www.megadrum.info

Am I right that this scheme is compatible with a Roland-module, and also works with MegaDrum?



I'm really trying to understand how it works, but could not fully understand it..
Could someone please explain how this works? And is a 10k resistor not needed in such a diy-cymbal? I remember seeing the inside of the Roland-cymbal, which does have some resistor(s).
Hope one could clarify things a bit..

Roland style 3 way cymbal uses two stereo jacks (4 inputs), Yamaha style uses one stereo jack (2 inputs).
If it is a DIY 3-zone cymbal, why follow Roland style instead of Yamaha style?
Regardless, MegaDrum will work with both styles and because Roland style uses separate inputs for edge and bell switches, 10k resistor on the edge switch is not needed.

Well, to answer your question.. In the future I will own a Roland TD-30, so it would be nice if the cymbals are future proof. And that would make it the main reason why I would like to make it the Roland way.
I don't think a Yamaha cymbal could be easily rewired to behave on a Roland-module, allthough it'll be much easier on the inputs.

The other take would be the Yamaha-stye cymbal, which you are talking about..


I looks a lot simpler, although it's difference is all in the wiring..

So, to be short: MegaDrum knows what the difference is between edge-switch and bell-switch only by the resistor, and takes the velocity of all strikes using a single piezo?

stefan1982 wrote:So, to be short: MegaDrum knows what the difference is between edge-switch and bell-switch only by the resistor, and takes the velocity of all strikes using a single piezo?

Correct. If you're going to be getting a Roland module at a later date it makes more sense to just wire it for that - it's not as if you're going to run out of inputs with your MD meanwhile . Also, I don't think Roland cymbals have any resistors in them - they have a small PCB but I think that's just to mount the jacks and connectors on it.

Question remains that I wonder how a module (megadrum or Roland) knows when the cymbal is chocked, or when it should play the edge sound.
Any idea?

MegaDrum knows the difference by measuring the time the switch is "made".

dmitri wrote:MegaDrum knows the difference by measuring the time the switch is "made".

Right, you mean the time the switch is closed, before it is getting opened again (normally open-switch).. So, does the Roland module know this too in the same way?

Because I know that the choking of Roland cymbals is underneath the cymbal, I *suppose* that the edge trigger is positioned on top of the cymbal. Which make it 2 separate switches instead of 1, which is in the drawing above. is my assumption right that this means that a Roland-cymbal had 3 switches (bell/edge/choke), and a MegaDrum 3-way cymbal could do the same with only 2?

So, my final question would be.. if I build a cymbal like the above Roland-schematic, do I have bell/bow/edge sound and choking of the cymbal working at both the Roland-module, AND the MegaDrum TMI?

The switch under the edge of the Roland cymbal is wired to the same point as the one above it - I think it's just there to make it easier to grab and choke. That wiring in the first post should work for both, yes.

stefan1982 wrote:Well, to answer your question.. In the future I will own a Roland TD-30

Why on earth, Sir, Do you wish to own a TD 30, may I ask?