Analogue-sequencer

Try this using the drum machine as a buffer to 'boost' the signal:

midi merger -> drum machine -> P3 -> to wherever

I think the midi merger's signal is close the limits set by the midi
spec. Some machines will work well with it. However, the P3's opto may
not be quiet fast enough to recover the midi clock signal to work the P3
correctly. Your drum machine may boost the signal level.

You could insert any 'midi through box' like a synth or whatever in
place of the drum machine too.

Regards,

Tony Allgood                           www.oakleysound.com

Oakley Modular Synthesisers      Penrith, Cumbria, England