Taken from the middle section of the Ark input channels,
the NDUCR is the rackmount version of the inductor EQ part of this middle input section.
The NDUCR is designed to add colour to your signal, and silky smooth colour that is.
The NDUCR features 2 channels of 4-band Inductor Equaliser.
No fancy stuff, but just 2 channels with 4-band Inductor EQ.
Going back and forth, the NDUCR was born (feel free to call her “inducer”).
The NDUCR is a 2-channel unit with 4 inductor EQ bands per channel
* The 4-bands are vertically aligned (channel one on the left, channel two on the right)
* Each band can be individually activated / bypassed
* Large frequency select knobs give great hands-on control of selected frequency
* 100 mm level faders offer the finest control of cut and boost
The NDUCR is a 3U 19-inch rackmount unit and is available with “Silver” or “Black” faceplate.
Inductor based circuits are the “holy grail” of equaliser designs.
These were used for example in the much favoured Pultec equaliser design, which dates back to the late 1950’s.
Owing to their unique electro-mechanical properties, inductors impart a character all of their own, which is very distinctive.
The NDUCR uses 32 inductors spread out over the four bands with custom-wound Carnhill inductors in the low-mid and low bands, giving precise control and the inductor sound on each band.
The NDUCR is made of Class-A, discrete electronics. Combined with the inductors you’ll get a very distinctive sound, we have yet to find the engineer who does not love this sound and colour.
However, this circuit is a decidedly modern design with updated techniques and components that were simply not available 60 years ago. This is definitely not a “clone” or “copy”. (we at Interphase Audio do not build clones or copies of anything)
As a consequence of using inductors, this provides a “peaking” characteristic, giving much tighter control of the frequency selected.
The inductor values and components have been carefully chosen and matched to provide an extremely musical sound.
Each band provides switch selection of any of six carefully selected frequencies chosen at musically pleasing intervals.
Each band uses a 100mm fader - instead of a rotary pot - for cut and boost control, allowing very fine control of a maximum of plus or minus 15dB per band.
4-band Inductor EQ
Four bands with switchable, overlapping fequencies
- Low (Hz): 50, 80, 100, 150, 300, 600
- Low Mid (Hz): 125, 250, 500, 1K, 2K, 4K
- Hi Mid (kHz): 1.5, 3, 5, 6, 7, 8
- High (kHz): 8, 9, 10, 12, 14, 16
But why faders instead of rotary controls ?
It’s simple … we like faders.
But faders also offer more precise control of cut or boost, and offer direct visual feedback of the setting of each band.
The NDUCR features 2 inputs and 2 outputs, which are doubled.
Each input has a female XLR and a balanced jack connector. These connectors are paralleled, you can use either.
Outputs have male XLR and balanced jack connectors. These connectors are paralleled, you can use both at the same time.
NDUCR Specifications
• Input impedance: 30kohm
• Common mode rejection: 80dB
• Distortion: 0.001% (+4dBu output, 1kHz)
• Frequency response: 7Hz to 70kHz (-3dB)
• Boost / Cut range: +/-15dB (continuously variable)
• HF Frequency: 8, 9, 10, 12, 14, 16 kHz (stepped)
• HMF Frequency: 1.5, 3, 5, 6, 7, 8 kHz (stepped)
• LMF Frequency: 125, 250, 500, 1k, 2k, 4k Hz (stepped)
• LF Frequency: 50, 80, 100, 150, 300, 600 Hz (stepped)
• Filter Q: 1.2 (just over 1 octave)
• Maximum input level: +32dBu
• Maximum output level: +32dBu (10k load)
• Nominal input and output level: +4dBu (electronically balanced)
• Output impedance: 100 ohm
• Noise floor (typical, unweighted, EQ on): -80dBu
• Noise floor (unweighted, EQ off): -100dBu
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 silky-smooth, polished sound that has made classic consoles and equipment so desirable for over sixty years. This is what makes them different from capacitor-based EQ designs, which do a great job at surgical equalisation. But it has always been up to Inductors to provide the tone.
While some of the inductors we use are off-the-shelf, we also use custom inductors. This attention to detail in controlling variables such as the winding and core materials in relation to the surrounding circuitry allows our Inductor EQ’s to capture the classic sound, while at the same time be up to todays standards in sound-quality and noise level.
The NDUCR features 2 inputs and 2 outputs, which are doubled.
Each input has a female XLR and a balanced jack connector.
These connectors are paralleled, you can use either.
Outputs have male XLR and balanced jack connectors.
These connectors are paralleled, you can use both at the same time.
While you can use both XLR and jack outputs at the same time (for example to split the outputs and send these to multiple destinations),
it is not a good idea to use both XLR and jack inputs at the same time.
There is something very attractive in the sound character of inductor-based equalisers that’s hard to describe — they just sound more natural and ‘right’ to my ears, especially at the bass end of things. It’s probably tied up in the mysteries of phase shifts and waveform distortion, but whatever it is, the Signature Three delivers it well. Overall, this is an unusual inductor-based dual-channel equaliser with all-discrete transistor circuitry that delivers a classy and attractive sound, with well-sorted EQ options. It is very well made — here in the UK — and achieves excellent technical performance. What’s not to like?
Hugh Robjohns from Sound on Sound magazine on the Ocean Audio Signature Three.
Fact: the Ocean Audio Signature Three was NOT designed by Malcolm Toft.
The Signature Three was designed by Allan Bradford, our chief electronics designer.
NDUCR is the new (and much improved) version of the Signature Three, of course designed by Allan.
NDUCR - Inductor EQ
Get yours from our order page
Unique hand-crafted pro audio gear