The 551 Inductor EQ by RND, is actually the single the only 500 format module designed by Rupert Neve, and incorporates key features and the tonal character of vintage Neve designs. The 551 has two peak / shelf style EQ’s for selectable high and low frequencies respectively. There is also a single parametric mid frequency band.
The 3-band, custom-tapped inductor EQ on the 551 was inspired by RND’s favorite portions of Rupert’s vintage EQ designs. The low frequency band is designed to produce a creamy, resonant bass response – however, unlike the vintage modules that inspired it, the LF 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 12dB/octave design with a fixed 80Hz frequency, and can be used in tandem with the low frequency EQ to add low-end presence without clouding the source material.
As Rupert originally intended with his most prized classic designs, each EQ section uses low-feedback, class-A discrete electronics to prevent low-level artifacts and harshness from detracting from the tonal shaping. However, this new circuit is a decidedly modern design with updated techniques and components that were simply not available 35 years ago, and should not be considered a “clone”.
Rupert Neve Designs 551 Specifications:
Noise: Measured at Main Output, un-weighted, 22Hz-22kHz, source impedance 40 Ohms balanced. Better than -102dBV
Frequency Response: Main output, no load +/- 0.1dBu from 20Hz to 31.5kHz -1dB @ 120kHz
Maximum Output Level: 23.25dBu
Total Harmonic Distortion and Noise: @ 1kHz, +20dBu output level, no load. Better than 0.0025% @ 20Hz, +20dBu output level, no load. 0.13% Typical (2nd and 3rd harmonic)
High Pass Filter: -2.7dB @ 80Hz Slope: 12dB/Octave Equalizer Engaged
Noise: Measured at Main Output, un-weighted, 22Hz-22kHz, source impedance 40 Ohms balanced. Better than -94dBV
Frequency Response: Main output, no load +/- 0.25dBu from 20Hz to 45kHz -2dB @ 120kHz
Maximum Output Level: 23dBu
Total Harmonic Distortion and Noise: @ 1kHz, +20dBu output level, no load. Better than 0.009% @ 20Hz, +20dBu output level, no load. 0.13% Typical (2nd and 3rd harmonic)
Power Requirements: 120mA on +16VDC 110ma on -16VDC
Requires 500 series rack / power supply to operate. Sold separately.