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Positive Feedback ISSUE 1
june/july 2002



Passive Digital Antidote Two

as reviewed by Greg Ewing


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Magneppan MMGs and two 12-inch Audio Concepts subwoofers in spiked sealed enclosures.

Monarchy Audio SM-70 monoblock amplifiers (on Maggies), Audire Crescendo amplifier (driving subs), Audio Control Richter Scale III 24 dB/octave electronic crossover (set at 72 Hz, low pass only), and an Antique Sound Lab AQ2004 tube preamplifier.

JVC XL-Z1050TN (highly modified) CD player and an Adcom GTP-350 tuner.

Canare Star Quad interconnects and Kimber 4PR speaker cables.

Taddeo Digital Antidote (latest passive version), AudioQuest RF Stoppers, Bright Star Audio IsoNode isolation feet, marble platforms, Blutak, Cascade Audio Engineering room treatments, and an Elfix Polarity Tester.


Taddeo's Digital Antidote products have been around for several years. Both the active version ($995) and the passive version ($99.95) incorporate Taddeo's proprietary phase-altering technology to enhance the digital audio experience. They both work in the analog domain, and are inserted between a CD player or DAC and preamp. The Taddeo web site explains that "The Digital Antidote will correct for the phase errors inherent in all CD players and DACs as a result of the proverbial steep ‘brick-wall’ filter in 44.1kHz digital processing. The heart of the problem is that a ‘brick-wall’ filter, be it analog or digital, will result in phase distortion. Oversampling will not solve the problem. Oversampling puts the anti-aliasing filters at a high enough frequency to be rendered benign, but because the information stops at 44.1kHz, the information itself forms a ‘brick-wall’ filter." This explanation makes sense to me, and provides further evidence of the hard reality that the digital technology of the early eighties was not quite perfect sound forever, and is a format with technical and sonic limitations.

The patented Digital Antidote circuitry takes the analog output signal and divides it into two equal branches. One branch is delayed approximately 16 microseconds, and the other is then summed with the delayed branch. This apparently cuts the phase error dramatically as well as increasing the amplitude resolution. Another side effect of this is a gentle rolloff starting around 15kHz. I wouldn't call a rolloff of a dB or two from 15kHz up a huge problem for your average 16/44 CD player. Most of us can't hear frequencies that high, and what digital does render in that range sounds pretty sterile anyway. However, don't get the impression that the Digital Antidote is just a low pass filter. Merely inserting a black-box EQ that tames the highs of a digital rig would fall woefully short of the sonic benefits that the Digital Antidote provides.

I tried the Taddeo with my highly modified JVC XL-Z1050TN, a JVC + Bel Canto DAC, the Rega Jupiter 2000, and even a Sony Discman. The most obvious improvement that the Digital Antidote renders is the fleshing out of cymbals and percussive sounds. On CD after CD, cymbals went from sounding like a drum machine to sounding like real cymbals with 360 degrees of surrounding air. In addition to transforming percussive sounds, there is less of the digital edge that most people (even non-audiophiles) can easily hear but find difficult to describe. The Digital Antidote removes a substantial portion of that digital edge, and thus greatly reduces the listener fatigue that is so prevalent in 16/44 digital. While listening to Steve Hackett's live acoustic There are many sides to the night CD, I was struck by how much more relaxed and the nylon classical guitar sounded in its decay. In addition, the clapping of the audience sounded much more like real handclaps, not at all metallic sounding as it does on so many live CDs. On Gustavo Santaollala's stunning Ronroco CD, the charango and guitar on sounded much more natural, with more space around them as well as more air within the overall soundstage. Dense and complex musical passages sounded less congested. I didn't notice any sonic changes below the midrange, though. The remastered Roxy Music Avalon CD contains a wealth of slick production, and the Digital Antidote brought this listener one small step closer to the studio. The music became more involving, a pretty good feat for a $99 product.

The most surprising thing of all was the improvement the Digital Antidote wrought upon the Sony Discman. I had never played this portable CD player through my system, but the effect of the Digital Antidote was so noticeable on the other players that I decided to give it a try. The Discman sounds so incredibly bright that I use its bass boost feature with my Grado headphones. With the Digital Antidote, however, the Sony produced almost-respectable sound. I can imagine many cheapskate audiophiles using a cheap CD player hooked up to the Digital Antidote and getting decent digital sound for a few hundred bucks. Note that the magnitude of the improvement seemed to lessen as I went from the Discman to the JVC to the Bel Canto DAC, and finally to the Rega Jupiter. Yes, it slightly tamed the Jupiter’s high end, but I didn't hear dramatic improvements elsewhere. Unfortunately, I didn't have any SACD players in house, so was unable to test Taddeo’s claim that the Digital Antidote can also improve SACD. I would be surprised if this were the case. In my limited SACD listening experience, I hear little or none of the phase distortion byproducts that are blatantly obvious in 16/44 digital.

From my brief evaluations of the active Digital Antidote as well as the passive one, I believe that the passive version has a slightly more obvious top end rolloff, though as stated earlier, I don't think too many audiophiles will mind this. The active unit also sounds more transparent in the midrange and top end. The great thing about the passive version is that it does not require an additional set of interconnects. The downside is that it uses very inexpensive captive RCA connectors and cables. I plan to disassemble the unit and upgrade it with Canare Star Quad interconnects.

Of all the tweaks over the years that have promised to make digital sound more analog-like, this is one that is worth your time and money. When first installed in your system, the Digital Antidote doesn’t sound that dramatic, but after living with it for a number of days or weeks, removing it will certainly have a very dramatic effect on the sound of a good system. With a 30-day free trial, you have little to lose but digital glare and edgy sound. Greg Ewing




Taddeo Passive Digital Antidote Two
Retail $99.95 factory direct w/30-day free trial

Taddeo Loudspeaker Company
TEL: 716. 473. 9076
web address: