Perhaps you remember them. Four or five years ago, the Bybee "filters" for use with interconnects, speaker cables and power cords were some of the hottest aftermarket accessories around. Curious about how those mysterious devices worked, I acquired multiple samples, and after a few months wrote a glowing review of them in the final issue of FI magazine. But about a year later, those terrific products went out of production. Not for lack of sales, but because their inventor, theoretical physicist Jack Bybee, got tired of slaving all day at his work bench, chasing slow-paying retailers, and dealing with a partner with whom he had irreconcilable differences. These days, those older Bybee products occasionally turn up on eBay, Audiogon and other sites, where eager audiophiles snap them up quickly for high prices.
Since he stopped making those various outboard accessories, Jack Bybee has been offering their key functional elements -- which he calls Quantum Purifiers -- for use in internal modifications to loudspeakers and audio/video components, marketing them primarily through upgrade specialists. A few high-end manufacturers have also begun incorporating Quantum Purifiers into their products. Albert Von Schweikert, for example, uses them on the tweeter and midrange driver of his dB-100 loudspeakers, which I reviewed in the January Review Magazine. He readily admits that these little devices are a critical factor in the impressive sound of those speakers. Quantum Purifiers are now resident in all of my reference electronics and my Eggleston Andra loudspeakers -- and it's unsettling to even think about going back to the dark days of pre-Bybee listening.
Quantum Purifiers in the raw state are cylinders with copper leads at both ends. They come in two sizes: the large ones are roughly 3/4 inches in diameter and two inches long. The small ones are 1/2 inch x 1 inch long. The large Quantum Purifiers are typically used in treating AC, high-current circuits and loudspeakers. The small units are functionally identical, but carry less current because their leads are thinner. These small devices are the ones used in the new interconnect purifiers.
Each Quantum Purifier comprises damping and shielding materials surrounding a special ceramic, which in turn surrounds a resistor. The ceramic is made of numerous rare-earth metal oxides; the formula is still classified by the U.S. military. Jack Bybee was a leader of the group which originally developed this technology, which was originally applied to quieting the power systems in nuclear submarines to enable the best possible sensitivity from the subs' passive sonar systems. Other applications are still classified, and Jack does not publish any specifications. The absence of such data is now and again deplored on the Internet, and charges of fraud and "snake oil" occasionally appear. Jack is quite at peace with the reality that the "you can't hear it if I can't measure it" and "if it's not in my college physics book, it's not true" types who haunt the Internet forums will most likely reject the Quantum Purifiers without trying them, and possibly even after trying them. The closed mind is mightier than the ear, I suppose. In this writer's opinion, anyone who can't hear the musical benefits of this technology is barking up the wrong hobby.
Recently, Jack began tinkering with a new kind of plug-in interconnect accessory, thinking he might build a few pairs for himself and friends -- among whom I am pleased to count myself. He came by a few times with samples for me to try, and every time, the latest version was better than the previous one. Finally, he had something so good that everybody who heard it agreed that it was a shame that more music lovers wouldn't be able to benefit from them. After some consideration, Jack decided to begin building his new devices in limited numbers for retail customers. Ergo, this article. (I understand that our esteemed Senior Editor Dick Olsher has agreed to evaluate the raw Quantum Purifiers in various applications, beginning in July. So, be on the lookout down the road for Dick's report.)
Purifier? Filter? Whachamacallit?
The keen-eyed reader will have noticed the quotation marks around the word "filter" above. That's what people started calling Jack's original products, and the name stuck. But Jack's own term, Quantum Purifier, not only sounds snappier, but is really more accurate. Yes, the QP does perform a filtering function in removing noise, but it operates on the quantum level. Quantum noise is difficult if not impossible to measure with typical bench instruments -- and the QP is not designed to filter out gross noise such as RFI and EMI. (One high-end maven crowed to me that he had measured some Bybee devices, and they had no effect on RFI levels -- so they were clearly bogus. Oh well.)
The QP does not behave like a filter in other respects. Virtually every kind of filter comes with some kind of trade-off or negative trait that offsets its benefits. Common examples are frequency response aberrations and phase shift. The totally passive QP has no effect on frequency response, and introduces no phase shift whatever. It is also non-reactive -- i.e., it eliminates the sonic effect of the interaction of inductance and capacitance. As a result, the QP is a benign presence in any kind of circuit or signal path. Quantum Purifier is really the right name.
The differences between the old and new interconnect purifiers begin with the form factor. The original device had the QP element potted in a cylinder measuring roughly 1 inch x 3 inches, with an RCA Jack on one end of the cylinder and a three-inch length of interconnect at the other end, terminated with a locking RCA plug. The thought was to take pressure off the device by letting it hang down, more easily accommodating the weight of the interconnect. The new design is an irregular cylinder about 3 inches long, with the RCA jack at one end and the RCA plug at the other, with no length of interconnect. This is a much simpler and more direct connection, which I think is one factor in the improved performance. Jack does build strain relief into this structure, but the user would be well advised to support the purifier, as the weight of many interconnects will otherwise be problematical.
The other major improvement in the new interconnect purifier is the use of cryogenics. Jack now cryo-treats every QP element, and he also cryo-treats the other parts (jacks, plugs). Then, the finished interconnect purifiers are cryo-treated again, which assures that the solder joints also take on the characteristics of post-cryo conductors. In my experience, the cryo effect is a more relaxed and liquid musical presentation, with significantly better low-level detail retrieval (especially ambience cues), and improved dynamics. And that, my friends, is also a pretty good summation of what the Bybee products do.
The Single-Blind Challenge
In addition to the numerous Quantum Purifiers internally installed throughout my system, I also have a number of the original interconnect "filters" and some earlier versions of the new offering. I have continued to use the external plug-ins to augment the effects of the internal mods, because several years of working with this stuff has taught me that their effects are incremental -- i.e., the more you use, the better the sound gets (and picture as well -- one device on the end of my coaxial video interconnect immediately improves the brightness, color fidelity and edge definition of a DVD picture).
The process: I enlisted the help of a willing friend, who substituted, in random order, the original, intermediate and latest versions of the interconnect purifiers. They were placed at the end of my Graham phono cables at the phono stage inputs, between CD player and preamp, and between preamp and amplifiers. Because they were handy, we tried both the new Aria hybrid amps (tube input stage, solid-state output) and my trusty VTL MB-750 reference amplifiers. Recordings included the great-sounding Reference Recordings CD of Leonard Bernstein's music, to judge dynamics, tonal sweetness and spatiality; Renee Fleming singing Richard Strauss's Four Last Songs, as good a vocal test as you'll find; and Emmylou Harris's Wrecking Ball, to see how well the incredibly dense mix could be deciphered. LPs included the 45-RPM Classic Records reissue of Dorati's Firebird, Nojima Plays Liszt, and my age-old copy of the Rolling Stones' Sticky Fingers (a long story... but it works for me).
The play-by-play would be boring. The bottom line, as we hard-nosed analytical types like to say, was that my recognition was near-perfect for about the first 45 minutes. After that, I occasionally missed the difference between the intermediate and newest purifiers, though never between the original and newest. I have serious reservations about the efficacy of quick-switch testing, but for some reason -- perhaps the 90 seconds or so between each listening, as the purifiers were switched -- these tests didn't bother me. I was already certain of the progressive improvements heard in these three generations from listening to all of them at my leisure. This test was really just a confirmation.
As you might infer from the above, these things work great on any single-ended interconnect, analog, digital, video. The optimum placement is always at the receiving end of the interconnect, closest to the final destination of the signal. I almost hate to tell you this, but putting the purifiers at both ends of the interconnect provides another significant improvement.
The original interconnect purifiers sold for $600 retail. The new improved ones list for $750, although as I write this (June 2002) there is an introductory price of $600. That's a lot of money, I know, especially for an "accessory." But I don't regard these things as just accessories. The improvement in musicality that they provide is little short of miraculous, in my opinion.
"But," I can hear you saying, "$600 -- or $1,200 -- to treat one pair of interconnects?" I hear ya. But here's the thing: I know lots of audiophiles who regularly pony up two or three large for "state-of-the-art" interconnects. And some of that wire is truly outstanding. Some, though not so much, to my ears in my system. So, for perspective, let me described to you another kind of testing I have done over time with the Bybee stuff. I got the idea a few years ago, when the Stereophile show was in Los Angeles. Jack Bybee was there, and I tagged along while he went into various rooms and persuaded the proprietors to stick his cables into their systems in place of the megabuck wires they were using. To near universal astonishment, Jack's wire was in usually decidedly better; sometimes it was a close call. What was Jack's miracle interconnects? They were some thirty-buck Mogami wire with a Quantum Purifier at each end, just before the RCA plug.
Since that eye- and ear-opening experience, I have repeated this experiment with many different brands of audiophile cables. My results have been that lower-priced interconnects with the interconnect purifiers almost invariably sound better than higher-priced wire that costs more than the competing combination. Also, I have yet to encounter any interconnect that is not improved by the Bybee purifiers. I guess I won't make any new friends among cable vendors with this declaration, but that's the way I hear it.
The very best sonic improvements from Bybee products are obtained by internal modifications. I believe most of the specialists who do mods with Jack's Quantum Purifiers charge @ $85 each plus labor. So, let's say you decide to do your amplifier (or CD player, etc.) and you agree to have six purifiers installed in it. You are probably looking at roughly the same investment as buying a pair of these interconnect purifiers, and for that money you're going to get a bigger sonic bang. On the other hand, the external purifiers are infinitely portable -- you can even stick them in your pocket and take them over to blow away your friends. One way or another, I think you owe it to yourself to hear what these remarkable devices can do for you.