It comes to my attention this iOS app. It’s name is Ruismaker, a “hardware” style drum synth module from Bram Bos, the creator of HammerHead Drumbox and Stomper Drum synth, you should know about those if you did electronic music on the 90’s.
"…an Audio Unit Instrument for mobile DAWs and sequencers.
There is not a single sampled sound on board: everything you hear is synthesized in real-time by emulating classic analog circuitry – giving your beats that little bit more soul.
True to its hardware roots, Ruismaker’s design philosophy is still about making music: quickly getting a groove going and tweaking the sounds to fit in your mix. All the complexity stays under the hood."
So far I´m testing it with MOD STEP and it sounds delightful!
If you want some food for your Octatrack and other devices that supports samples give Ruismaker a try. It only cost 4.99 
Best!
