Hi SSL dudes
In the early days when I worked at SSL (starting in 1980 till 87), I think the original concept was to have the efx returns brought back onto the centre section and just routed (without TR) to the stereo mix buss. This was the case when the consoles were 24-32 channels as standard back around 1980.
As time went on, and within a few years, the consoles got much larger (from 32 to 48 and even 72 channels) which meant that, with the extra channels, studio owners and engineers could afford the luxury of having efx returns routed back into channels, each with more eq, dynamics, and TR instead.
Therefore the efx return section of the centre section almost became redundant as it had limited facitllies.
I am doing some wiring for an Oram Pro24 console at the moment and the people involved have no idea about that same concept so, I have just positioned those centre section aux returns (fed from some efx outputs) onto a patchbay, so they can plug them into somewhere else if required.
Hope this makes some sense?
PS: I need to do some more wiring posts? Anyone with wiring problems which need addressing? Please post them in the wiring menu and I will address them (I look every week or so but contact me directly if it is urgent).
PPS: I don't have an SSL. Worked there for 7 years in the early days, bought one and broke it up to sell and have installed loads of them. And I am a drummer, so have experienced both sides of the glass (musician in a studio and a wiring installer)!