Within DAW's you are usually able to create macro control knobs. This is something you might want to do for modular synths as well. Maybe you'd like to control the cutoff frequency and resonance at the same time. Well now you can.
For this instructable I have created a module that gives you control over 3 CV outputs ranging from 0V to 5V.
ATTENTION, I am not liable in any way for damage to your modular synth. In Dutch we say: "Meten is weten" ("measuring is knowing"). It will probably not be necessary but I HIGHLY recommend you use a voltage meter when you connect outputs of DIY's to one of your other modules.
What you will need:
- Solder iron
- Solder tin
- Conductive wire
- Panel (I created one from plexiglass, 2 or 2,5 mm)
- Drill with 3M and 6M bit
- A cutting knife
- A perfboard
- A couple of sockets (I used 3 from thonk: https://www.thonk.co.uk/shop/3-5mm-jacks/)
- A electrolytic cap (I used 100uF because I had it lying around but 10uF will also be fine, just make sure it is above 12V)
- Two ceramic caps (100nF)
- A 5v voltage regulator (7805 IC)
- Three 10k potentiometers (other values are also okay)
- A couple of male headers
- A cable to connect your module to the bus of your case
- A bunch of wires to solder
- A wire cutter
- 3 Knobs to make it look nice (mine are Rean Flexi-fit knobs)
Step 1: Prepare Your Components
If you haven't worked with electronics often I would recommend building the circuit on a breadboard first. Just so you know how it's built.
- Take a piece of perfboard and cut it to the right size (if you use a cutting knife, you can slice a couple of times and then break the perfboard). I cut it to the size of 6 HP, which is 1,2 inch or 30,48 mm (1HP is equal to 0,2 inch). More info on this here: http://www.doepfer.de/a100_man/a100m_e.htm
- Place the potentiometers centred and in a way so they have some space in between them. Place the socket facing the same direction.
Step 2: Solder the Components
You do not need to place the components like I did. But you can use the pictures to get an indication of how to place components.
- Solder the potentiometers and sockets
- Take the male headers (which should be 2x5) and place them somewhere between the pots. Preferably shifting them to left or right (and facing the rear end of the perfboard). Solder them...
Remember that the header is the same as the drawn picture above (so +12V will be the upper pin, then GND 3 times, then -12V). For this instructable we will use one +12V and one GND.
- Now solder the electrolytic cap with the + side (longer pin) to +12V and - side (shorter pin or with grey indicator) to GND as close as possible to the header. This cap will stabilise the current coming from your bus.
- Solder the 5V voltage regulator where there is room (see picture). When you are facing the voltage regulator the left pin is the input (+12V), the middle is GND and the right is the output (+5V).
- Now place the ceramic caps near the voltage regulator (see picture). And solder them.
- Solder the pins of the ceramic caps to the pins of the voltage regulator. Of each ceramic cap there should be a connection to GND. Of one cap a connection to the input of the voltage regulator, and of the other cap a connection to the output of the voltage regulator. (See the schematic, just make sure you do this correctly!!!)
- Now connect all the GND pins of the components. Remember that the potentiometer pin you connect to GND will be the side of 0V. So preferably left pin when facing front end, right pin when facing rear end. (See pictures).
- Now connect all of the middle pins of the potentiometers to their corresponding sockets. You can put a 100R resistor in between, this is not necessary but is recommended.
- Now connect the +12V pin of the header to the input pin of the voltage regulator.
- And finally connect the output pin of the voltage regulator to each of the potentiometers.
Check everything once more before you connect it to your case, make sure you've soldered everything correctly. Connect it to your case, and check if the output of each socket ranges from 0V to 5V with a voltage meter.
That's it! Have fun controlling stuff! You can use this module together with a passive multiple for example to split the signal to multiple parameters.
Be sure to check out our fabricated modules here: www.livestockelectronics.com
And our other instructables here: https://www.instructables.com/member/LiveStock+Ele...