BlueAsh SC-5

About the BlueAsh SC-5

Inspired by the Ashly SC-50: the BlueAsh SC-5 recreates the original blue-faced 1970s revision of a classic and sought-after American VCA compressor — open, colourful and fast on its feet.

The BlueAsh SC-5 is a feedback VCA compressor that refuses to be pinned to one job. Super-gentle leveling to sweeten a master bus? Done. A distorted, smashed-up drum bus? Also done. Taming lively, dynamic material without squashing the life out of it? That's its home turf. The full parameter set lets you dial in exactly the setting a source needs, and through all of it the unit keeps its own pleasant, characteristic tone — the reason engineers kept the hardware patched in across so many records.

The blue-faced 70s original, modelled circuit by circuit

The blue-faced SC-50 came first, and it earned its reputation on versatility and a musical VCA that flattered almost anything you fed it. We rebuilt that behaviour with our real-time, SPICE-style circuit simulation, modelling every crucial stage as a living circuit: the custom VCA, the dual time-constant detector, the feedback compressor loop and the audio path are all captured component by component rather than baked into a static transfer curve. Because it's a feedback design, gain reduction is derived from the compressor's own output, which gives the BlueAsh its smooth, self-correcting grab. It's a fixed-threshold compressor — you set the amount of compression by driving the input Gain and then make up level with the Output knob.

A colourful, open character with an exceptionally fast attack

What sets the BlueAsh apart is how quick and how musical it is at once. Attack times reach down to a very fast 200µs and stretch to 20ms; release runs from 100ms to 2s; and the Ratio steps from a gentle 1:2 up through 1:2.5, 1:3, 1:5.5, 1:7, 1:10, 1:20, 1:30, 1:100 to a full 1:∞ for outright limiting. Push it lightly and it levels transparently. Push it hard and it colours with a lively, forward character rather than turning dull. Part of that openness is what the blue unit lacks: unlike the BlackAsh, there's no 31.2kHz audio-path lowpass shaving the top, so the BlueAsh stays brighter and more airy. The Link switch sets stereo-linked or dual-mono operation on stereo instances, and the dedicated Limit button bypasses the compressor path alone so you can A/B while the output stage and meters keep running.

Using the BlueAsh SC-5 on drums, guitars, bus and mastering

On drums, the fast attack lets you clamp and pump a bus into a solid, aggressive groove, or back off for punch that still breathes. On electric guitars it tightens dynamics and adds a bit of forward colour that helps a part sit. On the mix bus it glues without smearing, and its clean, transparent side makes it usable in mastering when you only need a decibel or two of controlled leveling. Need more character? Drive the gain for grit; need it invisible? Ease back and use the auto gain compensation — right-drag the Gain knob and Output tracks the opposite direction so the level stays matched. When you want a darker, more aggressive take on the same lineage with an external sidechain on board, its sibling the BlackAsh SC-5 is the companion piece.

BlueAsh SC-5 Features

Fast, musical feedback VCA compression

A custom VCA in a feedback topology delivers the BlueAsh's characteristic grab: gain reduction is derived from the compressor's own output for a smooth, self-correcting response that stays colourful and open even when pushed hard.

Exceptionally fast attack and stepped ratio range

Attack from 200µs to 20ms, release from 100ms to 2s, and a stepped Ratio of 1:2, 1:2.5, 1:3, 1:5.5, 1:7, 1:10, 1:20, 1:30, 1:100 up to a topmost 1:∞ — quick enough to catch drum transients, wide enough to move from gentle leveling to hard limiting on a single source.

Open, bright audio path — no top-end lowpass

Where the BlackAsh runs a 31.2kHz lowpass to darken its tone, the BlueAsh has none: only a sub-1Hz DC-blocking highpass sits in the path. That's a big part of why the blue face stays brighter, airier and more open than its 80s sibling.

Fixed-threshold Gain with auto gain compensation

Set compression by driving the input Gain rather than a threshold knob. Right-drag the Gain knob and the Output moves the opposite way, so you can add compression while the perceived level stays constant and gain-match on the fly.

Stereo link, Limit bypass and live metering

The Link switch selects stereo-linked or dual-mono operation on stereo instances, and the Limit switch bypasses only the compressor path for clean A/B monitoring — with gain-reduction and threshold LEDs, plus a host gain-reduction meter, staying live throughout.

Authentic circuit emulation

Our real-time, SPICE-type component-based circuit simulation captures the sound and feel of the analog counterpart in every nuance — the custom VCA, dual time-constant detector, feedback compressor loop and audio path all faithfully modelled.

SSE2-optimised code

DSP operations are pipelined on the SSE2 instruction set for high-performance operation even under complex processing.

Auto-adjusted oversampling

A low-latency, linear-phase Dolph-Chebyshev polyphase design attenuates aliasing and auto-adjusts to your session's sample rate to save CPU while staying transparent.

HighDPI / Retina support

Crisp high-pixel-density rendering on macOS and Windows for a sharp interface on modern displays.

BlueAsh SC-5 Examples & Videos