aM.jpg (10462 bytes)

hardware.jpg (10798 bytes)



Symphony Pro

as reviewed by Francisco Duran and Dave Clark





ProAc Response 2s.

Reference Line Preeminence IA passive. Monarchy SM70 amplifier.

EAD DSP 1000 III DAC. Pioneer DP 54 as a transport.

Kimber Hero interconnects, Acrotec 1050 speaker cables, and LAT digital cable.

Panamax PLC.


one.jpg (6551 bytes)   Being an audio buff for many years has taught me at least one thing: If a product doesn’t work perfectly in one system, it often does wonders in another, especially when it comes to tweaks. I’ve had success, to a greater or lesser degree, with cones, pucks, boards, sound reinforcement panels, air bladder platforms, speaker wire lift devices, and other tweaks over the years, but let me tell you, success doesn’t come easy. You have to work at it. So, when a product like the Quantum Symphony Pro comes along—a device that you simply plug into a wall outlet next to the outlet in your stereo system and flip a switch—I think that’s great. The Symphony Pro is not just a tweak. A brief explanation is that it works on a sub-atomic level to "align" the electrons in your AC lines, making electricity more conductive and more efficient. (For a better introduction to this technology, see the comments of Bill Stierhout of Quantum in the June issue of Stereophile.)

Substituting a Monarchy power cord for the stock cord that came with the Quantum Pro, I first plugged this unit into the same receptacle that I have my Brickwall Filter plugged into, then turned it on and forget about it for a couple of weeks. Later, I moved it around to other outlets nearby. (Yes, I tried the stock power cord, but heard no difference.) Finally, I took the Quantum Pro out of the picture completely. Not only did I shut the unit off, I unplugged it and moved it away from the receptacles—I didn’t want any electrons fooling around where they weren’t supposed to. It was only when I removed the Quantum Pro that I noticed what it was doing. I kept thinking to myself, "What happened to the sound?" A slight but very noticeable cleanness had been lost. Music was less liquid and less round. The best word that I can think of to describe it is that the music did not sound as "slick" without the Quantum. The effects didn’t knock me over the head when I first plugged this unit in. They are subtle, but not any less so than other line-conditioning devices I have tried in my system. I sure noticed the effects when I took the unit out, though. After it was gone, it was something I really wanted back.

Quantum states that the effects of their devices are cumulative. Right now, I am in the middle of a wire change for my system or I would buy a couple of the Pro units. I liked it that much. Give me time, though. Quantum also makes a less expensive version, the Symphony at $299 and the Octave, an eight-receptacle in-line power conditioner that sells for $500, so you do have choices. There is also a money back guarantee for the weak at heart. So don’t be chicken, try it out.
Francisco Duran





Reimer Wind Rivers.

Clayton Audio M70 monoblock amplifiers. HRS unit and Taddeo Digital Antidote Two. E.A.R. 834P phono stage.
Blue Circle BC3 preamp w/Amperex BB tubes, and BCG3.1 power supply.

EAD T1000 transport and 1000 Series II DAC with Audient Technologies’ Tactic and Audi, Nordost Moonglo digital cable. Linn Axiss turntable with K9 cartridge and Basik Plus arm.

Nordost Blue Heaven and SPM interconnects, and SPM bi-wired speaker cables.

API 116 Power Wedge and Coherent Systems Electraclear EAU-1 parrallel conditioner. Dedicated 20 amp ac circuit. BDR cones and board, DH cones, Vibrapods, various hard woods, etc.


two.jpg (6646 bytes)The Quantum Symphony is a parallel AC device that is quite reminiscent of the ElectraClear EAU-1 reviewed back in Issue 2. The two devices work on similar design principles. Both are plugged into the wall and nothing is plugged into them, and both are said to "align" the electrons in your AC, resulting in a more conductive, smoother, and less noisy flow of current in your system. The language used by the two companies differs, however—ElectraClear uses the term "coherent technology," whereas Quantum refers to "quantum resonance technology" or QRT. What does all this mean? Well, for the EAU-1, read Issue 2 or click here. But I will say that I liked it enough to buy it, used it with great enjoyment in our main system, and with the arrival of the Quantum device, still use the EAU-1, though now in our video system, where, by the way, it works just as well. As for the Quantum Symphony, well okay, the rabbit is out of the hat. I liked the Symphony enough to buy it, too. No, I am not rich, but when something as good as the Symphony comes along, it is hard to send it back!

With the Symphony in place, music takes on a more relaxed presentation, with a smoother flow, and less noise riding along in the background. Images appear more stable, rounder, and richer. There is greater dimensional palpability. That is, the soundstage goes deeper, with more 3D presence. And all from, or really within, a "blacker" blackground. That’s as cliched as one can get, but so what? It works. I simply hear more "natural" music, with less noise and grain. The effect is roughly twice that of the EAU-1.

While, as I said, the music—or more specifically, the images within the soundstage—is smoother, rounder, and more "relaxed," this does not mean that it becomes duller, less defined, or pace-impaired. The music actually gains in dimensional texture, becoming more lifelike. Guitar strings take on the resonance and texture that makes real strings sound real and recorded strings sound recorded. Any hint of electrical "masking" is removed. Also, glare is removed and replaced by a more natural presentation reflective of live music. I can listen much longer, with less strain and fatigue. I hear less distortion, which may be a byproduct of there being less noise. With the Symphony, there is an enjoyable ebb and swell to the music that, sans Symphony, is somewhat obscured. as for pace and rythym, I find myself doing more dancing with the unit in the system than I did before. None of this is really dramatic, but enough to make the pedestrian a front runner.

I really like what the Symphony does to our system. No, make that I really like what it does to our music. It may not do the same for you, as AC can be a tricky devil to deal with. It all depends on your service grid and surrounding environment. As a side note, we have two dedicated lines running AC to our system, one being 20 amp for the amplifiers and the other being 15 amp for sources. I also use a home-brewed AC conditioner based on industrial Corcom filters, ferrite blocks, Harmonic Technology wire, and Cable Jackets. It’s really tweaked, and works better than an API 116 PowerWedge. The Symphony is used on the 15 amp line.
Dave Clark

Quantum Symphony Pro
Retail $599

Quantum Products