Description

The vintage EQ tones you know & love.
The 551 is the only equalizer for the 500 Series actually designed by Rupert Neve. Featuring 3 bands of EQ inspired by Mr. Neves most prized vintage designs, along with custom-wound inductors, transformers and class-A gain blocks, the 551 brings the thick, powerful lows and sweet highs of Ruperts classics to the 500-Series format.

The Best-Of EQ
The 551s 3-band, custom-tapped inductor EQ was inspired by our favorite elements of Ruperts vintage EQ designs. The low frequency band is designed to produce a creamy, resonant bass response similar to a vintage 1064 but unlike the vintage modules, 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 midrange band is based on that of the 1073, 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 with Ruperts 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 50 years ago, and is definitely not a clone.

What Are Inductors?
Inductors are wires wound around a coil that provide a form of frequency-dependant resistance. When they saturate, they bring out beautifully musical harmonics that give your tracks the smooth, polished sound that has made Ruperts consoles and equipment so desirable for over fifty years. This is what makes them different from capacitor-based EQ designs, which do a great job at surgical equalization. But inductors provide the tone.

While it is certainly possible to create a functioning EQ using off-the-shelf inductors, we choose to use our own custom inductors for the 551. This attention to detail in controlling variables such as the winding and core materials in relation to the surrounding circuitry allows the 551 to capture the vitality and personality of Ruperts classic designs.

NOISE

• Measured at Main Output, un-weighted, 22Hz-22kHz, source impedance 40 Ohm balanced.
• Better than -102 dBV

FREQUENCY RESPONSE
Main output, no load: +/- 0.1 dBu from 20 Hz to 31.5 kHz, -1 dB @ 120 kHz

MAXIMUM OUTPUT LEVEL
23.25 dBu

TOTAL HARMONIC DISTORTION AND NOISE

• @ 1 kHz, +20 dBu output level, no load: Better than 0.0025%
• @ 20 Hz, +20 dBu output level, no load: 0.13% Typical (2nd and 3rd harmonic)

HIGH PASS FILTER

• -2.7 dB @ 80 Hz
• Slope: 12 dB/Octave

NOISE

• Measured at Main Output, un-weighted, 22 Hz – 22 kHz, source impedance 40 Ohm balanced.
• Better than -94 dBV

FREQUENCY RESPONSE
Main output, no load: +/- 0.25 dBu from 20 Hz to 45 kHz, -2 dB @ 120 kHz

MAXIMUM OUTPUT LEVEL
23 dBu

TOTAL HARMONIC DISTORTION AND NOISE

• @ 1 kHz, +20 dBu output level, no load: Better than 0.009%
• @ 20 Hz, +20 dBu output level, no load: 0.13% Typical (2nd and 3rd harmonic)

POWER REQUIREMENTS

• 120mA on +16VDC
• 110ma on -16VDC