555 Resonator Build Notes - NLC (NonLinearCircuits)

This is one of my favourite NLC circuits.
It's very versatile. It can be used as a filter, a VCO, a voltage controlled noise source and a voltage controlled drone module.

The module will oscillate without input (depending on the pot settings).
I like inputting a signal from a VCO which will trigger each 555 IC to create pulses.
These pulses can be manipulated with CV to create complex waveforms.

Andrew's manual for the 555 can be found here:
http://www.sdiy.org/pinky/data/FILTER%20panel%20manual.pdf
And his official build notes are here:
http://www.sdiy.org/pinky/data/Its%20555%20build%20notes.pdf

I have a version of this module in Serge/Banana format.


This build however is for a Eurorack Format module.
First, some pics of the virgin panel & PCB before we begin.


The module takes it's name from the 555 timer IC. This integrated circuit is used in a variety of timer, pulse generation, and oscillator applications. It's a very common IC and is cheap as chips.
The standard 555 package includes 25 transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package (DIP-8) .


There are plenty of great videos on this versitile chip:
https://www.youtube.com/watch?v=tn5-XiB8oJk
https://www.youtube.com/watch?v=stN-ZzHfiO4

Andrew's module uses 5 of these 555s.
Each is part of an individual one shot circuit.(also known as a Monostable Multivibrator).

It's probably a good idea to install the headers for these ICs along with the other 3 ICs and power connector first.

The other integrated circuits used in this build are two TL072s & one TL074.
The TL07x series are pretty common Op Amps that you will often find in synthesizers.
The TL 072 is a low noise JFET input Op Amp .....commonly used in filters & audio preamps.
The TL074 is a quad Op Amp.
Each of these 4 operational amplifiers incorporates well matched, high-voltage JFET and bipolar transistors. Each op amp has 1 input & 2 outputs (inverting & non-inverting). Voltage is on pins 4 & 11.

But before I install all these, I'll install the resistors, then caps & trannies

The transistors include ten BC 547 & ten BC557.
The BC 547 is a NPN transistor.
The BC 557 is a PNP. The cp capacitors and the transistors form VC resistors that control the pulse width of the signal from each 555.

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     Useful Links:
1.  NLC filter panel
2. NLC notes (5 more)