Ljunggren Audio
Roll Your Own
Eurorack DIY
Boolean Logic
Discrete Resistor-Transistor-Logic
The circuitries of the RYO logic gate modules are directly modeled after the very earliest form of digital logic gate designs using resistor-transistor-logic (RTL) pioneered in the 1950s and used in computing equipment throughout the 50s and 60s. The Apollo Guidance Computer for instance used the same type of 3-input NOR gate design now found in the RYO NOR/OR module, although in vastly greater numbers.
The RTL circuit design gives the modules some interesting quirks thanks to the transistors threshold windows when playing around with different amplitudes, waveforms and frequency rates of the incoming signals, making it fun and useful to explore beyond typical logic gating duties, for example as an audio waveshaper/distortion.
NOR/OR
Download assembly manual here. (1.5MB)
The NOR/OR module can be patched as two NOT gates,
one NOT gate and one 2- or 3-input NOR/OR gate,
one 2-input NOR/OR gate and one 2- or 3-input NOR/OR gate
or one 4-input NOR/OR gate.
Gate one has three inputs, the second has two. The OR out from gate one is being normalled to input 1 on gate two.
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Basic specifications
Width: 4 hp
Depth: 45 mm.
Power +12V: 14 mA @ 5V input signals
28 mA @ 10V input signals
Power -12V: 0 mA
Power +5V: 0mA
XNOR/XOR/NOT
Download assembly manual here. (1.7MB)
The XNOR/XOR/NOT module can be patched as two NOT gates and one 2-input XOR gate,
one NOT gate, one 2-input XOR gate and one 2-input XNOR/XOR gate,
two 2-input XNOR/XOR gates
or one NOT gate and one 3-input XNOR/XOR gate.
Gate one and two has two inputs, the third has one. The XOR out from gate one is being normalled to input 1 on gate two. The XOR out from gate two is being normalled to the single input on gate three (NOT).
Download assembly manual here. (1.7MB)
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Basic specifications
Width: 4 hp
Depth: 50 mm.
Power +12V: 14 mA @ 5V input signals
28 mA @ 10V input signals
Power -12V: 0 mA
Power +5V: 0mA
NAND/AND
Download assembly manual here. (1.5MB)
The NAND/AND module can be patched as two NOT gates,
one NOT gate and one 2- or 3-input NAND/AND gate,
one 2-input NAND/AND gate and one 2- or 3-input NAND/AND gate
or one 4-input NAND/AND gate.
Gate one has three inputs, the second has two. The inputs on gate one is normalled in a 1>2>3 fashion for efficient cable and time-saving patching. The inputs on gate two has also been normalled 1>2, with the AND out from gate one in turn being normalled to input 1 on gate two.
Download assembly manual here. (1.5MB)
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Basic specifications
Width: 4 hp
Depth: 45 mm.
Power +12V: 14 mA @ 5V input signals
28 mA @ 10V input signals
Power -12V: 0 mA
Power +5V: 0mA
* Regarding our PCB/panel only offerings, please note that these are mainly offered due to popular demand from the experienced DIY community. Hence we are counting on that you know what you are doing and how to source parts. If you feel the least bit uncertain, please consider going for the kit.