Thursday, August 16, 2012

The McIntosh MI3 Performance Indicator

For those who are interested in high end audio, the name McIntosh is synonymous with perfection.  McIntosh, for those less educated in the realm of audio, is more or less the Mercedes-Benz of audio equipment.  McIntosh Laboratories, has for years, maintained a classical interpretation of what constitutes high fidelity sound.  The company has chosen to maintain an allegiance to vacuum tube driven units, arguably one of the most elegant and beautiful ways to produce high quality sound.  

Vacuum tube driven audio has become almost completely obsolete from modern audio equipment and is maintained only by a handful of companies.  Most audiophiles lean towards this anachronistic method of driving audio because of the signature quality that only tubes can produce.  Vacuum tube audio systems, by their very design, introduce distortion into the audio signal.  This would typically be frowned upon, but the distortion present in tube-driven units is particularly harmonic to the human ear and thus often preferred by audio aficionados. 
I very recently acquired a vintage McIntosh product that I am extremely proud of.  This particular unit was introduced in 1964 and is known as the MI3 Maximum Performance Indicator.  The MI3 is extremely rare today in the sense that the technology utilized within the unit is completely obsolete and that the instrument itself is difficult to track down given its age and the specific nature of its utility.  The MI3 is a passive instrument, which is to say it does not affect the audio signal that is subject to.  Rather, the MI3 is an audio-testing unit; designed to visually represent an audio signal.  The MI3 achieves this objective via the use of a cathode ray tube, which is in turn driven by vacuum tube technology.  When all the shiny paper and complicated descriptions are pealed away, the MI3 is an oscilloscope, no more & no less.  The instrument allows the user access to a variety of different features, most notably the ability to monitor and thus reduce multipath.  The MI3 was designed to be used in conjunction with a tuner; allowing one to tune more accurately and be aware of the presence or lack of multipath.  The MI3 is also capable of displaying reversed polarities, out of balance audio sources, & missing channels.  When a source is accurate in its representation of a stereo signal, the screen of the MI3 is filled with dancing glowing lights, a beautiful and chaotic interpretation of the present audio signal.

While the MI3's usefulness in acquiring top-end audio clarity is minimal at best (especially the tuning utility), itself and units like it have become collectable for their use of cathode ray tubes.  The technology is beautiful and just plain cool to look at.  The build quality of the MI3 is top notch, as would be expected with any McIntosh product.  The use of black glass and anodized gold font beautifully dates the unit, as do the silver pots.  

The McIntosh MI3 Performance Indicator is two things: a rare and elegant electronic instrument produced by one of the most respectable audio houses in the world & quite literally, a visual and design-based representation of 1960s technology.            


  1. Hiya! It is April, 2014 today. I remember reading this post about a year ago. I have known about the McIntosh Maximum Performance Indicators for a decade. The moment I had first seen a grainy, black & white picture of one, I knew that one day I would own one. That day is today! Well, technically I own an MI-3 however do not have it in my possession; it's being shipped. (Yes, I am biting off my claws with anxiety as McIntosh makes the glass for just about every unit they ever produced except this model. That's how rare they are.)
    This is a delightful post and describes McIntosh's second version of a dolled-up Oscilloscope nicely. I don't like to admit it, either, that it is not a particularly useful instrument, as far a real-time measurements are concerned. It does give the trained eye a "window" into the world of signals that are the pulse of your great sounding Stereophonic Audio Sound System. I'll have the MI-3 on one rack for the McIntosh Tube Tuners and PreAmplifiers (or at least the McIntosh models that have Solid Aluminum knobs). An MPI-4 for the rest of the McIntosh Solid State kit (or at least the more 'modern' McIntosh models with the black-centered knobs).
    McIntosh gear operates as well or better than it looks and I see no reason why their Maximum Performance Indicators should be any different. =^.^=

    1. UpDate:
      Hiya! (again). It's May, 2014 and a McIntosh MI-3 is in a rack with about twenty of it's cousins (all similar-in-appearance McIntosh model Tuners, Pre-Amps, Amplifiers) and definitely is an Indicator of Maximum Performance! McIntosh Amplifiers have Blue colored illuminated Meters that are referred to as "eye candy". These analog meters move and bounce to the right, indicating power output in watts or db, depending on models. There are many McIntosh Amplifiers that do not have these meters at all and are essentially the same amplifier as any sister model that would have them. I will attest that the Power Amplifiers with the meters are more fun, as they show that the amplifier is doing something; (not that one couldn't hear that the amplifier is doing something :)
      The McIntosh "Green" is the lettering and design that glows when the Black Glass-Faced models light up. With the MI-3, the Electron Beam dancing on the green phosphorus cathode ray tube display is like watching a mesmerizing,1980's computer-green, 3-D campfire in sync with your music; on a tv set from the 1940's (or whatever era a tv set was 3 inches round).
      I have mentioned this to some folks: Being in front of all this equipment when I'm listening to something, I tend to, and like to, just "watch" this wall of gear. Similar to the way folks used to gather around in front of their big AM or Shortwave radios in the 1930's & '40's, while there was news or radio-play programs airing and would "watch the Radio". With the McIntosh MI-3 Maximum Performance Indicator, there is that much more of my "program" to watch.
      So: move over Blue Meters, I'm seeing Green.

  2. Anyone know of a source for push buttons for an MPI-4?