Yamaha MR-10 bass drum trigger input question.

[bionary]

I'm trying to trigger the bass drum on my Yamaha MR-10. I can trigger it using the trigger out of a Korg-KR55 and the TR-707. But when I plug the output of the triggering machines in, it no longer triggers the MR-10. Any suggestions? Thanks.

[micahjonhughes]

What do you mean by "I plug the output of the triggering machines in"? Could you more fully describe the connections?

If you are just pluggin in (for example) the kick out from the 707 into the triggier in on the MR10, the kick out may not create a stronge enough voltage swing to trigger the MR10. This is why the trigger outs are provided.

[bionary]

I have the trigger out (of either the Korg KR55 or Roland TR-707) plugged in to the bass drum trigger in on the MR-10. The audio output of the MR-10 is plugged in to a mixer channel. This works fine. The bass drum is triggered on the MR-10 when I press play on the KR55 or when I tap the Rim button on the TR-707. When I plug the output of either the Korg or the Roland in to a mixer channel so I can hear them both (the 707 or KR55) and the MR-10, it no longer triggers the bass drum on the MR-10.

[micahjonhughes]

Here is the schematic for the MR10. http://www.loscha.com/images/MR10-Schematic.gif

The BD Pedal is not a normal trigger in. It is looking for a switch to be closed to trigger the bass drum. Closing the switch creates a pulse.

The 707s trigger causes the MR10 pulse shaper to fire, as there is a voltage differential on between the tip and ring because of the +5 pulse.

I'm not sure why the pulse shaper works when both are not plugged into the mixing board, but I'm leaning towards it being a grounding issue.

What type of cord trs or ts (i.e. stereo or mono) are you using to connect the 707's trigger out to the MR10 Bd pedal?

[bionary]

I'm using a mono cable.

[FX23]

midi it

[bionary]

Are you the same FX23 that's on GearSlutz? If so, were you able to find the mods for the MR-10?

[bionary]

Does anyone have other suggestions?

[oortone]

OK, this is pretty old but I think I know the problem since I almost did the same mistake, but with all the pads too.

I don't really understand your signal path but the almost correct way to do this is to convert the standard V-trigger from say a TR707 to S-trigger (which is lika a switch). This would work with the BD input and also with all the pads if the unit is opened and the trig is connected to the pad contacts of the PCB.

HOWEVER THERE IS A BIG PROBLEM!

The MR10 internally works with -9V, and this is also used on the pads and the BD input. So what will happen is that -9V needs to be connected to the negative side of the S-switch output. This is equal to GROUND and via the shields of the trigger AND audio contacts of your equipment this will eventually end up on the shield of the audio contact connected to the MR10. But the shield of the MR10 is (as for most units) equal to ground and this will short circuit the -9V supply on the MR10 and it will not work. May even be damaged.

I guess something similar to this happened to you too, although not with a proper V-toS-trig converter.

I believe one needs to opto isolate the trig inputs somehow but I haven't got a schematic at the moment.

[oortone]

Here's a solution for the problem, five of these. This will convert standard V-trig so the drum pads can be triggered. The -9V is the internal voltage in the MR10, it can be obtained at the PCB on the switches. Note that BD-connectors are reversed in relation to the others. The optocouplers are Vishay ILQ55 & IL5.