diy drum synth

Skrog Productions

Hello , I've been thinking about building a midi triggered drum sound module and toying with the idea of housing these kits / projects in yet another plywood box Very Happy

.

Elby - midi to sds trigger kit (8 outs).

2x Coron DS8.

2x T.H. mega percussive synth.

CGS Synare.

CGS chime sim.

a few simple lfo's.

mfos stereo pan.

Mixer.

I thought of putting audio FX insert jacks on each output before the mixer .

Does anyone have any advice having built any of these circuits ???

David

creatorlars · Posted: Fri Feb 13, 2009 3:03 pm Post subject:

This should work great, I have a similar setup in my modular. I added trigger outputs to my Midibox CV though, instead of using an Elby kit.

I have a master "Drum Mix" module which is basically a CGS VCA with headers behind the panel -- each drum module connects to this module to send audio to the VCA and receive a trigger which is distributed from the Midibox CV. The "level" knobs on each module function as the level going into the "drum mix", which has send/receive jacks and a couple of extra inputs. This way I can add as many drum modules as I like, and still have them be part of the master mix. Each drum module has it's own trigger input and output jacks too, so they can be used independently as well. Adding stereo capability would have been nice, but I will handle stereo mixing on a case-by-case basis -- mainly my goal was to be able to connect my MIDI In and my audio out, and have direct access and a mix of all my drum modules without patching anything.

I also reccomend the Thomas Henry Clangora -- it has a neat input trigger structure for closed/open hats and sounds great. The 808 voices are not hard to build either.

Skrog Productions · Posted: Sat Feb 14, 2009 8:35 am Post subject:

thanks, i'll check those out

I've found some XR2206 chips from hong kong on ebay for the MPS circuits and think i have most other components ( after a good tidy up of the work bench ) just have to have a rummage for a toroidal & some reg's etc to make a power supply .

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

Cool to see that there are at least 3 of us building 'drum kits'. Smile

I so far have completed:

- 1 x MPS (1 more to go)
- 1 x Liquid HiHat (2 more to go)
- 2 x T.Henry precision 1V/O triangle VCOs (with)
- 1 x Marc Bareille AD633 balanced modulator (1 more to be wired. Parts are done)
- 4 x Triple Voice Drum Triggers (8 more to go)
- 1 x Yamaha Bass Drum foot drum pad (and pedal)
- 2 x Remo Practice Pads (converted to electronic. 3 more to, in stock. More coming)
- 1 x Alesis D4 Trigger to MIDI converter

I'm currently trying to decide what to do for a mixer for them. I like Creatorlars idea of using a Ken Stone VCA as a Master Out. I still have 2 available that I haven't finished yet. I could set the pair of them up with at least 1 Inverter, for doing stereo panning between them for outputs. (I AM currently doing that for my new Quad 3 input AC mixer rebuild.)

One trouble that I now have to work out, is impact intensities to the Thomas Henry MPS.

The MPS Trigger input has the Sensitivity control for the Comparator. Depending on what level this is set at and how hard the drum pad is hit, can range from no trigger occurring at all, to full sustain. scratch

I'm wondering if this could be due to the drum pad, still resonating after being hit. A continuing resonance could be retriggering the comparator, not allowing the input capacitor TO discharge. This seems to occur when I have the Sensitivity control to set to very low. If I set it to high though, then I get no response from too soft of an impact to the drum pad.

Lots of head scratching with this one for me, at the moment. I figure, it might be best to find the Simmons SDS schematics, to see how they took care of input from the drum pads.

Sorry for rambling on and on ...... I haven't yet found anyone else to speak with about this problem and have been trying to solve it all by myself, with barely any related experience to drum pad implementing.

Skrog Productions · Posted: Sat Feb 14, 2009 10:51 am Post subject:

Ah! velocity response, my roland v-drum kit snare & cymbals make the roland module output velocity changes via midi to my korg X5 drum sounds but to implement that to an analog voice module would i be wrong in saying some sort of velocity C.V. needs to be fed to the vca to change loudness ??? .

creatorlars · Posted: Sat Feb 14, 2009 11:12 am Post subject:

Yeah, you'd need some sort of Velocity CV for loudness control.

In order to have full loudness control over every single drum module, they'd need their own output VCAs and dedicated Velocity-to-CV channels. For my purposes, this was not neccesary (and could be implemented on a case-by-case basis by just patching a drum voice through a VCA module and then back into one of my master drum mixer's auxillary inputs.) But my compromise was making the master mix a VCA... this way I could have control over global emphasis/volume for the whole mix, which is more of a common use I would have for loudness/dynamics control.

With the CV outs of Ryk's "triple voice drum trigger" you could have all sorts of fun with dynamics/CV control of drum modules.

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

I grasped the usefulness of Velocity in expression, back in the mid to later 80's and have worked with it, ever since. It helps greatly for providing impressions through it's use. I'm still trying to fine tune the related parts for it in my drum controller.
And yes, I patch it to the related VCA's CV for control of it's loudness. Also, to the filter cutoff's CV, if I wish to change the timbre of the sound in relation to how hard the drum pad is hit.
Together with pitch or almost anything as other alternatives, is where I found 3 different Decay EG's to be useful from a single drum's trigger; differing velocities being able to control up to 3 different things for each drum trigger. Smile

My final puzzle to solve with it, is creating an interface that allows me to switch from 1 CV output to another, depending on the level of velocity from the input source.. For now though, I'm happy with my current version of my controller.

Skrog Productions · Posted: Mon Feb 16, 2009 10:32 am Post subject:

great drum synth combinations Rych & Lars,
i feel left out so here's a pic of stage 1 - the box.
This will surely act as a visual incentive for me to start soldering an affordable 8 sound midi 2 analog drum module , ha ha.
I have ordered 2 ds8 boards & 2 mps boards & i'm whipping up a power supply to go in the box i knocked together in the shed on sunday .
panel will be 810mm x 140mm with a printed vinyl sticker.

Box for drum synths 1.JPG

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creatorlars · Posted: Mon Feb 16, 2009 10:35 am Post subject:

The box looks great!! I should take some pics soon of my rig, it's been a while.

Just a note -- if all you need is Midi-to-Trigger, you can build a Midibox CV with only a core board and a DOUT board, which would be extremely cheap with the available kits. Be sure to check out http://www.ucapps.de.

Skrog Productions · Posted: Mon Feb 16, 2009 10:44 am Post subject:

oops, i ordered the elby kit on saturday, never mind.
There's loads of cool stuff on that link, thanks Lars.

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

Great looking setup Skrog! And an M6R!! Droolfest to me! I especially loved the oscillator sync on it. Wonderful sound to it. I only ever recorded my M6r into 1 tune. I wish I used it in more of them. Alas ......

Creatorlars! Wait wait wait! Surprised

A couple of years ago, I had ordered everything that I needed to build the MIDIbox SEQ V2.0. I got about 75% of the way there (all PCBs done, but the panel only about 10% completed) before I decided to instead work on my own sequencer designs. (Success, a year later, with my Quadatrix 1V/o sequencers.)

NOW though - seeing the MIDI to CV kit and you've gone that route - could you clue me in on exactly which option that you chose and how well it's working??

I'm asking cuz, I'm currently using a Roland MPU-101 (4 channels). I bought Marc Bareille's MCV-876 (still to build) which will give me 4 more channels. My hopes though are having somewhere between 16 and 32 channels of MIDI to CV for all of my synth and drum requirements.

I was thinking of uploading the MIDI to CV code to my MIDIbox PIC, but I'm stuck so far on which of the MIDI to CV options to go for.

Curious to what you've done! Smile

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

creatorlars · Posted: Mon Feb 16, 2009 4:44 pm Post subject:

neandrewthal · Joined: May 11, 2007 Posts: 672 Location: Canada

I'm planning a 6U x 5U super dense(a la creatorlars) MOTM format drum synth to go in the corner of my modular, to be played with dual CGS pulse divider/logic combos, gated comparator, 4 channel gate sequencer and whatever other logic my modular can throw at it. So far, I've got 2x MPS, 2x SDS-3, CGS Cyncare, dual drum and dual chime to go in it, but there's no way I'll be able to fit it all help

For the output, I'm going to have an unattenuated output jack for each, and an 8 input mixer off to the side with the drum voices normalled to it through switching jacks. That way all the mixing is done in one place and I can still send all the voices through whatever external effects I want.

creatorlars · Posted: Mon Feb 16, 2009 5:05 pm Post subject:

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

neandrewthal · Joined: May 11, 2007 Posts: 672 Location: Canada

creatorlars · Posted: Mon Feb 23, 2009 7:55 pm Post subject:

Skrog Productions · Posted: Fri Mar 06, 2009 1:39 pm Post subject:

Hot tin/lead has been sizzling away at the workbench to make these for the project.

most important build ... power supply.

Used vero board for ease, a dual 12V & a dual 15V supply, had the reg's lying around so used em.

Boards populated so far.......

2X ds8 clone

2X MPS

1X Bass + +

8ch mixer with pan L-R & FX inserts & H-phones (Ray's simple st mixer).

Working on the panel this weekend.

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creatorlars · Posted: Fri Mar 06, 2009 1:45 pm Post subject:

Beautiful, great work!!

I'll upload some pics of my drum machine in progress (been too busy using it!)

Skrog Productions · Posted: Fri Mar 06, 2009 1:52 pm Post subject:

Steady.

. you could drive a bus under some of those resistors on my mixer vero board Ha Ha Ha.

Skrog Productions · Posted: Sat Mar 21, 2009 12:39 pm Post subject:

Hello folks.
I've been busy drilling and getting the front panel sticker sorted out.

hoping to start wiring this week coming.

Picture update on drum synth sound module so far........

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Sticker application

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Populating front panel & box painted black

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creatorlars · Posted: Sat Mar 21, 2009 12:44 pm Post subject:

Awesome!!! I have the first four modules in my big 808 rack panel, pics soon.