Solid State Logic X-Rack E-Series EQ Module

SKU: SSL X-Rack 4000 Series EQ
$ 1,069.00

The SSL E-Series EQ Module is the X-Rack-format equalizer taken from the SL 4000 E console channel strip, which has figured prominently in the sound of chart-topping music from the ’80s through today

When SSL introduced the SL 4000 E console in the 1980s, it set the recording industry on its ear (so to speak). SSL didn’t just create a mixing desk, they crafted a musical instrument that in the hands of master artisans such as Chris Lord-Alge and Bob Clearmountain, has contributed to sound we associate with popular music—and nothing affects the timbral quality of music like an equalizer, particularly the one found on every channel of the E-series desk. Not just a reissue of a single console EQ, the E-Series EQ Module lets you switch between two different equalizers found on editions of the console produced between 1979 and 1987. The equalizers are differentiated by the color of the knobs on the low-frequency section. The earlier console iteration is known as the Brown EQ (card 02), which was followed by the Black EQ (card 242), the result of feedback from top engineers. Each EQ has the unique response curves and tonal character of the original Brown and Black channel equalizers. Of special note, the Brown equalizer was featured on the SSL E-Signature Channel, which was discontinued, now back in Brown on the X-Rack E-Series EQ Module.  

SSL X-Rack E-Series EQ Module—Just the Facts:

  • Immortal SSL 4000 E Series circuitry
  • "Black-242" and "Brown-02" twin EQ design
  • Bell curve option on HF and LF
  • Fully parametric LMF and HMF with Q
  • Based on classic 611E console channel strip

SSL X-Rack E-Series EQ Module—Under the Hood

Brown Knob EQ

The E-Series module defaults to the original Brown Knob circuit that was standard on all early production E Series consoles. The BLK button switches the module to emulate the later Black Knob circuit. You can also switch the entire EQ section out of your X-Rack channel strip via the In button.

With the BLK button out, the two parametric mid-band sections feature SSL’s classic logarithmically symmetric design that ensures the ±3dB up/down points retain the same musical interval from the center frequency regardless of frequency and amplitude settings. The two shelving sections are traditional 6dB/octave designs with an option for a fixed Q parametric response (Bell). The 02 EQ (Brown), to give it its proper name, was used on countless recordings and mixes in the early eighties.

Black Knob EQ

In 1983 a new “242” EQ circuit was developed in conjunction with the late Sir George Martin for the first SSL console to be installed in AIR studios. The “Black Knob” EQ, as it became known, featured enhanced cut and boost ranges (±18dB instead of ±15dB) combined with a different control law and a steeper 18dB/octave high-pass filter for tighter control of low frequencies.

For added flexibility, the module input and output gain can be set to operate at a nominal level of either +4dBu or –10dBV, using a switch on the connector panel. Plus, you get recallability via the X-Rack’s Total Recall feature.

SSL E-Series EQ Module controls

This is a four-band equalizer that can be switched between two different sets of curves; one based on SSL’s ‘02’ (‘Brown Knob’) EQ and the other based on the latest version of the classic ‘242’ E Series (‘Black Knob’) EQ.

HF Band controls:

  • Frequency: Variable from 1.5kHz to 16kHz
  • Gain: Variable between ±15dB (Brown) Variable between ±18dB (Black)
  • “Q” (on BELL setting): 0.8 (Brown); 1.3 (Black)

HMF Band controls:

  • Frequency: Variable from 600Hz to 7kHz
  • Gain: Variable between ±15dB (Brown) Variable between ±18dB (Black)
  • “Q”: Variable from 0.5 to 2.5 (Brown); Variable from 0.5 to 4 (Black)

LMF Band controls:

  • Frequency: Variable from 200Hz to 2.5kHz
  • Gain: Variable between ±15dB (Brown) Variable between ±18dB (Black)
  • “Q”: Variable from 0.5 to 2.5 (Brown); Variable from 0.5 to 4 (Black)

LF Band controls:

  • Frequency: Variable from 30Hz to 450Hz  
  • Gain: Variable between ±15dB (Brown) Variable between ±18dB (Black)
  • “Q” (on BELL setting): 0.8 (Brown) 1.3 (Black)

SSL console EQ history

The classic equalizers of the SL 4000 E and G consoles have made their mark on more hit records than any other console. SSL 4000 consoles are still in use today by top mixers, including Chris Lord-Alge and Bob Clearmountain, while Michael Brauer uses the XL 9000 J. The current generation of SuperAnalogue console EQ (featured on Duality, AWS, and the mono X-Rack EQ Module) is switchable between EQ characteristics that offer either the E Series 'Black' EQ or the G Series EQ. Prior to 1987 SSL used the color 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 color codes apply:

E Series Brown: The original SSL EQ fitted to all consoles prior to the summer of 1985. Despite the rumors, these equalizers only came in one version. The EQ card was called the “02”.

E Series Orange: The infamous EQP equalizer. This was a variation on the Brown EQ with controls simulating the curves of a valve-type EQ (the Pultec). 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 1980s 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 color coding was abandoned and the classic SSL end-cap color 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 overshoot when boosting and undershoot when cutting.

If you’ve been longing for a vintage SL 4000 E console, but don’t have the space, budget, or desire for a 5-figure monthly electric bill, the SSL X-Rack E-Series EQ Module lets you build E-series channels strips to your heart’s content. For more information, call or chat online with your PAD Studio Specialist.

  • Frequency Response: ±0.5dB from 20Hz to 20kHz; –6dB at 100kHz
  • THD + N: < 0.003% at +20dBu 1kHz; < 0.003% at +20dBu 10kHz
  • Output Headroom: > +26dBu at onset of clipping
  • Noise: < –80dBu (+4dBu operating level); < –92dBu (–10dBV operating level

Dimensions (approx.)

  • Depth: 7-15/16" / 200 mm (including front panel knobs, excluding connectors)
  • Depth: 10-15/16" / 275 mm (including front panel knobs and connectors)
  • Height: 6-3/4" / 171 mm
  • Width (Front/rear panels): 1-3/8" / 35mm
  • Overall width (front and rear panels are offset): 1-15/16" / 49 mm
  • Weight: 9.5 oz. / 260g

Measurement References

  • Reference frequency: 1kHz
  • Reference level: 0dBu, where 0dBu ≈ 0.775V into any load
  • Source impedance of Test Set: 50 ohm
  • Input impedance of Test Set: 100k ohm
  • All un-weighted measurements are specified as 22Hz to 22kHz band limited RMS and are expressed in units of dBu
  • All distortion measurements are specified with a 36dB/Octave low-pass filter at 80kHz and are expressed as a percentage
  • The onset of clipping (for headroom measurements) should be taken as 1% THD Unless otherwise quoted all figures have a tolerance of ±0.5dB or 5%
  • All measurements are made with the operating level switch set for +4dBu


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