Product Review - Magenta ADE-24: "The Black Box" Analog Digital Enhancer - October, 1999

Paul Knutson


ADE-24 Analog Digital Enhancer

MFR: 15 Hz - 20 kHz

THD: 1.5%

Size: 3 1/2" H x  5 1/2" W x 8 1/2" D 

Weight: 2 1/2 Pounds

MSRP: $250 USA

Margules Audio; E-Mail [email protected]; Web  

There are two schools of thought, residing at opposite ends of the spectrum, about the best way to assemble a high-definition stereo: 

School #1 - The Purist

Motto:  Keep the signal path clear of anything that changes the signal -- the signal from your source can only be damaged and never improved.

System characteristics may include the following:

  •         No tone controls

  •         Short interconnects and speaker wire

  •         Absolute minimum capacitors and resistors in the signal path

  •         Short, point-to-point wiring inside components - no Printed Circuit Boards (PCBs)

  •         No signal processors or equalizers

  •         No global negative feedback in amplifier or preamplifier

  •         Passive preamplifier

School #2 - The Traditionalist

Motto:  Since recordings and playback systems aren't perfect, and since my ears don't always agree with those of the recording engineer, I prefer to make my music sound more the way I like, using whatever technology is available to me.

System characteristics may include the following:

  •         Bass and treble tone controls

  •         Full-function preamps built with PCBs if necessary

  •         Multiple-octave equalizer

  •         Digital or surround sound signal processor

  •         High-feedback amplifier or preamp to reduce measured distortion

Obviously these examples are exaggerated to make a point, but you get the idea.  In audio, like everything else, we have different strokes for different folks.  Personally, I fall closer to School #1, The Purist camp, but I try not to obsess about it.  Truth be told, because I build a lot of my own equipment, and because I don't know how to build anything complicated, my system may be purist by default.

So how does this introduction lead into a review of the Magenta ADE-24?  The ADE-24 nicknames itself "The Black Box".  In the world of high-end audio, a "black box" is a generic term for a component that is inserted into the signal path at some point typically after the output of the digital signal and before the preamp, or after the preamp and before the power amp.  In each case, the purpose of these "black boxes" is to 1) somehow electrically alter the signal being passed through it; and/or 2) provide a better electrical conduit (in term of impedance matching) from Component A to Component B.  Along those lines, a "black box" of any type is generally of more interest to Traditionalists than Purists.

Input/Output impedance optimization is always a good idea.  Mismatched impedance between components can rob music of its life-like essence and contribute to all types of frequency response aberrations, manifesting audibly in high-frequency harshness or mid-bass dropouts, among other sonic nasties.   So if the ADE-24 contributes to solving this common problem, chalk one up under the column of "positives" on the audio blackboard.  The other function of a "black box", being the alteration or "enhancement" of the musical signal, is harder to assess.  Altering the signal is typically a no-no in high-end audio, but this presumes that everything coming out of your CD player or outboard DAC is right to begin with -- and don't you just wish that were the case!  An exact description of what happens from input to output in the ADE-24 was not available, so listening to the ADE-24 was really the only way to judge its effectiveness toward the goal of "enhancing" the musical signal.  Plus, the ADE-24 is not meant to be disassembled, examined or tweaked, so I just kept my curiosity to myself.  I admit, my do-it-yourself tendencies make we want to have a look under the hood of every audio component that comes through my door, but in this case the lid stayed shut. Actually, this is what a black box is, namely something that is useful, but you you don't really know what is inside.

The Magenta (by Margules Audio) ADE-24 is relatively inexpensive at $250, but even at that price, value is hard to assign.  This is, after all, a little black box with only one set of inputs, one set of outputs, a power cord and a single, green LED.  It feels well built, and it's a nice-looking little bugger, but beyond that there isn't much to it functionally.  If you have $250 to spend, you can do lots of things to improve the sound of your system -- upgrade your cables, accessorize with isolation feet, upgrade your DAC or CD player (albeit modestly at that price), or work on improving your listening room.  With so many options, why spend the $250 on an ADE-24?  Because this baby really works, that's why.

The Magenta division of Margules Audio (both companies are based in Mexico) includes a lineup of products that are less expensive than the Margules primary lineup, but still technically impressive.  Magenta is an attempt to reach an even more broad customer base than Margules' already affordable lineup of world-class components.  I have heard Margules Audio's stunning tube-based equipment and loudspeakers at a couple of high-end shows, and that they are dropping down into even more affordable territory with the Magenta lineup is good news indeed for all value-conscious audiophiles.  Julian Margules, the company's namesake, is in step with the needs of all audiophiles, not just those that happen to be founders of .com companies.

Operating the ADE-24 is simple.  It should be inserted between any digital (not analog phono) audio source and a preamplifier or amplifier.  I know what you are thinking -- here comes the next lame reviewer joke poking fun at the early 80s digital audio ad campaign of "Perfect Sound Forever".  Nope, I vow from here forward to never again beat that dead horse of a joke.  Should I break that promise, feel free to lock me in a room and force me to endure any Kenny G release on repeat mode for 48 hours straight -- that will teach me a lesson!  Let's simply agree on the fact that some listeners, even with today's improved digital playback technology (and even better on the horizon), remain unsatisfied with the sound of CDs.  Many, if not all of you, know exactly what I'm talking about.  This is especially true if the retail price tags of your digital playback gear do not hit the four-figure range, and that includes most of you reading this.  For all of you, the ADE-24 is Magenta's best offering of a real sonic solution.

The technology behind the ADE-24 focuses on fixing sound in the analog domain, not the digital domain.  Attacking the digital domain would require more bucks than the $250 outlay that Magenta is asking for the ADE-24.  Quoting directly from the Magenta product information, this is their explanation of how the ADE-24 works:

"The design of the ADE-24 is based on the idea that high-order odd harmonics are generated during the reconstruction of the analog signal. These harmonics falsify instrumental timbre, and create a bright, hard, or harsh sound. We designed a circuit with the reverse transfer function, to remove these unwanted harmonics and more-closely approximate the original signal. Implementing this design would normally require integrated circuits (with less-than-perfect sound quality), or costly discrete circuits. Our original circuit topology (patent pending) gives outstanding performance at a reasonable price. The ADE-24 is also a buffer. Its low output impedance reduces interaction between the program source and the interconnecting cables. The ADE-24 is connected to the output of any digital audio source:


∑ CD
∑ Laserdisc
∑ D/A converter
∑ AC-3 (Dolby Digital) and DTS
∑ Computer multimedia


It (ADE-24) substantially improves the sound quality of any digital source, narrowing the gap with more-expensive equipment. This isnít "magic"óitís the product of research in electronics and psychoacoustics."

I listened to the ADE-24 in both my home reference system and my office system for a few months each.  In both systems, especially with my solid state-based office system, the ADE-24 generally performed as promised.  Digital sound became warmer, richer, and overall less objectionable, especially on poorer recordings.  There was a clearly audible increase in the sense of harmonic richness and bloom to the primary instrument in chamber music, especially cellos, violin and other stringed instruments, that proved absolutely intoxicating.  Bass reproduction became a bit bigger, for lack of a better description -- not bloated in a "Boom-Boom" car audio sort of way, just bigger.  With vocals, the singer seemed to move slightly forward in the soundstage and take on a larger presence within the recording.  It was as if the recordings were re-mixed, not in a bad way, just different from what I was used to.  This increased vocal prominence was especially true with male voices, notably those with rich baritones like Johnny Hartman or Frank, "The Voice".

With the ADE-24 installed, the resolution of detail and musical nuance did not seem to suffer, which is always a concern when you insert anything additional into the signal path.  This is particularly true of the ADE-24's performance in my office system where there was zero perceptible decrease in resolution.  I did feel that in my single-ended triode, tube-based home reference system, which is highly revealing, the ADE-24 imparted a mild sense of "being there".  In other words, beyond the changes in tonality and soundstage perspective, I could tell from a resolution of detail standpoint that the ADE-24 was in the circuit.  It sounded like a slight obfuscation of detail, an extremely minor rounding of certain percussive strikes for instance.  I should emphasize, however, that this wasn't a big deal, but the audio reviewer in me is compelled to point it out.

Remember, the resolution change I heard in my reference system is also partially attributable to the insertion of another pair of interconnects into the signal path.  That's an unavoidable part of using the ADE-24.  Interconnects, more specifically their RCA connectors, are notorious for adding their own signature to the playback chain.  However, despite the resolution issue, at no point did I feel like music was losing its essential character with the ADE-24 inserted -- far from it.

To review equipment accurately (who? me?), especially front-end components, I need to be able to hear whatever a component is doing, warts and all.  On my reference system, the ADE-24 has the effect of making different front end CD playback systems sound more similar than not.  The sound was uniformly good when I tried different CD players or transport/DAC combos, but again, there was some homogenization.  This is good for most of you reading this because you don't need to listen critically to a variety of components and write about what you hear.  For me, this doesn't work as well, but that takes nothing away from the sound of the ADE-24 in circuit, which as reported was very good.

Using the ADE-24 did not exactly make my digital system sound analog -- that's asking a little too much of an affordable accessory.  What originally attracted me to the ADE-24 was some wildly positive comments about it's sound from a formerly analog-only audiophile whose ears I trust.  When that happens, it's best to take note.  Truth be told, as expected, the only way to get true analog sound is to play vinyl records, which I love to do, but for the sake of convenience don't do that often.  While the ADE-24 didn't magically transform digital sound to analog, what it did do was allow affordable digital playback to take on more of the positive sonic characteristics of good analog playback -- the warmth, tonal beauty and naturalness that analog does so well.  In that sense, using the ADE-24 was like having your cake and eating it too -- you can keep your affordable digital equipment for the time being and be happier listening to it.

In my office system, where the ADE-24 has found a comfortable and loving home, I have alternated between having the ADE-24 in the system for a couple weeks, then removing it for the next couple.  My goal is to establish general impressions about my enjoyment of CD playback in each scenario without the type of focused, "reviewer-mode" listening that I do on occasion at home.  In the office, I hear the music clearly, but my listening perspective is not that of a reviewer, per se.  What I've found over the past few months is that when the ADE-24 is in the system, I am definitely enjoying the music more.  It truly isn't any more complicated than that.  It's an almost subconscious thing, really, but there's no question that CD playback sounds more like real music in my office system when the ADE-24 is doing its thing.

Here are some tips for getting the most out of the ADE-24: First, keep it on all the time, which is both how it was designed and certainly how it sounds best.  There is no on/off switch, folks, and there's a reason for that.  The ADE-24 doesn't use much power, and it sounds a heck of a lot better when it's been on for at least 24 hours continuously.  I found this out the hard way during my reviewing.  The first couple times I had it in and out of the system for a simple A/B comparision, I was too quick to judge the sound upon re-insertion into the system.  I would take some listening notes that weren't so positive only to have those impressions nullified after the ADE-24 was up and running for a day or two.  Then, the sound of the ADE-24 was much better and more representative of its true capabilities.  My second insider hint is to try the non-detachable 2-prong power cord inserted into your power socket in both directions -- you may be surprised.  The prongs aren't polarized, so the cord will fit into the power socket either direction.  There isn't a right or wrong way to plug in the ADE-24, just the way that sounds best in your system.  Try it both ways and listen.  This is the old polarity issue -- it is very real and very audible.

As many of us take a wait-and-see approach to the jumbled format wars of the pending digital audio playback standard, we must in the meantime live with what we have -- good old 44 kHz/16 bit digital audio playback.  Personally, I'm not holding my breath for the new digital standard.  Sure, I'm looking forward to it, but realistic timeframes should be measured in years, not months, until everything is sorted out and new software is available.  Until then, for those of you who want something more from your affordable digital playback system, and for those who prefer a digital sound that is altogether more listenable, I strongly suggest you contact Margules Audio and ask them how you can get your hands on an ADE-24.  As I said earlier, this is one little Black Box that works.

- Paul Knutson -

© Copyright 1999 Secrets of Home Theater & High Fidelity
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