COMPRESSOR

Compressor with VCA in the Operational Amplifier Feedback Loop

How a feedback compressor works

Unlike feedforward compressors, where the control signal is taken from the input, in feedback compressors, the control signal is taken from the output. This allows the circuit to more accurately adjust to the already compressed signal.
The main components of such a circuit are:

• Operational Amplifier (Op-Amp): Used for amplifying and processing the audio signal. Components in its feedback loop determine the characteristics of the compressor.
• VCA (Voltage-Controlled Amplifier): An amplifier whose gain is controlled by a control voltage. It is placed in the feedback loop of the Op-Amp, and its gain changes depending on the output signal level.
• Envelope Detector: Tracks the output signal level and generates a control voltage for the VCA.
• Control Circuit: Composed of resistors and capacitors that set the compressor’s parameters, such as attack time (trigger speed) and release time (return to the initial state).

Advantages of feedback compression:

• Transparency: The signal attenuation occurs smoothly without abrupt jumps, making the compression less noticeable and more "musical."
• Excellent dynamics: Perfect for handling peak and transient signals, which are characteristic of guitar playing.
• Sustain: The compressor evens out loud and quiet notes, increasing sustain (duration of the sound).

Features for guitar:

• Musicality: Unlike feedforward compressors, this circuit doesn't immediately clip transients but responds more smoothly and adaptively. This preserves the natural attack of the sound while ensuring a smooth and long sustain.

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Controls :
Volume - Output Level
Attack - Speed / Intensity of Attack
Ratio - Degree of compression sustain
Blend - mixes the clean input signal and compressed signal.

Passive true bypass.
Need external 9 VDC /120 mA power supply (not included).

€120
€10 - Shipping (worldwide)