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Saturation Box
Tube, tape, and transformer saturation
Saturation Box is four analog saturators built on real circuit physics: a 12AX7 triode, an EL84 pentode, tape, and an iron-core transformer. It responds to how you play, not just how loud you are. Warm when you nudge it, feral when you push it.
Free · Available · VST3 / AU · v0.3.1 · macOS (Universal, Apple Silicon & Intel)
Details
Features
- Four models from circuit and magnetics physics: Triode (12AX7 preamp stage), Pentode (EL84 push-pull output stage), Tape (456-class oxide at 15 ips), and Transformer (nickel-core line transformer)
- Program-dependent by design: grid blocking, bias bloom, and supply sag react to your playing
- Auto Gain holds the level as you turn Drive, so you judge the character, not the volume. Switch it off for hardware behavior.
- Phase-coherent Mix for parallel saturation, with no comb filtering
- Saturation band: confine the color to a frequency range, stay clean outside it
- True bypass, click-free and tied to your host's bypass. Vintage for an older tube or an older tape.
- Nine factory presets and a VU meter that shows how hard you're driving
- Oversampled to 176 kHz or above at any host rate, linear-phase
Getting set up
Install
- Download the .pkg installer below.
- Run it. AU and VST3 land in /Library/Audio/Plug-Ins automatically.
- Restart your DAW, or rescan your plugins.
- Insert Saturation Box where you want color: tracks, busses, or the mix.
You'll need
- macOS 11 or later, Apple Silicon or Intel (universal binary)
- A DAW that hosts AU or VST3 (Logic, Live, Cubase, Reaper, and friends)
- Notarized by Apple, no Gatekeeper workarounds needed
Questions
FAQ
- Is it really free?
- Free at launch, yes. Your email gets you the download and release notes, nothing else. If we ever charge for it, the version you grabbed stays yours.
- Will it add latency?
- It reports its small oversampling latency to your DAW, which compensates automatically: 61 samples at 44.1/48 kHz (about 1.4 ms), 49 at 88.2/96 kHz, and none at 176.4/192 kHz. That honesty is what keeps the Mix knob phase-coherent: parallel blends stay perfectly aligned instead of comb filtering.
- Which model should I start with?
- Triode on vocals and bus glue, pentode on drums that should bark, tape on the mix bus, transformer on bass. Then break those rules.
- What about Intel Macs or Windows?
- Intel and Apple Silicon are both covered; the binary is universal. Windows isn't here yet; write to hello@adrestia-audio.com. Demand decides the roadmap.
Changelog
Versions
v0.3.1October 9, 2026Latest
- Andrestia Audio is now Adrestia Audio. New name on the panel, in the plugin metadata, and at adrestia-audio.com. Bundle identifiers are unchanged, so existing sessions keep loading.
- Triode Drive goes further. The Triode was the only model whose knob stopped short of overdrive, so at the same Drive setting it sat thin next to the other three. The grid now swings three times hotter: at Drive 25 on a drum loop the tails sit at +5 dB, between the Transformer and the Pentode, and at full Drive it compresses about 13 dB instead of 6. Harmonics at operating level are 0.6 / 2.3 / 5.5 % second-harmonic at Drive 0 / 12 / 24. Level compensation recalibrated; noise floors and aliasing unchanged.
v0.3.0October 8, 2026
- A major update. Each of the four models is now modeled as the actual circuit rather than a curve that approximates it, so every one of them sounds closer to the gear it is named after.
- Triode is a 12AX7 stage with its coupling and cathode capacitors in the model. Hit it hard and the bias shifts and swells back the way a real stage does. Nearly clean at low Drive, second-harmonic warmth as you push it. Drive is scaled to a real single stage, and it uses about a quarter of the CPU it did.
- Pentode is an EL84 push-pull output stage, which is where that odd-harmonic British crunch comes from. The power supply sags under a loud hit, about 2 dB over the first 200 ms, and recovers.
- Tape is an oxide curve fitted to a 456-class tape at 15 ips. The highs saturate first, so transients round off naturally, and there is no envelope follower in it anymore, so nothing pumps. Drive is now record level, so the whole knob is useful. Vintage switches to an older, softer, noisier tape stock on a slightly worn head.
- Transformer is iron that saturates where iron really does, down low, while the mids stay clean. At high Drive it is the line amplifier driving the transformer that runs out of rail.
- Fixed: a notch in the Mix blend around the Low Cut and High Cut frequencies. The blend is now flat within 0.2 dB.
- Fixed: tube aliasing cut by about 40 dB, and some low-frequency and sub-sonic artifacts on the tube models cleaned up. Silence is now -100 dBFS on every model.
- New: a true Bypass button, click-free, tied to your host's bypass. The panel dims while it is engaged.
- New: a hardware panel. Leather, brushed metal, round model keys that light up, and jewel lamps for Bypass, Vintage, and Auto Gain that flicker a little more the harder you drive it.
- Noise is now per model, at the real levels of the gear, placed where each circuit makes it, and it fades out when nothing is playing. No hum, no crackle.
- Each model has its own voicing now instead of a shared tone shape: Triode keeps its natural high-frequency roll-off, Tape its record emphasis and head bump.
- Oversampling follows your sample rate (4× at 44.1/48 kHz, 2× at 88.2/96, none at 176.4/192), so CPU at 96 and 192 kHz dropped a lot. Latency is 61, 49, or 0 samples, reported to the host.
- Manual for v0.3.0 (PDF)
v0.2.0September 24, 2026
- Auto Gain is now a switch on the panel, on by default. On, the level holds steady as you turn Drive so you hear the character change. Off, the unit behaves like the hardware: unity at Drive 0, louder as you push it.
- Level compensation recalibrated on real program material instead of a test tone. Drive is now flat to within 0.1 dB at operating level on all four models; the old tables let it rise about 4 dB, and 7 dB on Transformer.
- Bypass no longer shifts the track in time or clicks.
- The noise floor now stays put: the same on every model, and it no longer climbs with Drive. Vintage hisses like a machine that's been loved, not neglected.
- Fast automation of Low Cut and High Cut is now smooth.
- Preset name is saved with the session. Tooltips on every control. Shift-drag for fine control, double-click to reset a knob.
- Manual for v0.2.0 (PDF)
v0.1.2September 23, 2026
- Resizable window. Drag the corner, or click the size badge in the footer for 100-200% presets. The size is remembered per instance and as a global default for new ones.
- New Andrestia Audio logo in the header. The plugin name moves to the footer.
v0.1.1September 21, 2026
- Switching between models no longer clicks or pops. Changes crossfade over 20 ms, and a reset bug that fired a full-scale spike when switching to Transformer is fixed.
- Fixes a bug where the plugin would not load on macOS versions before 26. Now runs on macOS 11 and later.
- Footer version label now reflects the installed build.
v0.1.0July 19, 2026
- First public release.
- Four saturation models: Triode (12AX7), Pentode (EL84), Tape, and Transformer.
- Loudness-compensated Drive, phase-coherent Mix, saturation band, VU meter.
- Nine factory presets, exposed to the host program list.
- AU and VST3 for macOS, universal binary.
Saturation Box. Ready when you are.
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