Rupert Neve Designs 551 Inductor EQ

The 551 Inductor EQ from Rupert Neve Designs is a three-band EQ with custom-wound inductors, transformers, and class-A gain blocks. The low-frequency band on the 551 can be used as either a shelf or a peak filter, adding punch, dimension, and control to your low end.

The 551’s inductor midrange band is ideal for sweetening vocals and instruments while bringing them forward in a mix, and its proportional “Q” response makes it well suited for minimizing problematic frequencies. The high-frequency band is a hybrid vintage/modern design, blending inductor circuitry with capacitor-based topologies to achieve vintage tones with enhanced control.

The high-pass filter is a 12 dB/octave design with a fixed 80 Hz frequency, and can be used in tandem with the low-frequency EQ to add low-end presence without clouding the source material.

Both the high and low band can be switched from shelf to peak curves and offer 15 dB of boost or cut. The high band can be switched from 8 to 16 kHz, and the low band can be selected at 35, 60, 100, or 220 Hz.

The inductor-based mid band offers six center frequencies: 200, 350, and 700 Hz, and 1.5, 3, and 6 kHz. The mid band also has an “MF Hi Q” switch to narrow the bandwidth (increase the Q) of the filter.

• Engages all bands of the equalizer except the hpf
• Adjusts up to 15 dB of boost or cut at selected low, mid, and high frequencies
• Four different EQ curves to finesse the high-frequency content
• Peak mode utilizes an inductor and capacitor circuit to create the bell-shaped curve
• MID FREQ rotary switch has six positions to select the center frequency of the mid-band EQ stage: 200, 350, and 700 Hz, and 1.5, 3, and 6 kHz
• Engages a 12 dB per octave high-pass filter set to 80 Hz
• Four LOW FREQ options: 35, 60, 100, and 220 Hz