The Mighty Helios Returns
Within high-end studio circles, Helios consoles are spoken about with hushed reverence. This desk was a mainstay at Olympic Studios, where it was used to create legendary albums from Jimi Hendrix, Led Zeppelin, the Rolling Stones, Eric Clapton, Black Sabbath, Jethro Tull, and many others — it's the sound of late-1960s British rock. Armed with an 0011 mic preamp/EQ and an F760 compressor/limiter, the H2 Audio Helios Channel packs this entire classic recording chain into a convenient 2U rack unit. You also get a custom Acme Audio Motown DI input transformer, +48V phantom power, and a dedicated output fader control. The Helios Channel also permits you to deploy it as a complete channel strip or as separate units with individual rear-panel inputs and outputs. Moreover, high-quality ELMA gold-plated rotary switches, gold-plated toggle switches, and sealed conductive-plastic pots ensure optimal sound and long-term reliability. No matter how big or small your studio is, the H2 Audio Helios Channel will equip your setup with one of the most sought-after analog recording chains ever devised.
Related Videos: Helios Channel
2128 preamp circuit
The Helios Channel's 0011 mic preamp/EQ section includes a meticulous re-creation of a Helios 2128 preamp circuit, arming you with 25–75dB of gain in 5dB increments, and it boasts a Lustraphone input transformer, providing you with +20dB of gain before the preamplifier. You get plenty of baked-in features, including a -20dB pad, +48V phantom power, an EQ Cut switch, and a Phase switch. The Helios Channel brandishes an electronically balanced line input, a transformer-balanced line output amplifier, and a custom output transformer, and it yields a 600-ohm drive capability of up to 25dB before clipping. The engineers here at Sweetwater frequently turn to the Helios Channel's DI input, which is equipped with an Acme Audio Motown input transformer for an ear-grabbing Hitsville-style flavor.
5011 inductor-based EQ
Also in the H2 Audio Helios Channel's 0011 mic preamp/EQ section is a 5011 inductor-based equalizer with selectable low- and mid-frequency controls and a fixed 10kHz high-frequency control. This EQ includes a highpass filter with 0, 40Hz, and 80Hz filter points. Its Bass Hz rotary switch includes a selectable 60Hz, 100Hz, 200Hz, or 300Hz boost, or a variable 50Hz filter with a selectable 3dB, 6dB, 9dB, 12dB, or 15dB cut. Its Mid kHz rotary switch includes a selectable 0.7kHz, 1kHz, 1.4kHz, 2kHz, 2.8kHz, 3.5kHz, 4.5kHz, or 6kHz boost or cut. Its 10kHz rotary switch will create a bell-shaped boost or cut at 10kHz by -2dB, -4dB, -6dB, -8dB, -10dB, +2dB, +4dB, +6dB, +8dB, or +10dB. Plus, a PK/TR switch denotes the midrange EQ as peak or trough, while a Pre O/P control adds +10dB of gain to the unit's output stage for distorted preamp effects.
F760 compressor/limiter
The Audio Design & Recording's vaunted F760 FET comp forms the basis of the Helios Channel's compressor/limiter section. Sporting a custom transformer-balanced input and output, the F760 is arguably one of the best-kept secrets in recording. Its Comp I/P knob lets you dial in your preferred amount of compression; its Ratio rotary switch gives you six pre-selected ratios/thresholds. Meanwhile, the Attack rotary switch includes selectable 0.25mS, 0.5mS, 1mS, 2.5mS, 10mS, or 25mS attack times; and its Release Sec rotary switch gives you .025s, 0.05s, 0.1s, 0.2s, 0.4s, 0.8s, 1.6s, or 3.2s release times. You also get an A setting that deploys an auto dual-platform release function, allowing for fast transient recovery or a build-up slow release. Beyond that, its Limit Only/Comp+Lim switch enables you to bypass the compressor for limiter-only operation.
H2 Audio Helios Channel Features:
- Packs the sound of a legendary Helios console into a 2U rackmount channel strip
- Includes 0011 mic preamp/EQ and F760 compressor/limiter sections
- Helios 2128 preamp circuit arms you with 25–75dB of gain in 5dB increments
- Lustraphone input transformer provides +20dB of gain before the preamplifier
- -20dB pad, +48V phantom power, an EQ Cut switch, and a Phase switch
- Custom Acme Audio Motown DI input transformer delivers an ear-grabbing Hitsville-style flavor
- Helios 5011 inductor-based EQ boasts selectable LF and MF controls and a fixed 10kHz HF control
- Pre O/P control adds +10dB of gain to the unit's output stage for distorted preamp effects
- F760 FET compressor sports a custom transformer-balanced input and output
- Ratio, Attack, and Release Sec rotary switches dial in your compression behavior
- A setting deploys an auto dual-platform release function for the compressor
- Limit Only/Comp+Lim switch bypasses the compressor for limiter-only operation
- Analog meter indicates the amount of gain reduction from 0–20dB
- Deploys as a complete channel strip or as separate units with individual rear-panel inputs and outputs
- 2 units can be stereo-linked via CV connection
- High-quality ELMA gold-plated rotary switches, gold-plated toggle switches, and sealed conductive-plastic pots
