B-Series Dynamics Module

Aggressive character compressor in 500 Series format

New analogue flavour, vintage SSL sound 

The 4000 B Dynamics (B-DYN) 500 series module takes the dynamics processor found in the channel strip of the SL 4000 B console and puts it into 500 Series format. Released in 1976, the 4000 B was the first console ever manufactured by Solid State Logic and was famously used in ‘The Stone Room’ at Virgin’s Townhouse Studio (London), Le Studio (Montreal) and Record Plant (LA). It was responsible for countless iconic records, including Phil Collins’ ‘In the Air Tonight’ and Peter Gabriel’s ‘Intruder’, both of which feature characterful compression on drums and vocals. The B-DYN module allows users to add heavily coloured, grabby, saturated compression from one of the rarest studio consoles ever made to their production toolkit.

Its own unique sonic signature

The dynamics Section in the SL 4000 B console channel strip was unlike any other SSL channel dynamics module that followed, using the fader VCA as its gain element, rather than a dedicated VCA. It had a design similar to the topology of the SSL Bus Compressor. This VCA ‘feedback’ design has been inherited by the B-DYN module, offering characterful and coloured compression, with its own unique sonic signature - very different from the later E and 9000 Series. These similarities are also evident from B-DYN’s ‘Auto’ release setting, which offers a program-dependent release time as found on the Bus Compressor.


  • Authentic recreation of SL 4000 B consoles dynamics processing
  • Design based on the SSL Bus Compressor
  • Feature Compressor/Limiter & Gate/Expander
  • Feedback design with Peak sensing for aggressive ‘grabby’ character
  • Fixed compression ratios, 2:1, 4:1 & 10:1 with an additional ‘DS’ mode
  • Fixed release times, DS, .2, .4, .8, 1.6 & renowned ‘Auto’
  • Auto make-up gain
  • Sidechain high pass filter
  • Stereo Link mode
  • New (vintage) SSL flavour for your productions

SSL 4K B-DYN Overview and Tutorial


RATIO - Stepped compression ratios 2:1, 4:1, 10:1 and ‘ds’. The ‘ds’ setting is a fixed 10:1 with an additional sidechain filter. When ‘out, the compressor is bypassed    

THRESH - Whenever a signal exceeds the level set by this control, the compressor will start to act at the ratio set by the RATIO control. The THRESH’old and RATIO controls also provide automatic make-up gain. A small improvement to the linearity of this control has been made in the module over the original channel strip control. This helps with Threshold tuning using the smaller scale 500 series knobs.    

HPF - A 6dB/Oct 185 Hz High Pass Filter in the compressor sidechain to help reduce bass pumping effects  

RELEASE - Switched/fixed release ranges from .2 ms to 1.6 ms with additional ‘DS’ & AUTO release options.   

DS - The De-Ess mode changes the attack time from approx. 30 ms to 2 ms. 

De-Ess (DS) mode

By setting COMPRESSOR RATIO and RELEASE controls to ‘DS’ the B-DYN module is optimised for reducing sibilance (De-Essing). The De-Ess ratio is a 10:1 ratio with filtered S/C input signal, delivering broadband compression triggered by sibilance typically in vocal sources. The ‘DS’ release is automatically varied in response to the processed signal between release rates of 30 & 50 ms. This is a much faster minimum release than you would normally expect from an SSL Dynamics section. The Attack time is also reduced to a fast 2 ms, slightly faster than the E-Series Dynamic module on its FAST setting)


The B-DYN Gate & Expander section can act as a 20:1 Gate or as a 2:1 Expander when the EXP button is pressed.  

RANGE - Controls the maximum amount of gain reduction applied by the gate/expander. When set to ‘out’, the gate/expander is bypassed.  

THRESH - Sets the threshold above which the the gate/ expander will be opened.   

RELEASE - Sets how long the signal remains audible after the gate/expander closes.  

EXP - Switches the gate to expander mode with a gentle curve, for subtler control of level below the threshold. 

The attack time of the expander/gate is a fast 0.2 ms.


SSL Studio Tools Brochure


E- Series EQ Module User Guide


E-Series EQ module - Recall Sheet