Synth Project: Overview

[For the full project details go to the Saund-Box Project Page.]

For my Holiday project I am going to build a low budget modular analog synthesizer as I explain in an earlier post. Here I thought I would spec out exactly what the project entails and the steps involved.

In a nut shell I will be building the full version of the Synth-DIY Experimenter Board (SEB) designed by Ray Wilson of Music From Outer Space (MFOS), but I will be adding the Micro-sample & Hold Module, as well as the “kludge” modifications suggested by Ray himself, and powering the unit with the MFOS Wall Wart Power Supply.

I also want my kids to be able to play with the synth so I’m going to add an internal speaker using the amp circuit from the Noise Toaster project as well as a headphone jack so they don’t have to hook the board up to an amplifier to use it.

Definitely a challenge for me as most of the projects on MFOS, including this one, only provide a PCB board for the build – everything else has to be sourced and built by the user and, as you will see, that can add up to a bit of work.

Ray does provide a front panel template and art for SEB:


with accompanying wiring diagram:

complete panel wiring with reversed legends small

Which would save a lot of time and effort if it wasn’t for the fact that I’m adding the Sample & Hold module and kludge options and want to fit them all onto one panel, preferably of legal page size (8.5″ x 14″) or less so it is easier to print.

So the steps involved in completing the project go something like this:

  1. Purchase the PCB boards for SEB and the sample & hold module.
  2. Purchase the wall wart power supply kit (which actually has everything included so that is easy at least)
  3. Source and purchase all the electronic components and hardware
  4. Source and purchase aluminum sheet for the front panel
  5. Design front panel layout, create template and final art
  6. Create wiring diagram for panel components
  7. Build the power supply
  8. Solder in all PCB components for SEB and the Sample & Hold board.
  9. Create the front panel. Mount the panel components and boards. Wire it all up
  10. Build an enclosure
  11. Add the power supply and mount the front panel to the enclosure
  12. Power up and have fun….hopefully

I’ve already completed the first five parts, though I still have some components left to purchase.

The creation of the panel layout was a major effort and I will dedicate a whole post on how I went about doing that using Inkscape. In the meantime here is a tease of what the panel will look like:

EB Panel

I’m very happy with the layout. Managed to make it all fit within an 8.5″ x 14″ area, although I’m only allowing for 3/8″ around the edge of the panel for mounting to the enclosure.

For the enclosure I’m lucky enough to have a friend who is very good at wood work and has the tools to boot. I’ve used SketchUp to design a simple enclose box using 3/4″ fir wood. Here is a render of the front:

SB Cabinet

And from the rear with the back panel removed:

SB Cabinet Back

And finally I though I would show the master component list I compiled from the SEB, Sample & Hold and kludge BOMs from MFOS. It’s quite a bit of stuff:

Quantity Item Value
1 CD4013 Dual D Flip Flop   CD4013  
1 LM13700 Dual gm OpAmp or sub   LM13700, LM13600 or NJM13600  
1 LM3900 Quad Norton Op Amp   LM3900  
6 TL074 Quad Op Amp   TL074  
1 LF444 Quad Op Amp   LF444  
1 2N5457 N Channel JFET   2N5457  
5 2N3904   2N3904  
2 PN4391 NFET   PN4391  
13 1N914 Sw. Diode   1N914  
2 General Purpose Green LED   LED  Gree
1 General Purpose Red LED   LED  Red
5 Potentiometer Audio Taper   1M  
7 Audio Taper Potentiometers   100K  
16 Potentiometer Linear Taper   100K  
3 Potentiometer Linear Taper   1M  
4 Resistor 1/4 Watt 5%   470 Ohms  
4 Resistor 1/4 Watt 5%   470K  
6 Resistor 1/4 Watt 5%   47K  
3 Resistor 1/4 Watt 5%   560K  
2 Resistor 1/4 Watt 5%   6.2K  
2 Resistor 1/4 Watt 5%   62K  
2 Resistor 1/4 Watt 5%   7.5K  
1 Resistor 1/4 Watt 5%   75K  
4 Resistor 1/4 Watt 5%   1.5M  
2 Resistor 1/4 Watt 5%   100 Ohms  
49 Resistor 1/4 Watt 5%   100K  
12 Resistor 1/4 Watt 5%   10K  
2 Resistor 1/4 Watt 5%   10M  
3 Resistor 1/4 Watt 5%   150K  
8 Resistor 1/4 Watt 5%   15K  
12 Resistor 1/4 Watt 5%   1K  
2 Resistor 1/4 Watt 5%   1M  
7 Resistor 1/4 Watt 5%   200K  
9 Resistor 1/4 Watt 5%   20K  
6 Resistor 1/4 Watt 5%   270K  
1 Resistor 1/4 Watt 5%   220 ohm  
2 Resistor 1/4 Watt 5%   2K  
2 Resistor 1/4 Watt 5%   30K  
6 Resistor 1/4 Watt 5%   3K  
2 Resistor 1/4 Watt 5%   3M  
5 Resistor 1/4 Watt 5%   4.7K  
3 Trim Pot   10K  
2 Alum. Electrolytic Capacitor 10uF  
2 Alum. Electrolytic Capacitor  22uF  
11 Capacitor Alum. Nonpolarized   1uF  
1 Capacitor Ceramic   .001uF  
4 Capacitor Ceramic   .01uF  
26 Capacitor Ceramic   .1uF  
2 Capacitor Ceramic   .22uF  
2 Capacitor Ceramic   22pF  
6 Capacitor Ceramic   .0022uF  
2 Capacitor Ceramic   47pF  
2 Tantalum Capacitor   4.7uF  
1 Capacitor Polystyrene Radial Leads   .005uF  
4 SPST Switch   SPST  
3 Switch SPDT   SPDT  
2 Switch SPST N.O. Push Button   SPST  
1 Switch DPDT   DPDT  
54 Banana Jacks      27 Yellow – 27 Blue
31 Potentiometer Knobs   9 Blue – 7 Green – 6 Yellow – 9 Red
1 Jack 1/4″ 2 Terminal     

When I complete the build I’ll create a final list of parts used and cost too. I already have major sticker shock but I’m having a lot of fun with the project so it’s all good.


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