NDUCR Rackmount Inductor EQ

The Interphase Audio NDUCR is the rackmount version of the inductor EQ section found in the middle of the Ark input channels. It adds rich, silky colour to your signal and gives you the musical character that engineers love. If you want an NDUCR that delivers classic inductor tone in a practical rack format, this unit brings that sound straight into your setup.

The NDUCR gives you two channels of 4-band Inductor Equaliser control. We designed it after a friend and highly respected sound engineer asked us to build a rackmount version of our Ark Inductor EQ. He wanted something simple and focused: two channels, four EQ bands, and no extra distractions. From that idea, the NDUCR took shape.

Each unit places the two channels vertically for fast workflow. Channel one sits on the left, and channel two sits on the right. In addition, each band can be switched in or out individually, so you can shape only the parts of the signal you need. Large frequency select knobs make it easy to choose the right frequency, while the 100 mm faders give you precise control over cut and boost.

Inductor based circuits are the “holy grail” of equaliser designs.

The NDUCR uses inductor-based circuits, which many engineers consider the holy grail of equaliser design. For example, the famous Pultec equaliser helped define the sound of classic recording gear in the late 1950s. Inductors create a distinctive electro-mechanical character, and that character gives the EQ its smooth and musical response.

Inside the NDUCR, you will find 32 inductors across the four bands. Custom-wound Carnhill inductors handle the low-mid and low bands. As a result, you get accurate control and the unmistakable inductor sound on every band. The circuit also uses Class-A discrete electronics, so it delivers a bold and distinctive tone. However, this is a modern design, not a clone or copy. We used current components and updated techniques to build something original and reliable.

Each band offers six carefully chosen stepped frequencies. These frequencies sit at musical intervals, so you can make confident EQ moves quickly. The 100 mm faders provide up to ±15 dB of continuously variable boost or cut. Therefore, you can make subtle adjustments or stronger tonal changes with great precision.

We chose faders instead of rotary controls for a simple reason: they feel great to use. Moreover, they give you finer control and clear visual feedback at a glance.

The NDUCR includes 2 inputs and 2 outputs, each doubled. Every input has both a female XLR and a balanced jack connector, and you can use either one because they are paralleled. Likewise, each output offers both male XLR and balanced jack connectors, so you can use both at the same time if needed.

The unit comes in a 3U 19-inch rackmount format and is available with a Silver or Black faceplate.

Interphase Audio NDUCR Specifications:

• Input impedance: 30 kohm
• Common mode rejection: 80 dB
• Distortion: 0.001% (+4 dBu output, 1 kHz)
• Frequency response: 7 Hz to 70 kHz (-3 dB)
• Boost / cut range: ±15 dB, continuously variable
• HF frequency: 8, 9, 10, 12, 14, 16 kHz
• HMF frequency: 1.5, 3, 5, 6, 7, 8 kHz
• LMF frequency: 125, 250, 500, 1k, 2k, 4k Hz
• LF frequency: 50, 80, 100, 150, 300, 600 Hz
• Filter Q: 1.2
• Maximum input level: +32 dBu
• Maximum output level: +32 dBu (10k load)
• Nominal input and output level: +4 dBu, electronically balanced
• Output impedance: 100 ohm
• Noise floor, typical, unweighted, EQ on: -80 dBu
• Noise floor, unweighted, EQ off: -100 dBu

Related products

• EQ 2.2
• EQ 2.2-VU
• TK Audio TK-lizer 2
• Interphase audio