Building a new drum synth

Skrog Productions

Hi there.
Over the past few months, I have been keen to re-design my drum synth I built in 2009. I have had success with building the 808 hi hats / cymbal / cowbell from the great layouts by Minus , I also have soldered together the 808 kick & snare by Eric Archer and recently ordered some of the hex-inverter nein oh nein pcb's.
Once I have finished experimenting with all the mods, I can get the panel stickers finalised for the pot & switch layouts.
Also, in the new box , I will be re-panelling the voices from drum synth V1 (MPS / cynare / Bass++ / DS8).

Here are some pics of the 808 strip boards being hooked up for testing & populating the nein oh nein pcb's.......

808cymbal -cowbell-hi hats.jpg

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808kick - snare.jpg

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old bit of panel used for testing controls

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neinohnein.jpg

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Kick / Clap / Rimshot / & battery acid CV (still to construct)

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Skrog Productions · Posted: Mon Aug 25, 2014 11:19 am Post subject:

Control .......

I will be using a hardware midi sequencer to fire the drum sounds , this time I decided to try out the Engineers at work 24 output midi to trigger, this pre built smt board just needs the choice of soldering the wires direct to the board or to fit headers / connectors , I decided to fit screw terminals ( easy for testing modules). Using the dip switch you can select midi channel / trigger length (1ms or 10ms).
I did have a good look at the similar one from highly liquid but they are in the process of designing a new unit with usb socket for updating.

Here is a pic of the trigger unit wired up to test the 808 stripboards....

midi to trigger.jpg

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Skrog Productions · Posted: Sat Aug 30, 2014 3:48 am Post subject:

Hi

Been soldering after work this week , now got the control wires onto the neinohnein kick clap & rimshot . I had a quick look on the hex-inverter site last night, and the snare pcb is back in stock, yay! , so I had to order one Very Happy

.

If the weather stays dry today , i'am intending to assemble my plywood double row case for the drum modules , I managed to retrieve some nice off cuts of clean Latvian plywood being used on a new hospital construction site I was working at Smile

.

More pics and reports as the project goes on......

Dave.

hex-inverter pcbs wired.jpg

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Paradigm X · Posted: Sun Aug 31, 2014 1:00 pm Post subject:

nice

i do enjoy these build threads. i want to build a similar box.

nice one, Ben

Skrog Productions · Posted: Mon Sep 01, 2014 12:56 pm Post subject:

Hi Ben , Thanks Smile

.

My first few home made boxes turned out a slight parallelogram shape (a bit of box twisting needed to get the panel sitting straight) but i'am getting a bit better at woodwork now Very Happy

and have learned to use a strip of wood as an angle brace to keep the box internal corners all at 90deg square.

Dave.

Skrog Productions · Posted: Mon Sep 01, 2014 1:13 pm Post subject:

panel plates.........

I asked a friend nicely, who works at an engineers/metal workshop , to slice me some 3mm aluminium plates for the drum panels, on the big hydraulic cutter .
In the UK, I have noticed a few ebay stores that cut aluminium sheet to order, handy if you don't have an engineering friend.

A pic of the plates laid out to show upper row & lower row, 800mm worth long and both rows are 140mm high.
The 100mm by 140mm panels are for the 808 & 909 & cynare & DS8 & Bass++ drums.
The 150mm by 140mm panels are for the Mega Perc. Synth.
And the 200mm piece is for cv-Pan / battery acid-distortion+compressor / LFO's & some mixing.

Dave.

bare panels.jpg

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Skrog Productions · Posted: Sat Sep 06, 2014 4:39 am Post subject:

Hullo

.

more progress ....
I have been sawing & tacking some plywood together to make the new box for the new and updated drum modules, I am building.

Got 3 coats of dark grey paint slapped on the box and have screwed the 4 rubber feet onto the base of the box.
The bit of vertical wood inside the box is a support strut to keep the plywood from "bowing" while it was sitting in the garden shed, it is currently maintaining 282mm top to bottom height, the length of the box, it will be taken out when the modules are ready to fit.
Also a pic of the bare alum plates sitting in place, the box seems relatively square, no alum over shooting the fix rails , hurrah Very Happy

.

Next jobs ... transplant power supply from old drum synth into new box / make a 9V power circuit for the midi to 24 trigger unit / mod the old voices & plan out FX & mixer areas. Smile

Dave.

new drum synth box.jpg

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new box & panels.jpg

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Skrog Productions · Posted: Tue Sep 09, 2014 11:49 am Post subject:

Hullo .

Horror ... I removed the back panel from drumsynth vers 1 (2009) to remove the power supply thinking an easy job , and I discovered I had installed a 30VA toroidal transformer (almost just enough for that drum synth).
Of course I am now nearly doubling the load with 2 rows of modules, but , after a rake about in one of many electronics boxes in my cupboard, I found a new 100VA toroidal (dual secondary), magic Very Happy

.

I sat down at the desk with a pen & paper and totalled up my expected current use for + line and - line on this new diy drum synth.
Allowing a bit of head room for expansion ( I've designed this drum synth to have a few blank panels for future)

+ line 700mA.
- line 620mA.

Total 1.32 Amps .
The new transformer is a dual 15V / 0V , 100VA toroidal which gives 3.333A max ( that has worked out nice because I always like to have a transformer working at half load or less, also called de-rating).

I will be using a similar design to the big power supply I built for the blue modular system, Raw DC supply distributed with thick wire to several regulator / buss bars.

Below is a pic of the new transformer with a bag of mounting rubber pads & cap plates & bolts ,
the 2nd pic is the Raw DC board which takes the transformer output and rectifies it and smooths it , 4 sets of 3way terminals,will distribute the expected +18V / 0V / -18V Raw DC through thick cable to the regulator busbars , one unfinished one is pictured (the regulators get wired to this board with the green module power connectors)

Dave.

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Skrog Productions · Posted: Sun Sep 14, 2014 10:55 am Post subject:

Hi Again.

Had a chance this weekend to work on the power supply.
Finished the little regulator / distro boards and bolted the regulators onto the alum L bar, using a thin scrape of heat paste & mica insulator plates & bushes. The wiring between the Raw DC board & the regulators is 1.5mmSq(csa) 3 core 16Amp flex , same size wire used for connecting the regulators off the board.
The L bar is distanced fixed using 12mm hex nuts as spacers.
From left to right there is 2 sets of dual 15V distros (6 sockets each) / the Raw DC board & the dual 12V distro (5 sockets) , which also has a 78L09 circuit (+9V) for the wee midi to trigger module.

Still to put a safe enclosure round the 240V connections to the transformer primary leads , probably a little choc box type mains connector & a rubber shroud over the IEC rear.

Busy populating the nein oh nein snare pcb now , more pics through the week.

Dave. Smile

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Skrog Productions · Posted: Mon Sep 15, 2014 10:29 am Post subject:

Hi

Finished populating the Hexinverter snare pcb , ready to wire it now, once it is powered up with a testing panel, I want to study the noise VCA section and work out where to change a resistor for a pot & limit resistor, to give a bit of decay control.
Next to do, is build the mods for the Bass++ on breadboard & try each before finishing the panel layout design.

I have been absolutely gagging to get the panels & control legend stickers done, but previous experience is telling me to leave them till last so I can be certain I have the panel layout worked out Smile

.

Dave.

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PHOBoS · Posted: Mon Sep 15, 2014 11:07 am Post subject:

looking great sofar Dave thumleft

Skrog Productions · Posted: Mon Sep 15, 2014 12:04 pm Post subject:

Thanks Phobos

isak · Posted: Tue Sep 16, 2014 7:50 am Post subject:

Indeed, that really looks great Smile

Will be interesting to see if you'll make the panel blue Shocked

Skrog Productions · Posted: Fri Sep 19, 2014 10:58 am Post subject:

Thanks Isak Smile

The colour scheme for this drum synth is close to the old drum synth, a sort of corn field yellow colour for the sticky back vinyl which will have the legends printed in black.

Old drum synth ...... http://electro-music.com/forum/topic-34152-0.html&postdays=0&postorder=asc&highlight=

Dave.

Skrog Productions · Posted: Sun Sep 28, 2014 6:39 am Post subject:

Hi

I've been working on the quad bass++ , populating & deciding on mods to add.
Apologies to Bill (state-machine) from Long island, when you sent me the quad board in 2010 you didn't want to see the board in a drawer for 4 years Embarassed

, well the time & project is right for it now Smile

.

Left off R24 / C2 / C7 on each of the 4 voices for the wave mod , bump & pip mods & pitch cap increase mod , which I will solder all the mods on a strip of veroboard to bolt on.

I have done a test layout of the panel , instead of putting the quad bass++ across 2 100mm panels, I have robbed the 200mm long bit I was keeping for the mixer area, as usual it's a tight fit , but I think I've got all the controls I need for bass/tomtom sounds I need Smile

.

Dave.

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Skrog Productions · Posted: Fri Oct 10, 2014 11:40 am Post subject:

Hi again , been in design mode after work for a few weeks Smile

Still work in progress , here is the first test mock up layout of the drum panels with one spare panel for future at the top right.

Still to finish labelling on the 808 & 909 voices.

All the voices go to the pan control panel , which is the 20 channel mixer which will have trimmers on the veroboard for setting a balance of levels.

The MPS / Bass++ & Cynare panels didn't have room for output sockets ( to be used as send to FX outs) ... so I have included a couple of rotary switches & respective out socket for sending a voice from those modules to an fx.

The 5 mixer inputs , at the lower right , can be used for external modules or as FX returns into the stereo bus.

Hope to get the mixer built over the weekend Smile

Dave.

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Skrog Productions · Posted: Sun Oct 12, 2014 3:42 am Post subject:

Almost finalised yellow layout of the front panels , adjusted some text & fixing points & spelling & fixing nut over text fowls , should have it ready to print off next weekend , then weeks of assembly after that Wink

.

Dave.

final panels yellow.pdf

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Skrog Productions · Posted: Sun Nov 16, 2014 2:13 pm Post subject:

Hi all , been busy Smile

Stickers done , fixed on and all panels drilled , started the first build ... the pan controls & the mixer & FX panels , all working good apart from 2 pots wired wrong direction Smile

fixed now , mounted the midi to trigger pcb in the case and fitted the midi in , din socket round the back of the case , the pcb is powered from it's own 9v supply off the 12V board inside the case .

First drum module finished this weekend, Hexinverter rim shot & clap on one module plate , works great first power up ( all the drum circuits are powered 15V -- FX & mixer are 12V).

I made a mistake on the rim shot panel front , overdrive control pot , I forgot to delete that one when lining up the pots on the design programme , so... Smile

I had a stab about with a 20k pot and found R22 (22K) had a resonance sounding change , popped out R22 and replaced with a 20K pot and a 100 ohm limit resistor in series , cool , no blank control now Very Happy

More updates as I work through the drums....

Dave.

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Pan & Mixer FX.jpg

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Skrog Productions · Posted: Sun Nov 23, 2014 8:00 am Post subject:

Hi again

Not had much time through the week , but got another module finished this weekend.
Hexinverter 909 kick & snare drums worked first switch on , Fab Smile

, while they were powered up I had a little tweek with the kick tune control to make the tuning go a little lower(used a 1M pot) and also increased the noise decay time on the snare (increased C12 to 680N & changed R3 to a 100K trimmer) .

Next to start is the eric archer & minus 808 stripboards , Smile

Dave.

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Skrog Productions · Posted: Mon Nov 24, 2014 11:04 am Post subject:

Hi

After a quick question in chat room yesterday , I decided to whip up a quick veroboard circuit with 24 non inverting unity buffers for each 5V trigger output of the midi to trigger unit.
I was experiencing some problems on a few trigger outs when testing the first 2 modules , after a bit of breadboard testing set up, a simple op amp buffer cured the mis-triggering.

Dave.

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Skrog Productions · Posted: Sat Nov 29, 2014 11:50 am Post subject:

Hi

Been soldering again, I have got the 808 kick and Snare transferred from a test panel to the final panel , a couple of wrong direction pots I need to swap the wires round on and then adjust a trimmer for the noise level .

next module to work on will be the EM thread by Minus - stripboard hihats / cymbal/ cowbell.

Dave.

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Skrog Productions · Posted: Sun Dec 07, 2014 1:55 pm Post subject:

Hi

Been busy with the soldering iron , got the stripboard high hats / cymbal & coo bell bolted to the panel & wired up , all working well, Smile

.

Next to work on will be the 2 Cynare modules.

Dave.

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isak · Posted: Mon Dec 08, 2014 10:15 pm Post subject:

Hi Dave.

Looks good man!
Keep up the good work Smile

Skrog Productions · Posted: Sun Dec 14, 2014 2:25 pm Post subject:

Thanks Isak , taking time to build , though it sounds great so far.

Dave.

Skrog Productions · Posted: Sun Dec 14, 2014 2:27 pm Post subject:

more soldering action Smile

....

Finished re-panelling the 2 CGS cynare modules , slowly filling up the box Smile

.

Dave.

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