GMS-1310MU Compressor/Limiter

Feed-forward VCA based Compressor/Limiter has Soft-Knee, Variable Ratio, Attack and Release

The flexible GMS-1310MU Compressor/Limiter module is a feed-forward compressor that uses a low distortion Blackmer gain cell for level control driven by a true RMS level detection circuit. Compression threshold, attack, release and compression ratio are controlled from panel controls. A high pass side chain filter can be enabled to prevent over-compression of low frequencies. A hard/soft knee control selects the behavior of the compressor at the threshold point. A makeup gain control adjusts the output level to compensate for the gain reduction and to raise low level information.

Two or more of the 1MU wide modules can be coupled for stereo compression. A front panel switch allow the stereo coupling to be enabled. A front panel bypass switch is provided to help evaluate compression settings against the uncompressed input. An external side chain input adds versatility to the compressor and allows external processing of the audio fed to the RMS detector. The side chain high pass filter can be used with either the internal or external side chain paths. 


The compressor has an external side chain input to the amplitude detector that can be used to route a modified version of the compressor input signal when for example, the compressor is used as a "de-esser" to remove sibilance in the 7KHz region. This input could also be used for ducking a bass part when driven with a kick drum signal. This input is engaged by a panel switch.

A 12dB per octave high pass filter can be introduced into the sidechain audio path with a front panel switch. This filter can be used to attenuate low frequency side chain information to prevent excessive compression of low frequencies. This prevents the perceptual dulling of the compressed audio as high frequencies are over compressed. The frequency knee of the filter has an adjustment range from 10Hz to 250Hz. The side chain filter can be used with either the internal sidechain path or the external sidechain input.


The attack and release times are continuously variable with front panel controls. The attack time can be varied from 0.1msec to 15msec. The release time range is 1.0msec to 160msec. 


The threshold or point at which compression begins is variable over a range of  -30dB to +10dB. The compression ratio or slope of gain reduction that occurs above the threshold is variable over a range of 1:1 to Infinity:1, the later ratio essentially being a limiting ratio.


An LED gain reduction meter indicates the current amount of gain reduction being applied to the input signal.

A hard knee/soft knee switch controls how the slope of the gain reduction effect occurs at the threshold level. Hard knee causes a sudden transition to the slope of the gain reduction curve. Soft knee causes a gradual change of the slope into the gain reduction curve.


Technical Specifications

Typical Input Impedance
100K Ohms

Output Impedance
1K Ohms(short circuit protection)

Threshold Level
-30dB - +10dB

Compression Ratio
1:1 - Infinity:1

Attack Time
0.1msec - 16msec

Release Time
1msec - 160msec

Makeup Gain
-20dB - +20dB

Total Harmonic Distortion
0.07 %

Output Noise
(0dB gain)


Module Power
+15 Volts 45 mA.
-15 Volts 45 mA.

Module Size
Panel height - 8.75 inches (222 mm)
Panel width - 2.125 inches (54 mm)
Depth (behind panel) 2.1 inches (53 mm)



We produce electronic synthesizer modules in the two most popular formats, MU (Moog compatible 5U) and EU (Eurorack compatible 3U). A wide range of voltage controlled modules including oscillators, amplifiers, mixers, envelope generators, special effects units, wave generators, filters, power systems and cases allow users complete freedom to configure any desired electronic music instrument.


Grove Audio builds microphones, preamplifiers, equalizers, compressors and other professional audio equipment for performance and studio use. We build units in popular formats such as 19 inch rack mount and 500 series 3U modules. We can also produce custom designs on request. Contact us for a consultation.


You can explore all of our products, download spec sheets, and purchase our products in the Grove Audio Synth Store. You can also learn about our periodic specials and new product introductions. Click the button below to go directly to the store.

Follow Us!

Grove Audio Help
  • Email:
  • Phone: 608 886-6503


Grove Audio has been manufacturing professional recording and modularized electronics for musicians and performers since 1995.