The Hungry Robot VCF is an all-analog, 4-pole low pass filter with a resonance control, built as a filter pedal for guitar and other instruments. Hungry Robot describes it as a resonant filter with "a beautiful tonal quality," and it sits among filter pedals that sweep the cutoff frequency to reshape a signal's harmonics.1
Controls and patch points
The pedal's controls and connections, as listed by the maker:
| Control or point | What it does |
|---|---|
| FREQUENCY | Sweeps the cutoff frequency of the filter1 |
| IN | Patch audio signal in1 |
| OUT | Patch audio signal out1 |
Beyond the front panel, the cutoff frequency can be controlled by external control voltage. The pedal includes a built-in attenuator and an invert switch for incoming CV, so the amount and direction of the voltage's effect on the cutoff can be set to taste.1
The 2021 update
The VCF was updated in the Spring of 2021 to use a CEM3320 reissue chip, and the two versions differ slightly.
According to Hungry Robot, the update brought two changes:
- The circuit now uses a CEM3320 reissue chip, with small differences in sound and response compared with the first units.1
- An internal "STABILITY" trimpot was added, which allows you to dial in a less stable, grittier filter sound.1
Because the trimpot is internal, it is a set-and-forget adjustment rather than a performance control1.
Power and size
Power requirements depend on which version you own. Surface mount units run on 9V DC through a negative center 2.1mm barrel connector, and through hole units use the same 9V DC negative center 2.1mm barrel. The enclosure measures 4.7" x 2.6".1
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Questions
Is the Hungry Robot VCF analog or digital?
It is all analog. Hungry Robot describes the VCF as an all-analog, 4-pole low pass filter with a resonance control. The Spring 2021 update moved the circuit to a CEM3320 reissue chip, which is still an analog design, though the maker notes small differences in sound and response compared with the first units.
What power supply does the Hungry Robot VCF need?
Surface mount units run on 9V to 12V DC with a negative center 2.1mm barrel connector. Through hole units run on 9V DC with the same negative center 2.1mm barrel. Use a supply that matches the version you own.
What does the Stability trimpot do on the Hungry Robot VCF?
The STABILITY trimpot was added internally with the Spring 2021 update. It lets you dial in a less stable, grittier filter sound, so the filter can be pushed toward a rougher character than the stock setting.
Can the Hungry Robot VCF's cutoff be controlled by external control voltage?
Yes. The cutoff frequency can be controlled by external control voltage, and the pedal has a built-in attenuator and an invert switch for incoming CV, so you can shape how much the external voltage moves the cutoff and in which direction.
How big is the Hungry Robot VCF?
The enclosure measures 4.7 inches by 2.6 inches, according to the maker's product page.
Sources (1)
- VCF | Hungry Robot, Hungry Robot, 2021-03