Thank you, Tog_ and Acolyte for your input.

I wound up getting a Shure M78S cartridge with a 2.5 mil diamond stylus. It tracks 78s quite well at 45 RPM and 2.5 grams.

It was advertised as a monaural cartridge, but a little research revealed it's mono due to jumpers on the signal pins. Removing these jumpers makes it a stereo cartridge. After finding this out, I ordered a Shure N70B 0.6 diamond stylus, which is for LPs. So now with a quick change-out I can play 33 1/3, 45, and 78 RPM records.

The Goldwave software does a fabulous job of changing the signal from 45 to 78 RPM. The sound is very smooth, accurate, and artifact-free, except for those artifacts from 78s that even the best noise-reduction applications can't remove.

A bit of web research showed that, as suspected, there's a slight bass roll-off doing this, but the higher frequencies are actually improved since the stylus tracks better at the lower speed. Plus the slight bass roll-off is easily compensated for using Goldwave's equalizer.

By shopping around, I was able to get the whole combo for under $45.

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