I was following the the very excellent “Renoise 3.0: Creating a layered instrument” tutorial and created the instrument. But, I get this tick noise whenever i play a pattern. I loaded up the Drawbar Organ instrument and it does the same thing. I was wondering if anyone else can hear this tick sound and how I could get rid of it.
There is a simple solution to this: silence any previous note in a note-column before playing a new one.
So, if you were playing something like this:
C-4
...
D-4
...
E-4
Simply do this instead
C-4 OFF
... ...
OFF D-4
... ...
E-4 OFF
Essentially, flip-flop between note-columns to avoid overlapping notes.
–
Technically, there are two factors that together contribute to the clicking noise:
Firstly, we are dealing with a pure sine-wave. They are notoriously sensitive to everything you do, including setting volume, panning - everything can become the source of unwanted clicks, and has to be carefully avoided with very slight transitions (ramping) between values. Often, you can reduce the clicking noise of a sine-wave yourself by adding an ADHSR device and configure it to a slight amount of attack and release.
Secondly, and this has has more to do with the nature of Renoise, the Drawbar organ is comprised of a total of eight layers. So, if you play any single note in a note column, you will be actually be playing 8 “voices” (each note column in a track supports playback of 12 voices). This seems to be the reason why triggering a note in that same column will cause an ‘extra noticeable’ click: the moment the new note is triggered, it will have to “steal” 4 voices.
In an upcoming version of Renoise, I hope to see some new kind of “voice-pool” approach so we don’t have to worry so much about this 
Sine sounds sooooo good, but when it unintentionally distorts it sounds soooo bad. 
Sometimes the glide command can be your friend too, but it’s obviously not a solution for every situation.