Dynacord Rhythm Stick / Jamma

[PaulF707]

Hi
Anyone remember these from the 80s?

http://www.thejamma.com/

I always quite liked them - I played one a few times at shows in the 80s, and even tried to build my own in the 90s (using an old Alesis D4 as the trigger interface).

I was wondering about 're-starting' this project using a MegaDrum interface...

The basic principal of the Rhythm Stick (and how it differs to a Zendrum) is:

The main velocity input is a pair of piezo pickups (linked together to provide one input - the only reason there are two is to allow fast playing by alternating between the thumb and fingers).
This trigger signal is then fed through a matrix of switches to select which sound (i.e. trigger input) is played.

Because of this configuration, one trigger signal can be fed to up to 4 or 5 trigger inputs (but in reality 3 is the most likely maximum).

Would this cause a problem for the MegaDrum brain? Would the outputed midi velocities reduce as more triggers were selected?

When I built my own in the past, my Dad designed a complex transistor based circuit that was supposed to keep the output of the piezos consistent regardless of how many inputs were selected. However, this never worked and so I simply fed the piezo output to the inputs on all the switches, and the outputs to each of the D4 inputs. It seemed to work OK.....


Yes, I know this input configuration can be quite limiting (all simultaneous sounds are played at the same volume etc) - but it is fun to play, and can produce quite a nice groove. I would probably extend the design to have some additional triggers (like a zendrum) - particularly for cym crashes etc) - so I'd end up with a combination of both.

Any thoughts on the viability of triggering a MegeDrum brain in this way (one piezo fed to multiple triggers by switches) would be greatly appreciated.

Cheers
Paul

[dmitri]

The signal level (and eventually velocity) on each input will weakly depend on how many inputs connected to one piezo since each input adds a load on a piezo. More importantly the output velocity individually on each input will depend on levels settings on each input. So even though all these inputs are connected to a single piezo, the output velocity on each input can be different.
Btw, any reason to do it like that? You know that you can configure sampling software to trigger several sounds on a single note.

[PaulF707]

Thanks, that sounds promising....

The reason for this design is that you can play rhythm and velocity with your right hand (without having to worry about accuracy of where you are hitting).
You then use the buttons on the left hand to select which sounds to play (typically hold hihat or ride sounds with the thmub, and then play kick and snare on relevant hits with fingers).
It's a different style of playing to 'real' drums (and even to Zendrum type 'pad per sound' triggers), but I find it quite intuitive, and produces a good groove.

I'll give this some more thought.....

Thanks for the feedback