What an optical compressor is
An optical compressor uses an optical cell (a light source along a light detector – light-dependent resistor, LDR), as the name suggests, to attenuate the input signal and achieve compression.
Every compressors generally work with a gain reduction circuit that compresses the audio signal in response to a control signal. This control signal is derived from the input audio signal and it is part of the so called sidechain. The sidechain can be an external audio signal and it is controlled by the compressor parameters: the threshold and ratio plus the attack and release times.
The LDR will behave according to the amount of light it receives. This will effectively control the attenuation of the gain reduction circuit. The attack and release times along with the ratio and threshold controls can be adjustable.
Due to the nature of the LDR component, optical compressors generally exhibit a ‘soft knee’ compression curve.
MCAudioLab’s new 2309 compressor is the blend of vintage sound approach and modern technology.
The 2309 is an original design, not inspired by legendary optical compressor; not imitating or pretending to be a clone of… Just the smooth compression of the optical devices drived us to create such audio gear.
The 2309 is a discrete Class A single ended design, transformersless input and output. The MCAudioLab 816 Discrete OpAmp is the core of the compressor that features the perfect balance of tones and details with a solid, slightly coloured sound, airy top and fatty basses. The 2309 has smooth enought compression as you have the feeling it is not working until you switch the bypass. But the unit can be an aggressive compressor, too. It’s your decision as you have the full control on every single parameter.
The 2309 fully features a variable attack, variable release and three different style of compression. Two linkable channels to be closely matched to be used on master bus, sub bus, as well as on bass, drums, synths, vocals, acoustic and electric guitars and more.
MCAudiolab 2309 has two completely independent channels with linking switch option for driving the two channells with the same setup; hard bypass switches for each channel; separate sidechain inserts and independent compression contour. Low noise, wide bandwidth and great transient response.
Two simple parameters to get the right level of compression: Peak and Drive (when and how much compressing). PEAK – sets the level of compression, from 0 (no compression) to Max (heavy compression) with the ‘soft knee’ action. DRIVE – sets the amount of compression applied to the signal.
OUTPUT – sets the output markup gain from mute to +6dB.
STYLE: 3 position switch for the compressor behaviour. Set the style of compression from hard (Kick) to powerfull (Push) to smooth (Spank).
ATTACK – 6 position switch with attack time settings from Slow to Fast. Don’t you want to compress but just ‘colouring’ the track? Use the unique OFF funcion and the signal will pass through the discrete class-A circuitry for that analog flavoured sound.
RELEASE – 5 position switch with recovery time settings from Slow to Fast. Variable Attack and Release time are set via stepped rotary switches.
METER – shows the compression rate for an immediate and an easy reading of the amount of compression.
BYPASS – toggle switch used to hard wire bypass the 2309.
LINK – using link switches, the two channells can be linked for dual-mono operation(*).
EETERNAL SIDECHAIN – this switch engages the side chain insert. The 2309 compressor feature a side chain insert point per channel, so you can apply an equalization to the signal to control certain parts of the audio spectrum; the 2309 can turn into a de-esser or every creative tool your fantasy is able to figure out. The external insert can also be used to “key” the 2309 from another sound source for that sorts of creative pumping effects.
(*)The two channels of the 2309 are not factory matched. When the Link switch is on and in order to get a stereo compression, the Peak and the Output controls must be set separately as they keep affecting the related channel they belong to.
- Two channels – Class A Opto Compressor
- Single ended design
- Fully discrete circuit
- MCAudioLab 816 DOA
- Transformerless input and output
- Fully variable attack
- Fully variable release
- Fully variable ratio
- Three compression styles
- Active MakeUp gain
- Linkable channels
- Hard Bypass switch
- External Sidechain
- LED compression rate meter
- Special OFF function