Helium - Hybrid EQ - 500 series module

  • €639,00
    Unit price per 
  • Save €160
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The Interphase Audio Helium is a single-channel 500 series module with 4-band Hybrid EQ

Helium combines capacitor based EQ circuits and filters with inductor based EQ circuits.

Helium is the combination of our Carbon and Iridium EQ, with extra filter circuits added.

Helium is a full Class-A, discrete design, and all components have been carefully chosen and matched to provide an extremely musical sound.

This is definitely not a “clone” or “copy” (we at Interphase Audio do not build clones or copies of anything).

Like all our products, Helium is unique and features great sound and straight forward functionality.

The four bands have large overlapping frequency controls, making it well-suited for minimising problematic frequencies, or giving an extra boost to others.

The HF and LF band can be used as either bell-curved EQ or as HI-Cut / Lo-Cut filter.

Each band can be cut or boost with as much as 15dB per band.

Check out the product page on the Interphase Audio website


• 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: 1.2 kHz - 22 kHz (continuously variable)
• HF Frequency switchable to 12 dB per octave sweepable Hi-Cut filter 1.2 kHz - 22 kHz
• HMF Frequency: 1.5, 3, 5 6, 7, 8 kHz (stepped)
• LMF Frequency: 125, 250, 500, 1k, 2k, 4k Hz (stepped)
• LF Frequency: 25 Hz - 440 Hz (continuously variable)
• LF Frequency switchable to 12 dB per octave sweepable Lo-Cut filter 25 Hz - 440 Hz
• 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: 129mA (maximum) per rail
• Size and weight: Standard 500 Series, 0.7 kilos

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

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