SSL THE BUS+ Bus Compressor

They've been on a mission to create the ultimate and most versatile incarnation of the Bus Compressor ever. The bedrock of the design remains faithful to the original circuit and using this as the foundation, they've built upon it, adding several unique coloration options and advanced processing tools. If you need it to be clean and punchy like the SuperAnalogueTM 9000 Series version, it can be. If you need it to be gritty and grungy like an early 4000E, it can do that also. Or if you need over-the-top, saturated, parallel compression for the drums, THE BUS+ has got you covered.

THE BUS+ circuit design utilizes high-grade components, including 2181 THAT VCAs for superior analogue performance, four modes of operation and 3 distinct compression coloration options which can be combined to perfectly suit the genre you’re working on. THE BUS+ also packs in sophisticated routing options and advanced processing tools: Dynamic Equalizer (D-EQ), Transient Expander and so much more…

Innovation

To complement the new feature set, SSL sought to bring improvements that would benefit recallability and technical performance.

All of the pots on THE BUS+ are stepped and read by a microcontroller which translates the pots position into the required circuit configuration or electrical parameter. This innovative approach not only makes recall significantly easier, it also means THE BUS+ is not subject to pot tolerances – perfect for precision processing applications like mastering.

Dynamic Analogue Equalizer: D-EQ

THE BUS+ incorporates a host of advanced processing tools including the new Dynamic Analogue Equalizer (D-EQ).

The D-EQ is a powerful 2-band Dynamic EQ that can be placed before or after The Bus Compressor. Many engineers are familiar with Dynamic EQ plug-ins inside the DAW but analogue Dynamic EQs are few and far between.

A Dynamic EQ is a more 'intelligent' form of EQ that changes the gain of an EQ band proportionally in response to the signal level once above a set threshold. It allows you to modify the contrast between background material (under threshold) and forward material (above threshold).

Advanced processing tools

While the core design of THE BUS+ remains faithful to the original, a number of advanced processing tools have been added to create the most versatile Bus Compressor ever. In addition to D-EQ and Transient Expander, THE BUS+ features three unique compression colors; LOW THD, F/B and 4K MODE. Each ‘color’ offers a different characteristic and can be combined for very unique compression styles.

LOW THD MODE introduces a special circuit modification in the side-chain, helping to limit the amount of low frequency distortion compression can create, especially with fast release times. Subjectively, LOW THD 'cleans up' the bottom-end, allowing you to achieve 'cleaner' gain reduction.

F/B (FEED-BACK) MODE takes the signal feeding the side-chain from a feed-back position (i.e. after the main gain-reduction VCA in the audio path). This results in a more 'relaxed' style of compression, in contrast to the traditional 'grab' of the Bus Compressor.

4K MODE changes the operation of the VCA from balanced to unbalanced (matching how the Bus Compressor in a 4000-series console was implemented). It also introduces a variable amount of harmonic distortion via the VCA. These two factors combine to allow for a more 'colored' sound. THE BUS+ allows you to adjust the distortion amount which 4K MODE offers. You'll find there's a certain 'sweet spot' (depending on your mix level) in which your material will become more cohesive, thanks to the added thickness.

D-EQ

After a considerable amount of research and development, SSL is proud to introduce the first ever SSL Dynamic EQ (the D-EQ) as part of THE BUS+. The side-chain is a specially adapted version of the Bus Compressor side-chain with additional circuitry such as the gain reduction limiter for the Range parameter. SSL considers the D-EQ is every bit as musical and powerful as the Bus Compressor itself. The D-EQ can enhance the top and bottom end of your mix with ease, making it an extremely powerful companion alongside the Bus Compressor.

The D-EQ is a 2-band parallel Dynamic EQ. Each band has 16 frequency points to choose from, allowing complete control over which part of the frequency spectrum you want to affect. The High Frequency band can also be changed from a shelf filter to bell curve.

Compression / Expansion: Each band has a 31-position stepped control labelled with COMP and EXP at the extremes of the control. As you turn the control clockwise from the center position '0' (no effect), you start dialing in an expansion effect. Moving the control anti-clockwise, you start dialing in a compression effect.

Features:

Bus Compressor:

4 modes of operation - Classic Stereo, Σ S/C Stereo, Dual Mono or Mid-Side
External side-chain inputs and sends
The authentic SSL Bus Compressor circuit
LOW THD Mode reduces low-frequency distortion caused by compression
F/B Mode alters the compression characteristics for a more 'relaxed' style of compression
4K Mode - single VCA operation with variable harmonic distortion to bring some 'grit' and 'grunge' to the mix
Negative Ratios - for creative pumping effects and control of particularly loud signals
New Attack and Release options, including the new 'Auto 2' setting
MIX control for instant parallel compression
Moving-coil gain reduction meters
Unlockable Transient Expander

D-EQ:

Powerful 2-band analogue Parallel Dynamic EQ - the D-EQ
Compress/Expand modes
3 choices of time constants for each band - Nominal, FAST, or AUTO
16 selectable Frequency points per band
Adjustable Range control per band from 0.5 dB to 15 dB
HF band can be switched to Bell shape, with selectable frequencies covering High-Mids and Highs
Frequency band static 'make-up' gain for LF and HF bands (Stereo/ Σ S/C Stereo) or LF band (Dual Mono/Mid-Side)
G-Series mode changes LF filter to be 2nd order with degree of undershoot/overshoot
Tri-color activity LEDs to indicate D-EQ activity
Individually bypass-able bands

General:

100% analogue circuit, controlled digitally using stepped front-panel pots
Huge +27.5 dBu headroom
Configurable processing order - Bus Compressor pre D-EQ (default) or post
CH 1 IN and CH 2 IN buttons for global bypass
Settable Operating Level - 0 dB (nominal), +10 dB, -5 dB
Sleep and Auto-Sleep modes
Precision MDAC-controlled MAKE-UP Gain with two ranges - 1 dB or 0.5 dB steps

Specifications:

Number of Channels: 2
Threshold: +20dB
EQ: 2-band EQ
Frequency Response: 20Hz-20kHz
Inputs: 2 x XLR, 2 x XLR (EXT S/C)
Outputs: 2 x XLR, 2 x XLR (EXT Send)
Rack Spaces: 2U
Power Source: Standard IEC AC cable (Included)
Height: 3.5 Inches
Depth: 11.9 Inches
Width: 19 Inches
Weight: 21.2 Pounds
Processor Type: 2-channel Bus Compressor

LEARN MORE ABOUT THE BUS+

The Bus Compressor Legacy: If there is a single piece of analogue processing equipment that is synonymous with SSL, it just has to be The SSL Bus Compressor. From the very first commercially released SSL 4000 B console in 1976 and through many generations of SSL consoles that have followed since, the Bus Compressor has always been the stalwart of the console center section. In 1991, when SSL took its first steps into the analogue outboard world, the FX G384 saw the Bus Compressor put into rackmount form, meaning that studios without SSL consoles could use it. In 2002, the FX G384 received a face-lift, with a new silver front panel taking it into the X Logic era and this was followed by the multi-channel 5.1 version the following year. In 2007, the Bus Compressor became available as double-width module for the X-Rack series and in 2013, the Bus Compressor made it's way into the ever-popular 500-series format. Even if you've never had chance to experience SSL Bus Compressor 'in real life', then you will have undoubtedly come across it in plug-in form, perhaps by using the SSL Native Bus Compressor 2. One thing is for sure, throughout the course of music production history, the Bus Compressor has always been the de facto choice for gluing a mix together.

Creating The Ultimate: For the past two and a half years we've been hard at work engineering The Bus+, on a mission to create the ultimate and most versatile incarnation of the Bus Compressor ever seen. The bedrock of the design remains faithful, as it always has done, to the original circuit and using this base as the starting point, we've built upon it, adding a number of unique coloration options. If you need it to be clean and punchy like the X Logic version, it can be. If you need it to be gritty and grungy like an early 4K, it can do that also. Or, if you need to it to do something a little different, we've got you covered.

To complement the new feature set, SSL also sought to bring improvements that would benefit recallability and technical performance. Firstly, this led to a decision to make all of the pots on The Bus+ stepped. Every pot is either an 11 or 31-position stepped control and this has the obvious advantage of making recalls easier... but there's actually more cleverness going on here. Stepped pots on their own may make recalls easier but simply using them instead of continuous pots doesn't lead to any technical advantage per se, as they are still subject to mechanical tolerances that can compromise stereo matching and the overall analogue performance.

So SSL went even further, coming up with an innovative approach to the implementation. On The Bus+, all the stepped pot positions are read by an on-board microcontroller, meaning that no audio actually passes through the pots themselves and by doing this, SSL are no longer subject to the pot tolerances. The microcontroller's job is to translate the pot positions into the required circuit configuration or electrical parameter. To be clear, The Bus+ is a 100% analogue circuit design, it's just managed in a clever way. This approach is extended to the front panel buttons, providing clean and reliable switching of analogue signals thanks to the use of electronic switches.

In conjunction with the technical and general feature improvements, The Bus+ incorporates an all-new Dynamic Analogue Equalizer section, which we've named the D-EQ. The D-EQ is a powerful 2-band Dynamic EQ that can be placed before or after The Bus Compressor. Many engineers are familiar with Dynamic EQ plug-ins inside the DAW but analogue Dynamic EQs are few and far between. A Dynamic EQ is a more 'intelligent' form of EQ that changes the gain of an EQ band proportionally in response to the signal level once above a set threshold. It allows you to modify the contrast between background material (under threshold) and forward material (above threshold). The D-EQ is built upon a specially adapted version of the Bus Compressor side-chain circuit, which contributes significantly to its powerful, yet musical sonic character. Being able to use the D-EQ in conjunction with The Bus Compressor makes for some very exciting dynamic and tonal options indeed.

To round off the design, SSL decided to give The Bus+ 4 unique operating modes. Alongside the known and loved Classic Stereo mode, a Σ S/C Stereo mode is available, as found in SSL’s Duality console. Mid Side allows you to tailor the final mix/master stereo image and Dual Mono is super useful for tracking purposes or creative stem use. The Bus+ is truly a treasure chest of compression options at your disposal.

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