DIY Synth

zur deutschen Version

user's manual: DIY_Synth_Manual.pdf

DIY project in the German magazine
KEYBOARDS
self-made analog synthesizer based on the DIY Synth kit
(with sound examples)

Customer Application Examples

 

Customer Examples on Youtube:

http://www.youtube.com/watch?v=C0Xx6e3qMfQ&feature=related 
http://www.youtube.com/watch?v=C0Xx6e3qMfQ  
http://www.youtube.com/watch?v=agSpQyhnHJg&feature=related
  
http://www.youtube.com/watch?v=6j5DQzHVU24&feature=related
 

http://www.youtube.com/watch?v=GOa0aZAWjGs

If you built a synthesizer based on our DIY Synth board(s) please send us pictures of your final assembly to hardware@doepfer.de. Provided that we publish your pictures on our website we offer 50% special discount for the planned expansion board (will probably include a noise generator, S&H, ring modulator, midi/CV interface, random voltage and some more). If you can't wait until then you may even purchase a second DIY board with 50% special discount. Pay attention that you have to order these boards from us directly. It is not possible to process these orders via our dealers or representatives.

Pictures and videos from the DIY Synth workshop in Berlin at SchneidersBuero:
http://blog.emusician.com/robairreport/2010/03/25/doepfer-cookbook

 http://emusician.com/videos/interviews/doepfer_at_schneidersladen/


Important note: The DIY Synth kit is planned for experienced users only who are familiar with both electronics and analog synthesizers. It is definitely unsuitable for beginners ! For example we will not be able to offer the service to repair a customers assembly if it does not work as it should, or to make individual suggestions how to wire the board for special applications. We have to emphasize this fact very clearly in advance to avoid unsatisfied customers who will have problems getting their synth to run. Of course we will publish a detailed list that explains the function of each pin and a suggestion how to use this pin.

The DIY synth is the beginning of a a new product line: a low cost DIY kit to build a full-fledged analog synthesizer. The kit is made of an assembled and tested pc board that includes all that is necessary to build a standard analog synthesizer: 

VCO:

  • Sawtooth output
  • Rectangle output (with variable pulse width)
  • Four frequency CV inputs (1V/octave with tempco option)
  • Frequency CV summing input (can be used to increase the number of CV inputs if more than four frequency CV inputs are required)
  • Two PW/PWM CV inputs
  • PW CV summing input (can be used to increase the number of CV inputs if more than two PW CV inputs are required)
  • Linear FM input
  • Hard sync input

VCF:

  • Multimode filter
  • lowpass, highpass and bandpass output (optional low-notch-highpass with external potentiometer)
  • 12dB/oct
  • Two frequency CV inputs (one roughly 1V/octave, one roughly 0.5V/octave)
  • Frequency CV summing input (can be used to increase the number of CV inputs if more than two frequency CV inputs are required)
  • Audio input
  • Audio summing input (can be used if more than one audio input is required)
  • Overdrive/distortion possible
  • Manual resonance control
  • Resonance up to self oscillation

VCA:

  • Exponential control scale
  • One CV input
  • CV summing input (can be used  if more than one CV input is required)
  • Two audio inputs
  • Audio summing input (can be used if more than two audio inputs are required)
  • Overdrive/distortion possible
  • Audio output

ADSR:

  • Connection for attack, decay, sustain and release controls
  • Connection for range switch (3 ranges)
  • Connection for LED display  
  • Gate Input
  • ADSR output

LFO:

  • Connection for frequency control
  • Connection for range switch (3 ranges)
  • Connection for LED display
  • Triangle and rectangle outputs

Slew Limiter:

  • Connection for slew control
  • Input
  • Output

Inverter

  • Input  
  • Summing input (can be used to increase the number of inputs, e.g. to built an inverting mixer)
  • Output  

Remark: The summing inputs (VCO frequency CV sum, VCO PW CV sum, VCF frequency CV sum, VCF audio sum, VCA CV sum, VCA audio sum) can be used to increase the number of CV or audio inputs if the available number of inputs is not sufficient. The additional inputs have to be connected to the sum input in question via serial resistors. The value of the resistor in question defines the sensitivity of the corresponding CV or audio input. Additionally required resistors are not included with the kit !

DIY Synth pc board with tempco option
measures: ~ 201 length x 38 width x 20 height, measures in mm
click to the picture for a higher resolution
that's what the customer gets !

The kit is planned for customers who are familiar with electronic basics as the kit does not include the controls, switches, sockets, power supply and the case. These elements have to be added and wired by the customer. The board is equipped with dual row pin headers. This enables the usage of dual row female connectors instead of soldering the controls directly to the pins. The customer can choose the desired size, shape, type and color of these elements (e.g. rotary potentiometers or faders, small 3.5 mm jack sockets or ľ" sockets or banana type,  small or large knobs and switches and so on). Even the type of wiring is free: the range goes from a pre-wired standard synth (VCO-VCF-VCA type) up to a fully patchable modular system. Two or more of the kits can be combined to obtain more VCOs, ADSRs, LFOs, VCAs or VCFs, e.g. to built a more complex pre-wired or modular synth. A stabilized symmetrical 12V power supply (i.e. -12V, GND, +12V)  with at least 150 mA current is required.

We also think about a DIY expansion board that may contain a noise generator, S&H, ring modulator, mixer, maybe a Midi/USB interface and other often used synthesizer units. But so far there is no release date, price and features for the expansion board available. 

The additional working time and required skills to build a working unit from the kit should not be underrated !  One should count at least on one weekend, even if you are an experienced hobbyist. To obtain all features about 25 potentiometers, 20 sockets and several switches have to be mounted into a suitable housing and wired faultless. We ask for your understanding that we cannot offer the service to troubleshoot a customerís assembly. The pc boards comes assembled and tested. Only the adjustment of the 1V/octave scale and the frequency offset of the VCO have to be carried out by the customer.

We do not offer complete units but only the assembled and tested pc board ! The pictures show application examples for the DIY synth board. Assemblies like these are not available from us !

We also do not offer kits with unassembled pc boards (i.e. kits that include the electronic parts and the unassembled pc board and the customer has to assemble and solder the parts). We made some bad experiences in the past with such kits. Some customers were very angry when they had to pay for the repair of a non-working assembly and the total charges were higher than the ready assembled and tested unit (sometimes we even had to refuse the repair of totally improperly assembled boards because the estimated repair charges exceeded the price of a the assembled and tested pc board). That's why we will definitely no more offer such kits !

Prices:
Euro 100.00 (without controls, sockets, switches, cables, power supply and case, without temperature control of the VCO)
Euro 120.00 (same as above, but with temperature control of the VCO)

Cable set (two ribbon cables with 16 pins and five with 10 pins, each ~ 50 cm long, with assembled dual row female connectors on one side, the other side of each cable is open, enables to connect/disconnect the DIY board without any soldering from the customers assembly) 
Euro 20.00

Tempo option separately (for later upgrade of a DIY Synth board without tempco): Euro 30.00

Cable set remarks:
Standard dual row female connectors (IDC with 1/10" = 2.54 mm pitch) with 10 and 16 pins are used, experienced users will have no problems to assemble these cables themselves.

DIY SYNTH cable set
(click to enlarge)

Remarks concerning the temperature compensation (tempco):
The version without temperature compensation (tempco) is fine for experimental sounds or drum/percussion applications where the exact 1V/oct scale of the VCO is not essential. For applications where the synth is played by a CV keyboard or Midi/CV interface the version with temperature control is recommended. This version has a good 1V/octave tracking over about 6-7 octaves in the range 40Hz ... 5kHz after ~ 20 minutes heating period.
 

Power Supply remarks:
A stabilized symmetrical 12V power supply (i.e. -12V, GND, +12V)  with at least 150 mA current is required. As the VCO tuning is affected by the stability of the power supply a good stabilized supply is essential.
If the version with temperature compensation (tempco) is used a +/-12V supply is essential. The tempco does not work with +/-15V supplies ! For versions without tempco even +/-15V supplies can be used. If no suitable power supply is at hand each A-100 power supply can be used, e.g. the A-100 miniature power supply (A-100MNT), the A-100 standard power supply (A-100PSU2) or the supply used in A-100 DIY kit #1. A-100PSU2 should be used only by really experienced users as it has to be wired to 115/230V mains voltage.

Parts list (suggestion):
Here you find a suggestion for the parts required for a typical application: DIY_SYNTH_bom.pdf


Pictures of the application example shown at NAMM 2010:
Such ready made assemblies are not available from us, but only the pc board !
In the pictures a tool box suitcase from the hardware store and an acrylic glass front panel is used.

yes we know: one of the labels should read "SUSTAIN" instead of "SUSTIN" :-)


Schematics of the pc board


Schematics of a typical application example