The SSL G Bus Compressor is a stereo compressor that was adapted from the on-board compressor of the classic SSL 4000 series consoles. Possibly one of the most-used mix bus compressors in commercial music, The G Bus Comp is known for its effect of bringing a track together with a sense of cohesion or ‘glue’.
Solid State Logic consoles are considered by many to be the benchmark for mixing desks and the built-in bus compressor is no small part of this reputation. The G Bus Compressor takes this iconic piece out of the large-format console and into a standalone unit (offering both a standard rack housing and a 500-Series module) that can be integrated into any studio. For a time, SSL also produced a multi-channel version of the G Bus Comp for surround use, however this has been discontinued in favour of their surround-capable consoles.
The G Bus uses a VCA (Voltage Controlled Amplifier) to achieve gain reduction. As is typical of this type of design, it can work very fast while retaining clarity and imparting little distortion. When set to apply small amounts of gain reduction with a slower attack time, the G Bus imparts punch and excitement while retaining dynamics and giving the feeling of elements of the mix ‘gluing’ together and sounding like a finished product.
While predominantly a mix bus tool, the G Bus compressor fares equally on a drum sub-group. When applied subtly, it can tuck kicks and snares back into the mix to allow more controlled overall dynamics. When cranked up, the ‘squash’ and ‘pop’ of the G Bus makes for an incredible parallel compressor on drums with an unmistakably modern quality.
Like many pieces of equipment of this prestige, the SSL G Bus Compressor is often emulated (or at least the basis of design) by other manufacturers, though for many the SSL remains the unbeatable weapon of choice.
Source impedence 50 ohms unless otherwise stated
All measurements are made in RMS and are made using a 22Hz to 22kHz filter unless otherwise stated.
Input terminated with 50 ohms. Compressor switched in and Makeup set for 0dB gain.
Noise: < -90dBu
Headroom is defined at the output level at which THD exceeds 1%
Headroom: > +28dBu output level, 20Hz to 20kHz at 0dB gain
Dynamic Range: > 118dB
Input level +20dBu, ground referenced
20Hz to 10kHz: > 50dB
THD + Noise
Gain +0dB, input level +4dBu. Compressor switched out.
20Hz to 20kHz (80kHz filter: < 0.008%, typically 0.005%
Gain +0dB, input level +20dBu. Compressor switched out.
20Hz to 20kHz (80kHz filter): < 0.01%, typically < 0.006%
THD with the compressor switched in is dependent on attack and release times and signal content.
Apply +20dBu test tone to either channel input with the other input terminated with 50 ohms. Crosstalk is the ratio of the level at the output of the test channel and the output of the channel to which the signal is applied.
Crosstalk @ 50Hz: < -110dB
Crosstalk @ 1kHz: < -100dB
Input impedance: > 10k ohms
Output impedance: < 50 ohms
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