Interphase Audio Helium 4-Band Hybrid Equaliser
Interphase Audio Helium is a 4-band hybrid equaliser built for tone shaping with precision and musicality. It combines capacitor-based EQ circuits and filters with inductor-based EQ circuits to deliver a flexible sound that works across a wide range of recording and mixing tasks.
Helium is the result of the Carbon and Iridium designs, with additional filter circuits added for even more control. As a result, you get a powerful equaliser that lets you shape problem frequencies, enhance key elements, and add character without losing clarity.
This unit uses a full Class-A discrete design. In addition, every component has been carefully selected and matched to support a smooth, musical response. Interphase Audio does not build clones or copies, so Helium stands on its own as a distinctive and original design. It also focuses on straightforward operation, which makes it easy to use in fast-paced studio workflows.
Custom-wound Carnhill inductors
The four bands offer wide overlapping frequency ranges. Because of that, you can target troublesome frequencies with accuracy or boost important areas with confidence. The HF and LF bands can work as bell EQs, or they can switch to 12 dB per octave hi-cut and lo-cut filters. Meanwhile, the two middle bands use inductive EQ circuitry, including custom-wound Carnhill inductors on the low-mid band. This combination gives Helium a versatile tone with plenty of flexibility.
Each band provides up to 15 dB of boost or cut. Therefore, you can make subtle adjustments or bold tonal changes depending on the source material and the sound you want to achieve.
Interphase Audio Helium is available as an Octa module or as a 500 series module. You can also choose between Silver and Black faceplates to match your setup. Whether you need a detailed corrective EQ or a musical tone-shaping tool, Helium delivers a refined and reliable solution.
If you want a hybrid equaliser that combines character, control, and simplicity, Helium is an excellent choice. It fits naturally into modern studio chains and offers the kind of response that encourages confident mixing decisions.
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: 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 (Octa module): +32dBu
• Maximum output level (500 module): +28dBu (10k load)
• Maximum output level (Octa 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
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