IX1   Inline Audio Input Transformer (patent pending)
Hey, I need some art up in here!
  • Exact same input transformer as the classic Neve 1073 mic preamps (Lundahl LL1538)
  • Passes Phantom Power (No Batteries required)
  • High Quality Neutrik connectors
  • Combo Input Jack allows XLR or 1/4" balanced or unbalanced inputs
  • Adds classic character to virtually any existing microphone preamp including:
    • Tube
    • Solid State
    • Op-Amp
    • Discrete Component
  • Breaks ground loops reducing noise
  • Convenient height: 1 Rack Unit
  • No "lunch box" or extra equipment required
  • Black enclosure makes it perfect in a stage setting. Use it in recoring studio or in a live setting
  • Rugged, Stainless Steel box electrostatically shields electronics
  • Low price
  • Perfect for musicians and voice performers
  • Handles small or large inputs (like brass instruments). Virtually any voice or instrument.
  • Made (except for Swedish transformers!) in USA.

Most of us don't have the kind of money laying around to go out and upgrade all of our mic preamps to say... a Neve 1073. My name is Jeff Shadley and I certainly fall in that category. If you are like me, you might have wondered what the difference between a "project" studio and a "professional" studio is; or maybe if there even is a difference. My bachelor's degree is in Trumpet Performance and my Master's degree is in Electrical Engineering so I thought I might be just the right guy to figure out what really matters in the professional studio and what isn't so critical. Several decades ago, I set out to do just that. Until a couple of years ago, I have to say, my mission was a frustrating one.

Clearly there are many factors that make a professional studio sound great but some factors are really important and others might make the studio sound different but not necessarily better or worse; just different. Some things are fairly inexpensive to try; well within the reach of a guy like me with a day gig and a family. I tried all sorts of things to improve the sound of my studio.

  • Acoustics
  • Equalization
  • Microphones
  • Tape Saturation
  • Gear Emulators
  • Compressors
  • Discrete Components
  • Op Amps
  • Mastering
  • etc..
To be sure, all of the above are critical pieces in the creation of a hit record. And yet, the sound I was looking for remained elusive. I knew the sound when I heard it, but I just didn't know how to create it.

All the equipment I was using had better specifications than the equipment of yesteryear and yet somehow, unlike me, the engineers of old managed to make records that sounded real. Even as I accepted that the truly great engineers are simply more talented than I am, I felt I should at least be able to identify what they were doing that made their sound so great.

After decades of trial and error (mostly error!), what I found is that if I configure transformers in the same way as the great classic gear of yesteryear, my studio sounds suddenly has that great, real sound. I don't know how to explain it. I just, suddenly sounds "amazing". All of the things I used to make sure I got just right, don't seem to matter quite as much as they did. As long as I get the transformers right, everything sounds amazing. If I make a mistake, it often still sounds good.

A tiny slice of recording studio history

Throughout most of the '60s recording studios had a vertical model. Highly specialized audio engineers designed custom recording equipment specifically for them. EMI studio in London (which became Abby Road Studio) designed their own highly successful microphone preamps which today we refer to as the "Dark Side of The Moon" (DSoTM) preamp. It was these mic pre's that Alan Parsons used to such great effect in recording the classic Pink Floyd albums. Likewise, in New York, Columbia's 52nd Street studio engineers used mic preamps that would record some my favorite Chicago albums in the early '70s. The 52nd Street studio had been a radio broadcast facility previously. The microphone preamp designs were of necessity fashioned after radio gear from the previous decades. And so it was that the gear that recorded the most successful music of the 60's and 70's was directly descended from the gear that broadcast news of World War II only a few decades previous. Psychologically and culturally, we listeners learned that really significant audio has a certain quality to it. Conversely, Audio that did not have this particular quality gets dismissed (by the brain) as insignificant.

Audio designs during the early days of radio relied on transformers and tubes. Unlike the inexpensive, high-impedance op-amps with countless transistors and swamped with feedback that we enjoy today, these early designs had limited gain and headroom and fixed impedences. Transformers were used to match impedances between various stages of the audio signal. In the case of a microphone, a transformer would typically be used to trade some current for a little extra voltage.

The vertical studio model of the '60s and early '70s was expensive. Each successful studio invented, manufactured and maintained their own proprietary gear relying on the experience and acumen of their engineering staff to guarantee the design would produce hit records. Meahwhile, a new integration model for studios was unfolding in the early '70s. Rupert Neve felt that his company could design a mixing console with built-in solid state preamps and sell the console to any number of studios. Neve did just that. Countless hit records were recorded on the Neve 80-series consoles. Rupert Neve's designs of this era used silicon instead of tubes because his customers were demanding features that simply would not fit in a tube-based design. Neve used transistors with the lowest noise floor he could find but the complexity (active device count) of the circuit was little more complex than its tube-based predecessor. Here as before, transformers were used to adapt input and output impedances of the class 'A' (pre)amplifiers but they were also used for another purpose. Neve knew that to successfully decouple the various components of his design from common-mode noise, the transformer was the perfect vehicle. Each component in the design of Neve's famous 80-series consoles had an input transformer and an output transformer. By the time the music made it out of the studio an onto a two-track tape for mastering, it had been through countless transformers. Each time, the energy was converted from voltage-current energy to magnetic energy inside the core of the transformer and then back to a slightly different voltage-current ratio. The music on these hit records at one time existed in the tiny magnetic dipoles in the mu-metal core of these transformers.

By all accounts, Rupert Neve worked very closely with manufacturers to create the perfect transformer(s) to his specification. Frequency response, rise-time, over-shoot, droop, saturation all met his criteria. The result of this collaboration is the Lundahl LL1538; perhaps the most famous and most highly regarded microphone input transformer of all time. The simple reason Lundahl transformers do not appear in "project" studios is the labor required to manufacture them. Unlike circuit boards which can be rolled and stuffed by machine, only limited automation can be used in the manufacure of these transformers.

Every transformer has its limitations and tradeoffs. These tradeoffs were carefully evaluated by Neve himself. If there is a practical limitation of the Lundahl LL1538 it is the lack of a centertap on the secondary coils. This surprising omission makes it difficult to pass common-mode current through the device (needed to supply phantom power to upstream microphones). The (patent pending) design of the IL1 works around this issue by placing a second transformer in parallel to the secondary of the LL1538. No audio passes through the second transformer. This artifact of the design is critial to maintaining the faithfulness of the LL1538's characteristic sound. Only common-mode phantom power goes through the second transformer. The differential signal is blocked by the 1M resistor on the primaries of the second transformer.


Exactly what effect the Luhdahl LL1538 has on the audio energy that passes through its core is unclear. The patent application does not address this aspect of the design. It is sufficient to know that something about the performance of this marvelous transformer imparts one or more classic effects onto the audio.

You can use the IX1 in-line with a mic. You can run line-level signals through the IX1. (Just be aware there will be some voltage gain as you go through the device.) The IX1 is rugged enough for use in live settings. It's satin black color even allows it to blend into the stage. In a recording environment, you can pass your signal through the IX1 multiple times to get even more classic audio effect. You are not stuck with only one sound. If you choose, you can swap the IX1 in and out of your input chain. Now, for the first time, you can put this magical transformer in front of any preamp you want. I particularly like the way it sounds with a tube preamp!

Perhaps the best thing about the IX1 however is the fact that you can buy just 1 to build a single super channel. Then when you are ready, buy a second to support stereo, three channels and so-on until you have enough channels to do complex tracking sessions.

I'm very proud to present the IX1 to the world. Too many musicians and voice artists are barred from entry into the music buisness - not from lack of talent - but rather from access to the kind of equipment that watermarks their music as "significant". The IX1 will blur the sonic distinction between industry giants and emerging artists who deserve to be heard.

  Users Guide for IX1