If
you've built circuits before, you can make your own external one. It's
a very simple circuit. Go to National Semiconductor's website, and
look at the data sheet for the LM833 chip. They give the the actual
riaa preamp circuit. They also have a schematic for a two-stage riaa
preamp although slightly more complicated, but that should be even
better than the original b&o one. For the spot on the circuit
where it asks for plus and minus power to the chip you can just use two
nine volt batteries (one for each polarity). And since you're making
the circuit yourself, you can put the DIN connectors on rather than the
usual RCA. In the end you might still spend about as much as you would
pay for a simple external one (about $50 if you pay for a nice
enclosure, less otherwise), but sometimes it's fun to make stuff
yourself, and you'll get to have DIN plugs on it too.
Austin (camshaft)