Logic gates are great ways to create interesting rhythms or combine triggers from various sequencers.
Recently I've been using them to trigger drum modules.
Some logic gates also work at audio ranges.
There are 7 basic gates: OR, XOR, AND, NOT (inverter), NOR, XNOR, & NAND.
To make things even simplier, the 3 basic fundamental gates are OR, XOR, AND.
They use the inverter (NOT) to make NOR, XNOR, & NAND.
One final grouping of gates is what is known as Universal Gates
A universal gate is a gate which can implement any Boolean function without need
to use any other gate type.
The NAND and NOR gates are universal gates.
These 2 gates are the basic gates used in all IC digital logic families.
--------------------
OR gates
Output a high signal whenever one or more of its inputs are high.
Useful if you wish to combine several gate signals into one.
You can use this instead of a mixer or multiple.
| In1 | In2 | Out |
| 0 | 0 | 0 |
| 1 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 1 | 1 |
XOR Gate (Exclusive OR gate)
Will only output a high signal when one input is high and the other is low.
It allows the signals to pass Except when they happen simultaneously.
It's like when 2 people try to squeeze through a narrow door at the same time.
(use this for your two snare drums - to prevent them triggering simultaneously)
| In1 | In2 | Out |
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
AND gate
Outs a high signal when all its inputs are high.
(If only one input is high it will output a low signal)
| In1 | In2 | Out |
| 0 | 0 | 0 |
| 1 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 1 | 1 |
NOT gate
The above 3 gates are available as
inverted versions (N = not):
OR -----> NOR
XOR -----> XNOR
AND-------> NAND
NOR Gate
This is a OR gate followed by and inverter.
This is quite a useful gate to have, as it's possible to build the other basic logic gates
using only NOR gates.
| In1 | In2 | Out |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
Its output is "true" if both inputs are "false." Otherwise, the output is "false."
XNOR
This is a XOR gate followed by an inverter
| In1 | In2 | Out |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
NAND Gate
This is a AND gate followed by an inverter
| In1 | In2 | Out |
| 0 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
-----------------------------------------------------------------------
For most Eurorack modules:
Low signal = 0V to 1V (usually)
High signal = greater than 1V to 5V (Usually)
Many logic modules respond to continuous CVs like LFOs .
They are reading the CV as a high gate when it
exceeds 1V (usually) and a low gate when it is below.
So they can be used as comparators with a fixed threshold.
The logic synth modules you can buy or build will either use discrete diodes, transistors & resistors,
or use integrated circuit chips. TTL and CMOS are the most common types of ICs.
TTL IC’s may often be labeled as the 7400 series.
CMOS ICs are commonly marked as 4000 series.
Eurorack Logic Modules
+ Elby ED132 - Boolean Logic (Also a Serge Version)
+ Erica Synths - Pico Logic
+ Mystic Circuits ANA
+ Intellijel OR, Plog, Spock , uMod II
+ AniModule LogicOgic, XX_OR
+ 2HP - Logic
+ Mutable Instruments - Kinks (OR & AND gate)
+ Doepfer A-166 (Dual Logic Module) .... AND, OR & NOR, plus two inverters.
+ NLC - Bools, Neuron, Chopper, 8 bit cypher,
+ CGS Funky Drummer
+ CGS Boolean Logic
+ EMW Logic 101, Logic 202
+Wiard /Malekko - JAG
+ Snazzy FX Ardcore
+ Synthrotek - Either-OR Eurorack OR Module
+ Pittsburgh Modular - Logic Banks
+ Analog Ordnance - Logiplex, OR gate,
+ Ladik B-010 Bool2, B-020 Bool3,
+ Circuit Abbey - ANDY, ORY, XORY, VERTY
+ Synth Cube Dual Logic
+ LZX - Castle 100, Castle 101
+ Pulp Logic (1U tiles) -Logical
AND,
OR, Diode-OR,
XOR
Plog - Intelligel
This has AND, OR, NOR, XOR, NAND, and XNOR gates
RYO
NOT, XNOR, NOR, OR, NAND, AND
Links
,,,
