Iridium - Inductor EQ - 500 series module

  • €699,00
    Unit price per 
Tax included.



The Interphase Audio Iridium is a single-channel 500 series module with 4-band Inductor EQ

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 Iridium uses 16 inductors spread out over the four bands, with custom-wound inductors in the low-mid and low bands, giving precise control and the inductor sound on each band.

Iridium is a Class-A, discrete design, with all components carefully chosen and matched to provide an extremely musical sound. You’ll get a very distinctive sound, which most sound engineers love.

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” or “bell” characteristic, giving tight control of the frequency selected.

Each band provides switch selection of any of 6 carefully selected frequencies chosen at musically pleasing intervals.

Each band allows very fine control of up to 15dB cut or boost per band.

Check out the product page on the Interphase Audio website

Iridium 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 (500 module): +28dBu
• Maximum input level (51x module): +32dBu
• Maximum output level (500 module): +28dBu (10k load)
• Maximum output level (51x module): +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
• I/O connections (Rack XLRs): pin 2 +, pin 3 -, pin 1 ground
• Current requirement: 81mA (maximum) per rail
• Size and weight: Standard 500 Series, 0.75 kilos

Iridium is available in 3 versions:
* as 500 module
* as 51x module
* as DIY kit


All 3 versions are available with “Silver” or “Black” faceplate