Yamaha MR10

[Circuitbenders]

Another massive analogue beatbox mod. This one is a Yamaha MR10 mounted in a 3 unit rackmount case:









Mods include:

Bass drum pitch
Bass drum decay
Snare level
Snare noise decay
High tom decay (also used as the snare shell sound)
Low tom decay
Conga trigger button (this sound not usually accessable outside of the patterns)
Toms / Conga level knob
Toms / Conga filter
Closed hat trigger
Open hat trigger (neither hat is accessable outside of the patterns)
Open hat decay
Hats Level (normally grouped with the cymbal on front panel cymbals level knob)
Hats filter
Cymbal Level
Cymbal Decay
Cymbal filter
Wide overall tuning knob (affects toms, snare, hats and cymbals)
Midi Triggering
individual outs for bass drum, hats, snare, toms / conga, cymbal

The open/closed hi hata are the same sound with the different decay triggering taken care of 'on chip' by the big synth chip. In order to trigger the open and closed hats externally you have to use one trigger pulse to trigger the closed hat with a certain resistance setting the decay, and another to trigger the same sound but with a pot switched into the circuit to control a longer decay. Then every time you want to trigger the closed hat again you need to switch the pot out of the circuit.

I've more or less got it sorted using a PIC and some logic switching to interpret the trigger pulses, but getting everything  to work fast enough and in the right order is one of those things that makes my brain feel like its about to dribble out of my ears even thinking about it for too long.

There will be a write up and demos on the main site once i sort out some bugs with the triggering.

[Paradigm X]

Wow! 

Had to register just to express my amazement at this project!

I grabbed an mr10 for £20 which seems to work intermittently, and was hoping to trigger the sounds, some really nice sounding drums.

But thats just ridiculous!

Amazing.

[Paradigm X]

Hullo !

Mine was quite damaged due to a leaking battery, but ive fixed it and recapped it now and it sounds amazing!

I found one mod on the net, the Cymbal Decay, which does lead to a couple of potential other mods.

Are you going to detail any of the other (simpler) mods?

Many thanks, Ben

[valvusmusicus]

Hi All
This is Awesome!!!
I cant work out how you manipulated the sounds so much-its based around a YM1023 Rhythm Generator ROM-how did you get all the access to the tuning ( Ican, to  a certain extent understand the levels and tone manipulation)
Be great to know

CHeer
V

[Circuitbenders]

I know this was posted a long time ago, but we ran into some issues with the midi triggering and then i got distracted by other projects that needed to be finished a lot more urgently. There will be a write up on this on the site as soon as i get a free couple of days to finish it off.

If i recall correctly most of the sounds use a resistor and cap arrangement external to the main IC that sets the decay.  The IC has a dedicated pin for the decay of each sound. Just swap the resistor for a pot and you've got a decay knob.

[valvusmusicus]

I know this was posted a long time ago, but we ran into some issues with the midi triggering and then i got distracted by other projects that needed to be finished a lot more urgently. There will be a write up on this on the site as soon as i get a free couple of days to finish it off.

If i recall correctly most of the sounds use a resistor and cap arrangement external to the main IC that sets the decay.  The IC has a dedicated pin for the decay of each sound. Just swap the resistor for a pot and you've got a decay knob.

Hi
Thanks for the reply-I have played around with that mod, and had some good results
I was wondering if its possible to play around with some of the glue logic chips, feeding the data lines of the main Rhythm chip (I think its the YM1023) to get different sounds/patterns out of it. Also, there is an output on that chip(pin 4) that may have another noise/tone output
Also, what do you think about switching out one of the Tom sound output lines to change the sounds?


Regards

V

[valvusmusicus]

Hi Again
Sorry, I know you are busy-so answer this when you can-this circuit just fascinates me (sad, I know!)
FInal question-I understand how to do most of your other mods-but-the BD output pin (O4) on the YM1023 chip, does not seem to be connected to anything in the circuit diagram!
Also, cant seem to figure out how you adjust just the BD pitch, indeebdant  of the other voices

many thanks

V

[Circuitbenders]

The bassdrum output pin is pin C4, which sends a trigger to the actual analogue bass drum circuit. This is the oscillator that you can see to the right of where it says Bass Drum Filter on the schematic. The word 'filter' is a bit of misnomer there, as thats the whole bass drum circuit. Replacing R66 with a pot will give you a decay control. i used a C10k pot in series with a 2K7 resistor.
Note that the BD trigger from the front panel button bypasses the YM1023 and goes straight to the bass drum circuit? Thats because the sound is generated outside of the chip, and the triggers from the preset patterns and the front panel button are mixed just to the right of C34 on the schematic.

You might want to check out what the trigger signals actually look like on a scope before swapping them around, but i don't see why it shouldn't be perfectly feasible.

[valvusmusicus]

Hi Crustypaul-aaah--thats why you can adjust the tuning of the BD, cos its bsaed around that analogue circuit
Thanks very much for that-Ill now start moding and post my results when done

Regards

V

[Timbob]

Hi all

I too have been working on this little machine. Was planning on making an arduino sequencer, but ran into some problems.

I got this far:

https://www.youtube.com/watch?v=PBXA5TGVQaw

I tried different methods of triggering, this time with 4066 ic's, but i noticed the sounds where a lot softer. And when connecting, i heard a slight pop, as if it was half triggered.. weirdly.

Also, when syncing to other midi devices, I noticed a lot of lag. but that could be my arduino coding. I just started with those, and wanted to make one from scratch Was amazed I got this far

Also: when I tried to ground stuff, I fried my 4066 IC's. Probably because the MR-10 has Ground and -9 volt...

So, If anyone has another option of triggering those sounds? I'd be very happy
_{(if anyone knows how to place youtube on this forum... also welcome}

[Antichambre]

Hi Everybody,

Just for you to know that you can add SYNC to the MR10.
Forget everything about internal Master Clock, it's just for logic circuit!
Remove the RC osc at TCL(pin7 on IC7) by disconnecting the yellow wire from pot TEMPO and removing C11
Inject a clock at 48ppqn to TCL, for example 96Hz for 120BPM, 96*60/48=120.
this clock has to be between 0 and -6v. Don't use a TTL signal directly!!! You've got to reverse it and gain it a few. Do not exceed 0V!!!
That's all
You can make the same thing for the common tuning, except that the frequency has to be from 125KHz to 250KHz(original freq range), you can increase it to 500KHz max and decrease it to 15KHz. this increases the tuning range. use a PWM from a uC as  PIC or other. Take care of levels.
For both, i use OPamp for gain/reverse the two clocks from the uC, i also changed the supply to a true +5v/GND/-9v

@Circuitbenders: For the BD you swap R66 for decay but it seems to be for filtering(pitch), no? Then what about the decay?

Best regards

[did concombre]

thanks for those informations!
I have a question about the mr10
Does someone already tried to invert the -9V / ground to ground / +9V ?
Could it be done without harming the machine and without a lot of modifications (ie : capacitor swaps for example)
This could be a really cool way to begin to modify it, no?
The few tests I've done were not really conclusive because of this unusual polarity...
thanks anyways for the mods.

[AIRINESS]

who know how pur a midi in sync in this one ?

best

[oortone]

thanks for those informations!
I have a question about the mr10
Does someone already tried to invert the -9V / ground to ground / +9V ?
Could it be done without harming the machine and without a lot of modifications (ie : capacitor swaps for example)
This could be a really cool way to begin to modify it, no?
The few tests I've done were not really conclusive because of this unusual polarity...
thanks anyways for the mods.

Using an V-to-S-trig from an external sequencer can be used to trigger the BD-input and also all the pads. However there's one big problem (kind of discussed here: http://forum.vintagesynth.com/viewtopic.php?f=5&t=71497&p=808446#p808446). Since it's -9V the S-trig converter will often shortcircuit to the MR10's own audio shield when connected with other gear. This is because -9V ends up at ground in the S-trig converter.

Does any one know the best solution to this?
Maybe an optocoupler, but how?

[oortone]

I found a solution for V-trig with optocouplers so there are no voltage loops via shield. Will report with schematic as soon as I've installed and tested.

One thing I wonder though is if it's possible to separately tune the bass drum. It does not follow the other sounds when they are tuned and since Circuitbenders mod has a tune knob I realize there's a solution. Maybe R67?