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Positive Feedback ISSUE 13
may/june 2004



RT800 AC Source/Conditioner

as reviewed by Tom Campbell






Harbeth Compact 7-ES; Spendor SP 3/1P (secondary).

Coda/Continuum Unison integrated amplifier; Marsh Sound Design A-200S solid state power amplifier; Marsh Sound Design P-2000T tube preamplifier; EAR 834P tube phone preamplifier.

VPI HW-19 Mk III turntable with Audioquest PT6 tonearm; Grado Reference Sonata cartridge; Sony DVP-NS999ES SACD/CD player; vintage Luxman AM/FM tuner.

Signal Cable interconnects, speaker cables and power cords; River Cable FLEXYGY speaker cables; Siltech ST-48 interconnects.

Vibrapods spread liberally through system; QS&D 4-shelf component rack; Sonex acoustic panels in listening room.


Audiophile power conditioning has become an increasingly crowded field in recent years. In doing a little internet research for this review, I was surprised to discover the extent of the competition. Some products, like the popular PS Audio Power Plants, are huge contraptions with massive transformers, essentially amplifiers to run your amplifier. Others, like the extensive line of home theater products from Monster Cable, are filter devices that "clean" the dirty AC power coming out of your wall. Though competing in the same field, the Quantum RT800 is neither a transformer nor a filter device.

According to Quantum, the RT800 is concerned with electromagnetic fields: "The RT800 conditions the space occupied by (electromagnetic) fields of any kind…. (It) employs a unique and cutting edge technology, Quantum Resonance technology, based on research into the random behavior of photons and electrons in AC electricity…. The goal is to affect a more ordered electron behavior…." The product literature goes on at length, in sometimes-dubious verbiage ("Principles of musical composition and other proprietary methods are used to generate an extensive array of field patterns."). As is the case with virtually all AC devices, Quantum’s claims for the RT800 are not provable by objective measurement. Like its competitors, Quantum offers information about improved signal-to-noise and more ordered electrons, but this remains very fuzzy science. One can only go by what one hears. 

I immediately liked the RT800's unostentatious style. It is a simple, solid, smaller-than-a-shoebox design, with an aluminum faceplate and eight well-spaced outlets. It's easy to place behind an equipment rack and out of sight. While the RT800 may not impress "My monoblock is bigger than yours" types, most will find it nicely understated and space-efficient, though at $1350, it would be nice if its lack of pretension in appearance was matched by a lack of pretension in price—this little box costs more than half as much as my Harbeth Compact 7 loudspeakers! In fairness, however, the RT800 is competitively priced with conditioners from PS Audio, Richard Gray’s Power Company, and others.

The RT800 is designed as a full-system solution, so I auditioned it as such. It replaced the humble Monster Cable HTS-2000 power strip (circa $200) that I bought a few years ago. I have always been satisfied with the HTS-2000’s performance (improved clarity and dynamics, deeper bass). I've never regarded it as a weakness in my system, so I've never replaced it, despite upgrading most of my other components. Given its price, the RT800 is clearly intended to play in a different league, so I was very curious to hear the kind of difference it would make. I let it sit in the system for a week or so before starting to draw conclusions. It sounded quite closed in for the first few days. Once I began listening in earnest, the first CD to provoke a "wow" response was, surprisingly, Bob Dylan's 1992 Good As I Been To You, a terrific solo run-through of classic British and American folk tunes. The early-‘90s mastering is a bit hard, but the hardness was completely eliminated by the RT800. In fact, everything sounded great. Ol’ Zimmy was in the house, with an improved sense of depth and bloom and dimensionality.

The wows continued when I slipped in Los Lobos' Kiko, another great ‘90s record that had sounded somewhat thin and bright but now sounded wonderfully warm and three-dimensional. It crossed my mind that the Quantum might be honey-coating things, but it didn't seem that way—dynamics were retained and the top end didn't sound chopped off. My honeymoon with the RT800 lasted several days, as almost everything I fed it sounded big, lush, wide, and deep, with no hint of digititis. I wondered whether "digital glare," an almost universally recognized as a downfall of CD sound, was largely a matter of AC interaction. Was the RT800’s "electromagnetic stabilization" the silver bullet after all this time?

Unfortunately, the answer was no. At first, I was so busy dusting off older CDs that I listened to comparatively few newer and better-mastered ones. When I did, I came to the conclusion that, while the Quantum did a miraculous job of removing the edge from sharp-sounding discs, it had a softening and slightly dulling effect on ones that didn’t need the help. The depth and bloom that had enhanced lesser CDs sounded excessive and sometimes artificial on audiophile-quality discs. I played my copy of Sonatas for Cello and Piano (Wispelwey and Lazic playing Shostakovich, Prokofiev, and Britten on Channel Classics), a wonderful SACD with a pristine top end. The sound was thicker than usual, and the highs weren't there. What was left sounded pretty, to be sure, but there was some definite sweetening going on.

Since a sparkling top end is one of the primary advantages of SACD, I continued this area of investigation. Blueswoman Rory Block's Last Fair Deal is a fine-sounding disc, but was recorded in a reverberant acoustic that is just this side of being too much. With the RT800, the reverberance was magnified and the images artificially big. I wanted to be fair, and reasoned that perhaps the Quantum was exposing hi-fi gone awry, but the trend persisted, and my opinion became firm that the RT800 was not only slightly blunting the top end but adding a recessed quality. I became increasingly aware that certain details were being pushed farther back in the mix. This created the impression of a very wide and very deep soundstage, but in my system, this was just too much. I tried switching cables and amplification, but found that the Quantum’s character was consistent. 

It should be noted that the "BBC dip," a midrange bump that enhances depth and imaging, is engineered into many brands of British audiophile equipment, and both of my loudspeakers of choice, the Harbeths and the Spendors, are famous for incorporating it. (The effect is more pronounced in the more overtly ingratiating Spendors.) It could be that my speakers and the Quantum were an unhappy match, and produced too much of a generally good thing. From conversations with audio dealers, and e-conversations with PFO readers, I know that brightness is the #1 complaint that people have about their systems. For those seeking to tame a hard tonal balance, the RT800 could be a godsend. The more dogmatic among you might say that that this is treating coloration with coloration, to which I say that every system is about balancing biases—in equipment, in rooms, and in the AC interface.  

The Quantum RT800 didn’t work for me, but the performance of AC devices, like that of cables, is notoriously system dependent. Your mileage may vary, so don’t be afraid to audition the Quantum. It’s a nicely thought out design that offers several practical advantages. Whereas some competitive products have only one or two outlets, or are designed specifically for amplifiers or front-end components, the RT800 is an elegant one-box solution. Tom Campbell

Quantum RT800 AC Source/EMF Conditioner
$1349.95 (15 amp version)
$1449.95 (20 amp version)

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