DigiTech VCS-1 Dynamics Processor

The DigiTech VCS-1 is designed to give you precise control over dynamics in digital recording, analogue recording, and live performance. The VCS-1 features an adjustable-gain vacuum tube stage with analogue VU metering and LED peak indicators. Its compression circuit uses the latest solid-state VCA components, ensuring minimal noise or colouration, even under heavy compression. The attack and release timings are based on a “True Logarithmic Compression” design, emulating the natural sound of vintage compressors.

The DigiTech VCS-1’s vacuum tube amplification stage employs a classic high plate-voltage, pure class A design with a parallel-triode configuration and a fully regulated 235V plate supply, maximising signal-to-noise ratio and transient response. It uses premium-grade 12AX7A vacuum tubes, hand-tested and graded by Audio Glassic in the USA and manufactured in Russia.

Precision 1% metal-film resistors are used throughout the audio path for stable performance and low noise, while high-quality plastic-film capacitors in the filter circuits ensure spectral accuracy and long-term reliability. Each DigiTech VCS-1 undergoes rigorous performance testing and a 24-hour burn-in period to guarantee years of reliable operation.

DigiTech VCS-1 Features

• Fast, quiet industry standard VCA circuitry with “True Logarithmic Compression” timing
• Dual Class A vacuum tube stages
• Convenient single knob De-ess control
• Input, Output and Gain Reduction VU metering with LED peak indication
• Peak limiter circuit for transient peak protection
• Gate feature with variable attenuation level
• XLR and TRS 1/4” balanced inputs and outputs
• Sidechain loop for frequency-sensitive compression and gating

DigiTech VCS-1 Application Notes

Vocals: For most vocal tracks, light compression is recommended, unless the vocalist has exceptional microphone control. A common approach is to start with a 2:1 compression ratio when recording and later adjust based on the mix’s density. Compression tends to enhance lip smacks, breathing, and other sounds, which may need gating. It can also increase sibilance, requiring the use of a De-esser to compensate.

Drums: Compression is great for adding punch to drums without increasing level or EQ. Compress the bass drum and snare separately, but you can compress rack toms as a stereo mix. Try a slow manual attack time and an 8:1 ratio, which allows percussive transients through while controlling low-frequency noise. The Soft knee setting can help maintain the initial “tick” of the drum before compression kicks in.

Bass: Bass guitar can be very dynamic, especially with pop/slap techniques. Without compression, peaks may distort, and quieter notes might get lost in the mix. Start with a 4:1 ratio and the Auto setting, which is ideal for controlling release time on sustained notes. For more sustain and a fuller mix, increase the ratio. Slower attack times in manual mode can highlight the sound of a pick on round wound strings.

Mixdown: If your individual tracks were lightly compressed or not compressed at all, you might want to apply some overall compression during mixdown. However, be cautious – mastering is typically best left to professionals. Compression can be helpful when dubbing from DAT to cassette, as cassettes have less dynamic range. Start with the Auto setting and a 2:1 ratio to manage dynamics in mixed program material effectively.

Peak Limiting
Peak limiting is crucial for live-to-digital recording to prevent distortion from unexpected volume spikes. As performers often play louder than during sound checks, the DigiTech VCS-1’s peak limiter helps reduce transient peaks that cause digital distortion while leaving dynamics below the threshold unaffected. Set the Threshold control to the maximum level allowed for your recorder, typically 0 VU. Since 0 VU can vary between manufacturers, begin by setting the Limiter Threshold to +10 dBu. For extra protection, engage the compressor at a 2:1 ratio with the threshold just below the limiter setting.

Gating
A gate is commonly used to lower the noise floor raised by compression and eliminate unwanted low-level sounds in instrument or vocal tracks. It can also reduce ambient noise in microphones used for vocals or announcements. For more advanced use, a sidechain processor can modify the gate’s behaviour, discussed in the Sidechain section.

De-essing
The DigiTech VCS-1’s De-esser is tailored for vocal use, applying gain reduction to sibilant sounds in speech or singing. Excessive sibilance usually results from heavy compression or high-mid EQ boosts, which enhance vocal clarity but can also amplify harsh high frequencies. Start with a 6 dB de-ess attenuation and review the entire vocal track. If sibilance is higher than the DigiTech VCS-1’s 4.5 kHz range, an equalizer can be connected to the sidechain to pinpoint the problematic frequency. The VCS-1’s broadband de-esser attenuates all frequencies at once, as sibilance and vowels generally do not overlap.

Sidechain
A sidechain allows for frequency-sensitive compression by inserting an equalizer. This EQ alters which frequencies trigger the compressor without affecting the overall frequency balance. For instance, boosting frequencies above 4 kHz results in de-essing, while cutting low frequencies reduces sensitivity to bass drums. Additional uses include making the compressor more responsive to cymbals or guitar amp frequencies or adjusting a gate’s sensitivity to specific frequencies.

Sidechain gating can also enhance the bass track by dynamically linking it to the bass drum. For example, feeding the bass drum track into the sidechain return and sending the bass guitar track to the DigiTech VCS-1’s input allows the gate to open in sync with the bass drum, adding a slight dynamic boost to the bass track.