I have a korg sq1 and a Pittsburg lfo2, and I will get more modules later. But right now I can't get the sequencer to interact with the lfo2. Does anyone have experience with either or both? It seems like both units only have outputs.

This is probably a stupid question and has probably been asked before, but what all do you need to make a simple modular synth? Will just a sequencer, oscillator, and amplifier be enough, or will I need filters or anything else?
Thanks