H2
0011 Mic Pre and 3-Band EQ
0011 Mic Pre and 3-Band EQ
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11- Series Helios Style Mic Pre and EQ
The H2 Audio 0011 Mic Pre & 3-Band EQ delivers that unmistakable Helios punch — open highs, tight lows, and lightning-fast attack — backed by massive headroom and creamy transformer warmth. Built like the originals, with refinements for today’s modern studio workflow.
Step into the control room from the golden era of rock & roll. The H2 Audio 0011 captures the exact tone and feel of the legendary Helios production modules that shaped countless ‘70s classic hits. Every note comes alive with transient snap, rich harmonic depth, and a musical EQ that shapes without smearing.
The Most Iconic Mic Pre from the 70’s Golden Era
From the Lustraphone M10 input transformer to custom-wound inductors and gold-plated ELMA switches, every part is engineered for the purest signal path. With 32V rails for massive headroom, the 0011 delivers pristine clarity when you want it and thick, saturated character when you push it.
This isn’t just a reissue. It’s Helios DNA, refined for the modern recording landscape.
Legendary Helios Tone, Modern Studio Ready
- Legendary Helios tone — punchy, open, and alive
- 25–75dB mic gain via Lustraphone M10 input transformer
- Custom inductor-based LF/MF EQ + fixed 10kHz shelf
- Transformer-balanced output with 600Ω drive up to 25dBm
- Gold-plated ELMA rotary switches & conductive plastic pots
- Fits 0011 Series racks: H2 Audio 002, 004, and 008 rack
H2 Audio '0011' spec
The H2 Audio 0011 faithfully recreates the iconic Helios mic preamp and EQ with precision upgrades:
- Mic/Line Input: Lustraphone M10 input transformer delivers 20dB mic gain before the preamp. Selectable Line, Mic, or Mic with 20dB pad.
- Gain Control: 25–75dB gain in 5dB increments.
- EQ Section: Custom-wound inductor-based LF/MF EQ with selectable LF (60, 100, 200, 300Hz boost) and MF (0.7–6kHz boost/cut), fixed 10kHz HF, and variable 50Hz high-pass filter.
- Switches: Gold-plated ELMA rotary switches and conductive plastic pots, sealed for longevity.
- Output Stage: Transformer-balanced line out, original Helios design, 600Ω drive up to 25dBm before clipping.
- Power: Runs on H2 Audio 002, 004, or 008 racks
Bring Helios into your signal chain.
From vocals and drums to guitar and bass, the 0011 Mic Pre & 3-Band EQ gives you that unmistakable rock authority with the control you need for modern production.
-Gold plated audio toggle switches
-High-quality, ELMA gold plated rotary switches.
-Sealed, conductive plastic element pots
Technical Specs
Technical Specs
Rotary switches are all high-quality ELMA gold switches.
-Toggle switches for audio are all gold plated.
-Pots are all conductive plastic elements, sealed.
-Power rail is 32V giving higher output before clipping vs the original Helios 0011.
0011 Mic-Preamp:
Lustraphone M10 input transformer providing 20dB of mic gain before the preamp.
Preamp:
LINE/MIC/MIC -20 (20dB pad) toggle switch: selects input source 'line', 'mic' or 'mic' with ~20dB pad.
Mic Gain rotary switch: 25 to 75dB of gain in 5dB increments.
Line input: electronically balanced.
EQ:
Custom wound inductor based LF/MF EQ section with selectable LF and MF and fixed 10kHz HF controls.
10kHz rotary switch: +/- 10dB boost/cut in 2dB steps.
MID GAIN knob: controls amount of mid boost or cut selected by PK/TR switch.
PK/TR switch: selects mid EQ to be 'peak' (boost) or 'trough' (cut).
MID kHz rotary switch: selectable frequencies for boost/cut: 0.7, 1, 1.4, 2, 2.8, 3.5, 4.5 and 6 kHz.
LF BOOST knob: controls amount of LF boost selected by BASS HZ switch.
BASS Hz EQ rotary switch: selectable 60, 100, 200, 300 Hz boost, or variable 50Hz filter with selectable 3, 6, 9, 12 and 15dB cut.
EQ CUT toggle switch: EQ cut in down position.
PHASE switch: inverts polarity of output signal after output transformer.
FILTER toggle switch: 0, 40 and 80Hz roll off.
To the original 0011 circuit, H2 Audio has added a transformer balanced line output amplifier of original Helios design. 600 ohm drive capability up to 25dBm before clipping. Custom output transformer.
Analog I/O connections:
All I/O connections are on a 32-way edge connector that mates with either the 002 ( two channel) or 008 (eight channel) H2 Audio racks.
Mechanical:
Height: 7” (4U)
Width: 1.7”
Power source:
Power is provided by either the 002, 004 or 008 rack
- Gold Plated Switches & Toggles
Hand Assembled in DETROIT
Custom Transformer
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"I turned the knob and bam! There it was. ...I miss that"
Eddie Kramer- Legendary audio engineer & record producer, (Led Zeppelin, Jimi Hendrix, Rolling Stones, Kiss )
A Helios Classic for Every Type of Studio
At H2 Audio, we build premium audio pieces that inspire. Explore our full range of reimagined classics, re-engineered for the modern studio. Rackmounts, Channel Strips, 500 Series, and our flagship Mic Pre's and Compressors, all built with precision craftsmanship and modeled after the original Helios units from Olympic Sound, London.

