Hive Mind Synthesis

SodaPressed

BOM

Resistors

7 - 4k7

3 - 10k

3 - 100k

1 - 200k

1 - 2M2

1 - 1k

1 - 1M

1 - 2.2k

1 - 150

1 - 110k

1 - 100r

Diodes

2 - 1N4148

1 - 1N5819

1 - Ferrite Bead

Capacitors

Ceramic Disc

2 - 1uf

2 - 27nf

2 - 10uf

1 - 0.1uf

1 - 1nf

1 - 10p
Radial

1 - 10uf

1 - 4.7uf

1 - 1uf

Six Faceplates from which to choose!

Transistors

1 - 2N3904 - a noisy one. We use this one

5 - 2N3904 - any old one will do

ICs

1x DIP8 ICM7555xP
1x DP8 Socket

Potentiometers

1 - 100k Trimpot (Bourns Horizontal)
1 - 10k Alpha 9mm
2 - 50k Alpha 9mm

Jacks, Headers, etc

1 - 10-pin IDC Eurorack Power Header

2 - Thonk-style QingPu jack

BUILD

As is tradition, it's best to work your way up from the shortest components to the taller ones. Everything should be marked on the BOM sheet to make this as quick as possible

1) Resistors, diodes, bead

Lots of resistors! Polarity for these doesn't matter.
Be sure to check polarity on the diodes - the non-striped end goes to the "A"

Install the ferrite Bead at this step as well - no polarity to worry about here.

2) Small Caps, IC Socket

It's here that we add the smaller disc capacitors (no polarity) and the socket for the 555 timer. make sure the chip socket's notch matches the silkcscreen on the board!

3) Other Caps

Install the electrolytic caps, being sure to pay attention to polarity. The negative end (the one with the white stripe) aligns with the white side of the circle on the board.

4) Transistors

Q1 is a "special" transistor. What makes it special? I really don't know, but some other transistors with the same specs don't seem to work here. This transistor actually generates the noise. Be sure to watch your polarity here - the center leg should go out towards the rounded edge of the transistor and match the shape of the silkscreen on the board

5) Power header, trimmer
Solder the power socket into place, once again keeping an eye on polarity - the notch on the silkscreen should match the notch on the socket.
Add the trimmer resistor. Our footprint is a lil off so it may sit crooked. You can bend the pins to make it sit flat if you want, but you don't have to.

6) Jacks, Pots

Flip the board over and add the jacks and pots, making sure to place the 10k pot at "Tone" and the other two at "Attack" and "Decay" - DON'T SOLDER THESE YET!

Add the faceplate, then flip it over, assuring all of these new parts are properly positioned.

You can then solder everything into place, add nuts and knobs (I only add a nut on the jacks and the top pot).
Install the nuts on the jack first, then the pot(s), making sure not to bend the faceplate by overtightening.

Turn all of the shafts all of the way counterclockwise and add the microknobs, making sure to align the dot with about the 5 o'clock position. Lastly, add the 555 Timer chip to the socket, paying attention to polarity. The dot on the chip should be on the same side as the notch in the socket, which should match the printing on the board.

Plug in the power cable but don't mount it into your rack yet - time to adjust the noise!

USE

Before installing into your rack, you'll want to adjust the noise like this:
Power the module and run the output somewhere so that you can hear it
Run some sort of trigger/sequence to the PRESS so that the module is repeatedly triggered and you can hear it, adjusting the rise and fall so that you can hear a longer hit.
Adjust the trimpot to clean up or distort the noise. When I calibrate the factory builds, I turn the tone knob all the way down, then up a notch, then adjust the trimpot to give me clear noise at that level. That way if I turn the tone all of the way down I still get that CRONCH..
Once you have the noise where you like it, install in your rack and get SODApressed!
Attack and decay adjust attack and decay rate of envelope.
Tone adjusts - you guessed it - Tone.
Trigger runs into "press"
Audio runs out of "Out"

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