Not everybody needs an 808
Some time ago i started a DIY handclap project. The design was not based on Roland TR808, but Boss HC-2 (or Amdek HCK-100, if you like). With some problems I completed the prototype and made an eurorack module – it works really well.
The circuit
Boss circuit is different from Rolands. It uses CMOS based digital noise source (only 2 states at output – 0V or ~4,5V), which gives possibilities for some modification. As opposed to 808, this device has more sound sculpting options, more then just “level” control – 4 knobs in total to tweak and lick. I’ve tried many mods, but only 3 last as “fun and usable”. For such a simple sound, PCB is quite complex. The final schematics HQ pdf used in this project can be found here. The topolgy of the circuit is very simple – one digital noise generator (CMOS ICs based), one EG (generates burst of pulses) and one VCA (BA6110 based).
![DIY Handclapper PCB in a cartoon box](https://syntherjack.net/wp-content/uploads/2017/01/vegeta-handclap-proto-closed-syntherjack.jpg)
Prototyping & euroracking
First, I prototyped the circuit on self-etched PCB (I don’t like to make complex analog projects on breadboards) in a beautiful cartoon box, leftover from SDSV drum synth project. I made an small error in BA6110 connection, so I had to put an additinal small PCB with transistor converter (original circuit uses BA622, I have forgotten about it).
![DIY handclapper - prototype](https://syntherjack.net/wp-content/uploads/2017/01/vegeta-handclap-proto-opened-syntherjack.jpg)
After tests, I moved to final , professionally manufactured PCB (I made only one small error in prototype) and put in into 8HP eurorack module. The front panel doesn’t look as good as it should – I used acetone for aluminum cleaning, which caused the water decal to peel off. Now I use simple soap, works so much better. The full description of the water decal method can be found here.
![Euroracked HC2 handclap top shot](https://syntherjack.net/wp-content/uploads/2017/01/HC2-top-syntherjack.jpg)
The trigger indication LED PCB (the small green one) is mounted in somehow silly way – sticked with a two-sided adhesive tape to a back of the pot. But you can still remove it without problem, in opposite to hot gluing *.
*it was a bad idea, has fallen in 2 years, had to glue it anyway :/ (added 8.03.2018)
![HC2 eurorack module, side shot](https://syntherjack.net/wp-content/uploads/2017/01/HC2-back-syntherjack.jpg)
The front panel is simple and every knob makes a difference to a sound. All pots are Alpha Taiwan 16mm with dust cover – very cost effective in synth DIY and much better then no-name asian devices. The CLOCK control is my favourite one – can make the clap sound really FAT!
Full data
Controls:
- HALL (“fake reverb” level),
- DRY (noise source output filter cutoff),
- BURST (pulses count in envelope),
- CLOCK (noise source clock speed),
- LEVEL (output level).
Inputs / outputs:
- TRIGGER (trigger pulse input),
- OUTPUT (handclap output),
- NOISE (noise output),
- LED (indicates trigger).
Mechanical:
- PCB size: 80×100 mm,
- module front panel size – 8HP (~41×129 mm).
Power consumption – maximum (only positive rail) :
- 0 mA @ -12V, 20mA @ +12V,
- 0 mA @ -15V, 15mA @ +15V.
And now, all you are waiting for, a demo! (I find handclap demos very boring by definition, but this one crossed the limits ).
A more complex approach to handclap synthesis was used in my SnapClap project, check it out!
Cheers
Jack
The ‘here’-link to your schematics seems inactive. Would be nice to see you fixing that. : )
Cheers from Germany! Nice blog : )
Thanks for the info, link fixed!
Great projects, any chance of sharing the pcb mask?
Keep up the good work.
Thanks
I second the pcb layout, that would be ?
Every once in a while it makes a kind of bark or squeak sound. You can hear it the most at 2:04-2:06 in the video.
What’s that all about!?