I don't have the paperwork on the 103M, just a broken cartridge.
The DL-103M did (originally) have a boron tube cantilever, but some may have been repaired with an aluminium alloy tube cantilever by a previous owner. In order of cost, here were the Denon cartridges with boron tube cantilevers, cheapest first:
DL-103M – amorphous boron pipe cantilever (Denon's description)
DL-207 – amorphous boron pipe cantilever, 0.25mg moving mass
DL-305 – amorphous boron pipe cantilever, 25 micron wall thickness, 0.168mg moving mass
DL-1000A – amorphous boron pipe cantilever, 23 micron wall thickness, outside diameter 0.3mm, 0.077mg moving mass
These all used Denon’s patented method of vapour-deposition to produce boron tubes, with the DL-1000A being the top model. Apart from the difference in wall thickness, the DL-1000A’s cantilever length in front of the coil bobbins was roughly 40% shorter than the DL-305’s, which contributed to its lower moving mass, and its nude stylus tip was shaped from a tiny 0.06mm square diamond rod, versus the 0.05 x 0.1mm rectangular diamond rod the DL-305’s tip was cut from.
Denon and Technics were the only manufacturers who perfected boron pipe cantilevers, and both used similar methods to manufacture them, which they both patented.
Edit: I've rearranged the order - apparently the DL-207 was more costly than the DL-103M, according to High Fidelity magazine's 1984 Stereo Directory. We all make mistakes...
