"Unit has the JL Cooper midi mod installed, which allows for midi clocking the internal sequencer and for triggering drum sounds."
via Johan.
Update via kb in the comments:
"LinnDrum is definitely digital, but actually has quite a bit of analog control for it's digital voices:
- uses analog filters (CEM3320's) on bass, tom, and conga voices
- uses analog VCA (CEM3360) for highhat decay.
One pb with the LinnDrum is that all voices weren't pitch tunable (like they were on the LM-1), but I just modded my LM-2 this weekend, and now they all are."