AJH SynthEntropic Doom Noisillator

AJH Synth Entropic Doom

The AJH Entropic Doom Noisillator is a unique noise source, capable of a wide range of tuned noise sounds, with ring modulation and a logic-based VCA. Rather than using reversed biased transistor or zener diode, the Entropic Doom uses a CMOS logic gate-based noise generator. This allows the noise signal to be synced to external signals and introduces frequency control.

The noise is in a feedback loop with a pass band resonator and a low pass filter with 2, 3, or 4-pole modes. Audio can also be introduced into this feedback loop, adding a new dimension of noise mayhem. The pass band filter includes a resonance control which makes the noise more filtered and pitched. The noisillator features two outputs: bright, taken directly from the noise source, and dark, taken after the low pass filter and pass band resonator.

The ring mod section uses a CMOS XOR logic gate in order to create the ring mod effect. However, because it uses a logic gate as the source of the ring mod, the output is active even when only one signal is present. Additionally, the XOR logic distorts the input signal and causes it to "square up", turning it into a pulse waveform. The X ring mod input is also connected to the XOR VCA. A unipolar signal between 0 and +5V can be used to amplify that signal. The VCA behaves similar to a standard linear VCA but because it uses logic gates, the output is turned into a pulse waveform and it distorts the input signal. This is particularly pronounced at higher gain settings. Although there is no normalled connection between the Noisillator and the ring mod/VCA, they work great in tandem—so patch them together freely.

Entropic Doom Features

• Noise oscillator and XOR amplitude modulation
• Logic-based tuned noise oscillator
• 2, 3, or 4-pole low pass filter
• Pass band resonator with resonance control
• Sync input for noise
• Tracks 1V/oct
• XOR ring mod
• XOR VCA with level control
• Introduce audio into the noise feedback path
• Pre and post filter noise outputs
• Fine control CV input