Project Description


SSL6032G+PLUS VU metering . As these consoles are completely custom built CML have designed away to reuse the 688 facility in our custom build consoles, Below is a detailed explanation.

The SSL 6000 console is based largely on the SSL 4000 console, but with its target-market being post-production work in video studios where mixing to stereo output buses was the main objective. There are 3 stereo mix buses which could be used for dialogue, effects and background sound. These buses are referred to as A, B and C. They are separately accessible to both the small fader and the large fader; the large fader can route to any number of the 3 buses whilst the small fader can route to only one at a time. The 3 buses allow for the creation of sub-mixes of the constituent parts of the final mix.

The centre section’s 651 Master Module is only equipped with 4 mix paths and with the A, B & C stereo buses producing 6 mix paths, an additional module was required to handle the mixing and other associated video post-production facilities – this module is the SSL 688.

When undertaking a size-reduction on a large console, the SL688 module remains with the primary console that is produced. The remaining modules, when built up into a console (the secondary console), require summing for the 6 mix buses.
SL651 modules were made by SSL as spares, and it is typically a spare SL651 that is used for the build-up of the secondary console…… but as already noted, the SL651 only has summing for 4 mix buses.


To maximise the facilities when creating a console that has SSL 6000 channel modules, the stereo A, B and C buses require summing; the SL651 Master Module does not succeed as it has a maximum of 4 mix buses; the console requires the SL688 module to do the A, B & C summing (6-bus). The final stereo output from the SL688 is fed into the Front Left & Right Pre-VCA Insert returns of the SL651. (The rear L&R paths are not fitted in the SL651GV Master Module that goes specifically with the 6000 console).
When a SL688 is not available, another summing solution is needed…….

CML Audio has designed a mix system that takes in the A, B and C mix buses, sums them, provides bus inserts and level controlled outputs for the buses. It then takes the A, B & C outputs and does an overall sum of them which is then fed into the SL651 master module Front L&R Pre-VCA Insert Return, as would happen with a SL688 / SL651GV equipped console.

The detail of the CML Audio system.
Each mix path has:
·         Summing amp,
·         Switchable insert point,
·         Rotary level pot (fader),
·         Electronically balanced output stage,
·         Meter driver,
·         Routing switch to send to the final Left & Right outputs.

The construction method that has been adopted is one of a motherboard with sub-boards for each of the circuit blocks.

The motherboard / sub-board construction allows for some interesting options, probably the most significant being that sub-boards / circuit blocks can be fitted that give different “flavours” of sound. With the variety of work that CML Audio does on different consoles, we have at our disposal a range of sub-boards that include mix amps and output amps. Each sub-board of a particular function (e.g. mix amp) is of the same physical size and pin connection, so any mix amp can be placed on a motherboard. At the present time, we have 3 types of Neve mix amp on sub-boards (51-Series, Standard VR & VR Legend), Calrec S-Series and a mix amp of our own design. Other types of mix amp can be created; all that we need is the schematic so as to be able to adapt the design to our board size and pin connections. Theoretically, we could produce mix amps whose circuitry would have originally featured in consoles such as Soudcraft, API, Studer, Focusrite, MCI, Harrison, etc.

A SSL 6000 console that we custom build for A.E.S.  could have Neve VR Legend mix amps on Bus A, API on Bus B and Focusrite on Bus C.

If a customer has a mix amp module or card that they want to have fitted into a console, it may be possible to install the customer’s hardware into the SSL; the output of the customer-supplied mix amps would feed into the ABC system, bypassing the mix amp location by wire links.

I have specifically not said anything about a SSL mix amp being available. This is because the transistors that SSL used in their mix amps, MAT02, were made obsolete by the transistor manufacturer several years ago. Substitute transistors are available, however, they are a very poor substitute for the original and do not meet the low-noise performance of the MAT02. There seems little sense in making a mix amp that would be inferior to mix amps that we have at our disposal. If a customer has original MAT02 transistors, then a SSL mix amp sub-card could be designed.

For a 651 module, we could fit our 026 replacement cards with Neve Legend mix amps on the Front L&R mix paths and, say, API mix amps on the Rear L&R mix paths.

Picture shows SSL6032G+Plus console supplied to Resident Studios London