Prior to 1987 SSL used the colour of the Low Frequency EQ knob caps to indicate which type of EQ was fitted. All consoles were custom built and could feature different combinations of EQ module. The following colour codes apply:
E-Series BROWN: The original SSL EQ fitted to all consoles prior to the summer of 1985. Despite the rumours these equalisers only came in one version. The EQ card was called the '02'.
E Series ORANGE: The infamous EQP equaliser. This was a variation on the Brown EQ with controls simulating the curves of a valve type EQ. Very few were sold. This card was named the '132'.
E-Series BLACK: The last version of the standard E series EQ. It evolved in the early 1980's from discussions with many top engineers and proved very popular. The EQ card was called the '242'.
G-Series: With the arrival of the G Series console in 1987 the colour coding was abandoned and the classic SSL end cap colour scheme used today was adopted. First introduced in 1987 the original G Series EQ introduced Q characteristics which were proportional to gain settings and had a degree of over shoot when boosting and under shoot when cutting.
The current generation of SuperAnalogue console EQ (featured on Duality, AWS 900 + SE & the X-Rack EQ module) are switchable between EQ characteristics that offer either the E-Series 'Black' EQ or the G Series EQ.
The 'Brown' EQ, featured on the discontinued SSL E-Signature Channel Strip, is now uniquely available on the E-Series EQ Module.