The TDS True Dimensional Sound Enhancer


Put on your 3-D glasses'

Clement Perry

1 November 1998


Passive audiophile full range sound enhancer
Price (US retail): $395.00
Dimensions (w × h × d): 7" × 2" × 7"

LOOKING through one of those CD mags I always seem to get each month, I happened to see an ad for a small box that promised miracles for only $199. Above the photo written in bold type was: "Closest thing to the live event." I laughed out loud, actually a bellow if you must know. This claim reminded me of why I enjoyed reading Mad magazine as a kid. I gave the company a call to see if Alfred E. Numan would answer the phone. Instead, an affable young gentleman named Chris Knecht, their VP of Marketing, gave me the scoop. He began reciting a litany of movies mastered with the TDS unit, and the recording studios who are also using the device. Discovery Magazine awarded them kudos, even. "Is that right?" was all I could manage to say. I admit, he impressed me more than Alfred E. Numan would have, but I still had that photo in my hand.... I am a true blue audiophile (translated: royal skeptic), so I immediately ordered one. Poor Chris hadn't dealt with my type before, I could only think of Batman's arch rival, The Joker, and his famous line: "Wait until they get a load of me!"

A few days later the unit arrived, but I'll admit that I was in no great hurry to hook it up. After all, I was mired in a review that had to be finished first and my system was smoking.

Let me go on record and state right here and now that many of my friends consider my system to be one of the most musically involving they've heard, period. A true no-holds-barred setup with a price to match. It's composed of some of the finest products, including Albert Von Schweikert's VR-6 speaker system ($12,500/pr, see review in the last issue); Riccardo Kron's (the man with the big brain) KR Enterprises VT800 mono block amplifiers using a new type of hybrid vacuum tube transistor (yes, that's right, a solid state tube) with 80 watts of pure Class A single ended power ($20,000/pr). digital is by way of Ed Meitner's superb killer combo of DAC and transport which goes for only $1,800; (and for me, I've heard nothing that sounds better, regardless of price) The preamp is the excellent Z-Systems RDP-1 digital preamp with equalizer ($5,000); the cables were the excellent Custom House Barracuda series (see review elsewhere in this issue). Power cords were the Electra Glide Reference Glides, need I say more ($1,200) (review in this issue). The all digital front end, rests on the top of the line Target Stands, where each component rests Osiris Ariel pnuematic component stands. Amplifiers, in addition to the VR6's rest on the awesome Osiris Giza Bases. Digital cables were provided by NBS, out of transport, into Z-sys, and Illuminati Balanced, out of Z-sys, into DAC. (Watch out for the astounding Harmonic Technologies cables, this new company, saw time in the system, and look out for the review of possibly the best cables ever to grace the system ever!) Black Diamond Racing Products adorn the entire setup, wherever there are feet, be sure they're coming to rest on "Those Things."

After finding out what my system cost I guess Chris had my number, so they decided to send me their upgraded Audiophile Reference Passive unit which retails for $395.00. How the unit came about is quite interesting and provides some background on how the device works. Arturo Garcia and his son, Art, co-inventors of the TDS Technology, are versed in multiple science disciplines. Their ability to develop the TDS technology, a combination of electrical and sound engineering as well as acoustic and psycho-acoustic theory, is the result of superior intellect coupled with an inventors curiosity and drive to discover. The genesis of the TDS Harmonic Enhancement Technology is the result of Arturo Sr.'s work and belief that the harmonic signature of a sound wave could be significantly restored. After years relentlessly developing this theory, he had achieved his goal of developing a technology that could restore the harmonic spectrum of sound so completely, that all audio signals would be perceived with unparalleled presence, detail and clarity. Together with his son, the two inventors then spent the next several years developing an electronic audio version of his original theory, now known as the TDS Harmonic Enhancement Technology. Until recently, TDS was used primarily in professional recording applications. TDS has been used to enhance the sound tracks of several feature films including "Jerry Maguire".

The TDS website ( states "after auditioning thousands of dollars worth of sound enhancing equipment, the sound engineers and mixers concluded that TDS gave them superior sound quality." I perused the White Paper looking for more technical info to sink my teeth into. After all, even Alfred E. Numan has got to explain himself! The Paper states "The TDS is a hard wired passive inductive circuit that takes the shape of a transformer coupling and employs no resistors, capacitors or active elements of any kind, making it the purist mode of reproducing sound. Employed interstage, it exhibits a high DCR and impedance at the input and output in order for it to operate with minute current. Unlike conventional sound enhancement technology, the TDS technology does not employ phase change or time delays as part of its effect. It simply enhances the harmonics that already exist within the original signal, BUT ARE INAUDIBLE WITHOUT THE TDS ENHANCEMENT." The paper goes further to discuss how it works: "Basically, the TDS works by introducing a non-linear amplitude distortion of select frequencies within the audio band and beyond, thereby imparting an increased sound stage, along with greater separation, low-level and/or ambient information and detail that would be much less apparent without the TDS enhancement." This was about all I could read before I flew into my listening room, prepared for some serious evaluations! Now where are those old 3-D glasses when I need 'em? While I was hooking up the infernal machine, I couldn't help but remember the ad's promise: "The intent of TDS enhancement Technology is to enable the audio signal to sound more natural and live, like the original performance." "Right," I bellowed, putting on my glasses.

First disc up was the new Clarity Records CDD-1012, Jeremy Cohen's "A Taste Of Violin Jazz." Duke Ellington's "In A Sentimental Mood" proved to be an exceptional recording without TDS; with it, however, the music took on an entirely different perspective. First, Paul Mehling's guitar strumming seemed to be coming from farther away, greatly stretching the depth perspective. Jeremy's violin, however, was projected forward, with the stage taking on gigantic proportions. There were musical nuances layered in three dimensional space that I didn't hear before. In addition, Jeremy's violin took on a special quality that sounded more analog, more rounded and less opaque. The opaque issue comes from a "flattening" that I believe is inherent in the digital recording process, resulting in instrument outlines being synthetic and homogenized, without that rounded fullness so well done by analog. Indeed, the TDS device greatly eliminated this digital artifact, making each instrument sound much more full bodied and warm. However, this roundness did not come at a penalty of syrupy, slow transients that often accompany so-called "musical" components. Another, quite unbelievable asset of the TDS, is it's ability to open up your listening room, if you have a small space such as I (16 × 13 × 8). You will be amazed by the way this small devices provides huge improvements to the overall sound stage. It literally dissolved my front wall, replacing it with live musicians instead.

I believe that the KR Enterprises VT800 amplifiers have a lot to do with the systems timing and pace, as well as the high speed VR-6 speakers, yet I am also convinced that the TDS unit has no detrimental effects regarding either clarity or speed of transients.

Jeremy's violin had the right amount of "bite" on the strings, I could even hear the rosin on the bow. Along with this increased detail came spooky holographic imaging, I could clearly "see" where Jeremy was standing while playing the violin. I suddenly realized that I didn't need my 3-D specs any longer!

Talk about multi-tasking. Play the 1987 CD of Ariel Ramirez - "Misa Criolla" featuring a young Jose Carreras. The TDS device placed the chorus in their own natural space, while simultaneously allowing me to hear the exact phrasing of the mallet tapping the tympani ever so softly, while Jose's voice floated in space so dimensionally. I literally got goosebumps! This recording used period instruments, and for the first time, I understood why. The tonality of each instrument seemed highlighted, with none of the homogenization indicative of the digital recording process.

The TDS device also has this uncanny ability to "clean" up the upper midrange and treble on many recordings with less than stellar quality (read: commercial CD's). I believe the most fascinating thing about the TDS processing was that I could take off my reviewer's hat and just enjoy good 'ole music, warts and all. I can't begin to tell you how much simpler this has made my life. After putting together such a revealing system, I was worried that I was not going to be able to enjoy the bulk of my music collection. I've heard of poor souls lost in audio hell who could only play three recordings for their friends! I say, bring on the TDS and let them eat cake!

All that being said, what about comparisons to another competing enhancer, the HRS? They certainly have a lot in common with regard to size, price, and both go between either cd player and preamp. (Unless, like me, you use the volume off your dac) But that's where the comparisons end. The TDS sounds very different, probably because it's passive. It excels in the signal purity category, clearly reducing background haze. The HRS, although an active unit, is designed to be very simple, so much in fact, that switching to an inferior power cord is audible. (HRS does provide the excellent Custom House power cords, however, mitigating this concern.) Simply put, the HRS enhances the signal from bottom to top, while the TDS enhances the sound from front to back. They are both difficult to accept on a purist level since they are devices inserted into the signal path. However, in my system, they both performed very well, making their use more of a blessing than a curse. The TDS unit expanded the space between the instruments, providing a birdseye view into the heart of the performance that otherwise sounded congested. While the HRS simply magnifies the entire signal, it also tonally enhances each note with more palpability, making each note "pop" out of the sound field. The ability of the HRS to let you hear down into the noise floor is quite uncanny, creating a black and velvety background. The TDS doesn't do this trick, it does it's magic,by adding more space time, and dimension to recordings.. Shall I share the utter decadence of using both cascaded? "Scotty, set phasers to stun!".

When I connected both simultaneously, using the TDS after the HRS (hooking up the TDS into the HRS caused problems), I couldn't believe my ears. First of all, the sound of each remained the same, with each unit's attributes remaining apparent.

The units didn't fight each other or seem to cause any type of unwanted distortion.

The first disc up was "Keith Jarrett At The Blue Note, The Complete Recording." CD 4, track 5 entitled "The Fire Within" is absolutely gorgeous sounding, as are most ECM recordings. With the HRS/TDS now in the system, the music took on very dramatic aspects. The treble range became even smoother and creamier than I have ever heard. The tiniest portion of digital glaze and "edge" left in the system was now banished . There was an added sense of relaxation -- like analog! Tonally the sound was richer and possessed more body. The "life" of the music stood out vividly, while also sounding more intimate, excelling in both timbre and tonality. Jack DeJohnette's cymbals took on a texture that was more convincingly real, especially in it's decay as if someone sprinkled cymbal dust into the air like a fine smelling aerosol spray. Keith Jarrett's piano solos were well sculptured through each note, the HRS/TDS combo. Transients lost more of that edge, still avoiding that rolled off signature, sounding rounder and again and again, more analog.


At first, I noticed a very slight lack of transparency, like a cloud hovering over the overall sonic picture. To determine whether this was due to a new interconnect I had to use, I removed the TDS, listened for a few days, then removed the HRS. After listening for a few more days, only to the TDS, here are my conclusions.

The TDS is an extraordinary piece of equipment, not lacking in transparency or detail. It's passive, of course, and priced dirt cheap for what it offers (fun per dollar, naturally). Its performance in my system was stellar and I chose to keep it permanently. One of the nicest features it provides, is the ability to clean, like detergent, your systems overall sonic texture. For me, that alone is much to praise in something this affordable. But, like when purchasing a new car, if it's fully loaded, power windows are merely one of it's amenities. That says volumes about its capabilities. I had Chris send one to a friend, Bill Brassington ( lovingly referred to in Stereophile as the Brass Ear). Bill called me a few days later, wanting to know if I had ever tried wearing 3-D glasses while listening to my stereo! He also chose to keep the unit in his incredible system. Ezra, another friend from Chicago and a devout Christian and practicing minister, also tried the HRS in conjunction with the TDS. Naturally, being a minister, he married the two units in holy matrimony! Guess who served as "best man"... "Nuff said.

The TDS system is certainly of reference caliber and a great surprise to those who question everything considered a black box. It's absolute heaven, and a must if you have large collections of less than great recordings. Highly recommended!

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