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H2 Audio

H2 Audio is the recreation of the classic Helios console circuits – sculpting the sound for so many classic recordings.

H2 Audio – let Helios shine again

A little bit of history – recording history!

It is not possible to talk about the Helios history without dropping some of the big names in music. Wait, it's not „some“, it's „many“: The Rolling Stones, The Beatles, Elton John, Led Zeppelin, Motörhead, Genesis, David Bowie, Bob Marley, Iggy Pop, Eagles, Queen, ELP, Jethro Tull, Procol Harum, Frank Zappa, AC/DC, King Crimson, The Who… ok, this list has to stop somewhere. Those and many other bands and artists recorded albums on a Helios console. The recording studio mainly associated with Helios is Olympic Studios in London, UK. This is because Dick Swettenham, founder of Helios, was the main developer of studio gear for Olympic – where the first Helios console ever was installed.

Bringing classic Helios sound into today's studios (and recordings)

H2 Audio was founded by Al Sutton, who is the founder of Rustbelt Studios and ACME Audio, Tim Mead, founder of Q2 Audio and recording engineer Perry Tell. Their aim was to revive the Helios heritage as good as possible and without any compromises. And yes, it worked.

Why is H2 Audio's name not Helios?

Having a look at the products, it is obvious H2 Audio recreates the much-adored Helios preamps and EQs. So why the name „H2 Audio“?

• Getting the international rights to use a name is everything but easy. The three men behind H2 Audio tried, but put their effort rather in creating non-compromising gear than in paperwork and legal matter. A good choice, if you ask us!

• H2 can be interpreted as „Helios, Version 2“.

• The name needed to have a positive connotation. And as „H2“ is one third of „H2O“, meaning water, it works perfectly.

• One of the founder also founded the audio company „Q2“, so „H2“ fits right in!

• They decided to show their first product at the NAMM show. So finding a name had to be a quick decision.

How many audio companies do you know using an electron microscope? Well, now at least one!

What do you do when you need to meticulously recreate a transformer that is out of production for decades? Of course you tear one apart and put it under the electron microscope. This actually has been done in Michigan University with the Lustraphone transformer being used in the old Helios consoles. It was crucial to know the exact metal alloy that has been used. We don't see this as a crazy obsession but as a token for the accuracy H2 Audio shows in getting as close to the original Helios as possible.

H2 Audio products

There are H2 products for both two standards: 19“/2U standalone units and modules for API's Series 500.




2128 500 series Preamp
5011 500 series Equalizer
Helios Channel 19’’ Twin Preamp + EQ
0011 Stereo 19’' Preamp, EQ, Compressor

How to use a Helios equalizer

Helios-style equalizers differ from the common EQ with it's usual standard set of controls. But it is not complicated at all: High is a fixed 10k-shelf, allowing +/-10 dB. Mid comes with stepped frequency and gain. A switch toggles between „PK“ and „TR“, meaning „peak“ (= boost) and trough (= cut). The bass band is either a bell with stepped frequencies or a 50Hz-shelf with stepped cuts. When using a Helios-style EQ for the first time, it might be a little confusing that the different bell frequencies and the different shelf gains are on the same rotary switch.

How does Helios/H2 sound?

There is one expression used frequently to describe the sonic character of the Helios preamp sound: „woody“. It does not sound as „snappy“ as an API and does not douse every signal with colourisation. The EQ, deriving from a console, is versatile and allows high gain settings without sounding unnatural. You don't need to knock on wood: H2 Audio managed to recreate the beloved Helios sound: The products carry recording heritage in every solder joint!

Helios were building large analog consoles. Are H2 going to follow?

Since the launch of their first Series 500 module, H2 Audio get asked if they will ever make a console. And yes, there is actually something in the making! So if you are interested in a high class analog console oozing out sonic character, contact us at KMR Germany.

H2 at a glance

  • recreation of classic Helios equipment
  • transferred to modern formats (Series 500, 19“)
  • Helios-style EQ, preamp and compressor available
  • no-compromise build quality
  • sound as close to the originals as can-be
  • Made in USA
  • H2 Audio 0011/Stereo

    H2 Audio 0011/Stereo

    This is a 2U 19” rack stereo pair of 0011s. All features of the 0011 included in a rugged steel constructed rack. The original channel module from so many iconic studio recordings of the past...

    €6,499.00 (Inc. Tax)
    €5,461.34 (Ex. Tax)
  • H2 Audio Helios Channel

    H2 Audio Helios Channel

    H2 Audio could not be more excited about the release of The Helios Channel. With the rise of home recording and hybrid recording methods we have created The Helios Channel, featuring the classic 0011...

    €6,599.00 (Inc. Tax)
    €5,545.38 (Ex. Tax)
  • Sale
    H2 Audio 2128 + 5011 Combo

    H2 Audio 2128 + 5011 Combo

    The ultimate H2 Audio Channelstrip comprising of both the 2128 Preamp and the 5011 Equalizer.

    Was: €2,799.00
    Now: €2,519.00 (Inc. Tax)
    Was: €2,352.10
    Now: €2,116.81 (Ex. Tax)
  • H2 Audio 5011 500-Series EQ H2 Audio 5011 500-Series EQ

    H2 Audio 5011 500-Series EQ

    The H2 Audio 5011 is a 500 series EQ and a faithful recreation of the legendary Helios mic pre and EQ found on the Helios console at Olympic studios. The H2 Audio 5011 is a 3-band EQ with a...

    €1,519.00 (Inc. Tax)
    €1,276.47 (Ex. Tax)
  • Sale
    H2 Audio 2128 500-Series mic pre H2 Audio 2128 500-Series mic pre

    H2 Audio 2128 500-Series mic pre

    The H2 Audio 2128 is a 500 series mic preamp based on the iconic Helios found on the Helios console at Olympic studios. The H2 Audio 2128 delivers up to 70dB of gain and includes all the...

    Was: €1,399.00
    Now: €1,259.00 (Inc. Tax)
    Was: €1,175.63
    Now: €1,057.98 (Ex. Tax)