Solid State Logic The Bus+
The Bus+ combines a feature-rich analogue SSL Bus Compressor with a powerful Dynamic EQ, all in a single 2U rack unit
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 centre 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 colouration 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, we 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 we 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, we 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 Equaliser 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, we decided to give The Bus+ 4 unique operating modes. Alongside the known and loved Classic Stereo mode, a S/C Stereo mode is available, as found in our 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.
The Bus+ (General)
- The Bus+ combines a feature-rich analogue SSL Bus Compressor with a powerful Dynamic EQ, all in a single 2U rack unit
- 100% analogue circuit, controlled digitally using the stepped front-panel pots
- 4 modes of operation – Classic Stereo, S/C Stereo, Dual Mono or Mid-Side
- Huge +27.5 dBu headroom
- External side-chain inputs and sends
- 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
Bus Compressor
- The ultimate incarnation of the SSL Bus Compressor
- The authentic SSL Bus Compressor circuit utilising high-performance 2181 THAT VCAs
- 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 time constant options – more flexibility to shape the Bus Compressor, including the new ‘Auto 2’ setting
- Precision MDAC-controlled MAKE-UP Gain with two ranges available – ‘Coarse’ 1 dB steps or ‘Fine’ 0.5 dB steps
- Variable side-chain High-Pass Filter control up to 300 Hz in 10 Hz steps
- MIX control for instant parallel compression
- Moving-coil gain reduction meters
- Unlockable bonus mode: Transient Expander
D-EQ
- An all-new, powerful 2-band analogue Dynamic EQ
- 2-band (LF and HF), parallel Dynamic Equaliser
- 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/ 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-colour activity LEDs to indicate D-EQ activity
- Individually bypass-able bands