Opto Compressor
A smooth, musical compressor with a slower, more forgiving response — transparent and natural-sounding.
What it does
The Opto (optical) compressor is inspired by compressors that use a light-dependent circuit to control gain reduction. The result is a slower, more gradual compression response that is generally less obvious than a fast VCA compressor. It is well-suited to clean tones, jazz, and anywhere you want dynamics controlled without a heavy-handed effect. It handles transients gently and tends to enhance the feel and expressiveness of your playing rather than clamp down on it.
Parameters
| Parameter | Range | Default | What it does |
|---|---|---|---|
| Threshold | −60 to 0 dB | ~−20 dB | The level above which compression begins. Lower it to catch more of the signal |
| Ratio | 1:1 to 20:1 | ~3:1 | How much the signal is reduced above the threshold. Opto compressors rarely need high ratios — 2:1 to 4:1 is typical |
| Attack | 5–200 ms | ~30 ms | How quickly compression kicks in. The Opto's slower minimum attack (5 ms vs 0.1 ms on the VCA) means pick transients are always naturally preserved |
| Release | 50–3000 ms | ~500 ms | How slowly the compressor lets go. Longer release (500 ms+) is characteristic of the smooth, long tail of optical compression |
| Makeup Gain | 0–24 dB | 0 dB | Adds back the volume lost through compression. Adjust so the compressed and bypassed levels match |
| Mix | 0–100% | 100% | Blends compressed and dry signal for parallel compression |
VCA vs Opto — when to use which
| Situation | Recommended |
|---|---|
| Tight, punchy rhythm — country, funk | VCA |
| Smooth clean tone — jazz, blues | Opto |
| Lead guitar sustain | Either — VCA for more control, Opto for more feel |
| Heavy/gain tones | Usually neither — the amp provides natural compression |
| Subtle "glue" across any style | Opto |
Tips
- The Opto shines at subtle settings — Threshold around −15 dB, Ratio 2:1 to 3:1, and makeup gain applied to restore level. You often won't hear it working, but the tone will feel more even and sustained.
- A long release (1000–3000 ms) on clean, arpeggiated playing creates a beautiful bloom effect where each note seems to swell slightly.
- Because the Opto is gentler, you can often set a lower Threshold than you would on a VCA without the compression becoming obvious.