Recommended Components

Audio Research Tube Damping Rings: $5 each ★
Damping rings for all AR products are now available to the public at large. They're made of a proprietary polymer material that converts kinetic energy to heat, and their improvements are not subtle, exclaims BJR: tighter, cleaner, deeper, more dynamic bass; more coherent transient attacks; crisper, more extended highs; plus "improvements in the reproduction of subtle gradations of low-level dynamics." Give 'em a whirl—the cost is minimal. (Vol.23 No.2, Vol.26 No.8)

AudioQuest binding-post wrench: $17.95 ★
A great idea improved—similar to the original Postman, but with a metal sleeve reinforcing the sockets. (Vol.20 No.9)

AudioQuest JitterBug: $69.95 $$$ ★
With its USB Type A jack at one end and USB Type A plug at the other, the AudioQuest JitterBug is scarcely larger than the memory stick it resembles, yet its internal multilayer circuit board is packed with tiny surface-mount resistors, capacitors, and what appeared to JA to be common-mode chokes. The purely passive JitterBug, which is claimed by AudioQuest to remove noise currents and parasitic resonances from both the data and power conductors in USB ports, is intended to go between the computer and the USB DAC of a computer-music system; a second JitterBug, plugged into an unused USB socket on the computer, is said by the manufacturer to confer additional benefits. After using the JitterBug with his Mac mini, JA wrote, "I wasn't expecting the degree of improvement the JitterBug wrought with the first recording I played." He reported that low frequencies gained authority, applause sounded more like hands clapping than generic noise, and that once-clangorous pianos sounded, in the same challenging passages, more natural and smooth. From his test bench JA wrote, resignedly, that his measurements "didn't reveal why using the JitterBug improved the sound—which it most certainly did." ML started down this road by plugging JitterBugs into four USB sockets in his computer- audio rig. Upon removing all four, he heard a subtle loss of clarity. Reintroducing the 'Bugs one at a time, ML noted the most dramatic improvement with one, and a lesser but still appreciable refinement with a second—but after that, the "very subtle sonic gains" weren't worth the extra money: "One JitterBug = good. Two JitterBugs = better." Just when we thought there was nothing more to say about the AudioQuest JitterBug, KR tried it and wrote that he could hear its positive effect on a USB DAC's analog output: "When I removed the JitterBug, I missed it." (Vol.38 Nos.9 & 11, Vol.39 No.1 WWW)

Ayre Acoustics Irrational But Efficacious System Enhancement CD: $20 ★
Ayre's test CD includes five tracks of various white, pink, and brown noise, as well as two glide tones that sweep from 5Hz to 20kHz. The disc produced a less electronic sound in JM's system, while lowering the noise floor and improving microdynamics. "I am flabbergasted," said he. "Highly recommended."AD adds that this CD should be used "with caution, and with the understanding that, as with trying to measure a transformer with a DVM and unintentionally magnetizing the core, negative results may ensue and may take a few days to fade away." ST points out that "weird shit goes on in hi-fi. Don't dismiss it until you try it. I use this thing, too. Just don't play too loud." (Vol.33 No.12, Vol.34 No.2, Vol.36 No.10 WWW)

CAIG DeoxIT GOLD Wipes K-G1W-25: $24.95/25ct; K-G1W-50: $44.95/50ct ★
These small pads are made of a slightly abrasive textile that has been impregnated with Caig's DeoxIT Gold contact cleaner. JM uses them on the outside of RCA jacks and on the pins of RCA plugs to treat corrosion, oxidation, condensation, and general grime. JM: "A small but powerful stocking- stuffer...You'll feel like a pro!" (Vol.25 No.12, Vol.36 No.10 WWW)

ETI Copper LINK (Bullet) Plugs: $129 (pack of 4)
ETI Silver LINK: $279 (pack of 4) ★
Originally called the Eichmann Bullet, this RCA connector uses a clever design in which the hot signal is conducted by a hollow rather than a solid pin, and where a smaller, solid pin at the connector's periphery takes the place of an unnecessarily massive ground sleeve. AD heard "a more open and explicit sound" with a "deeper, more open, and more inviting" soundfield. Silver Bullet Plugs made the difference "clearer, more explicit, and even smoother." (Vol.27 No.12 WWW)

iFi iPower (5V, 9V, 12V, 15V): $49 ★
The iPower is an ostensibly perfectionist-quality wall wart, said by manufacturer iFi to produce very little noise. The buyer selects the iPower whose output most closely matches the playback gear in question, the choices being 5, 9, 12, and 15V; beyond that, this wart is virtually universal: the AC end accepts any of four AC plugs (supplied), so that the iPower can be used almost anywhere 100–240VAC is available. Its DC cable is terminated in a 5.5 by 2.1mm DC connector—but again, iFi supplies adapters for an addition three sizes (3.5 by 1.35mm, 4.0 by 1.7mm, and 5.5 by 2.5mm), along with a polarity inverter for devices requiring a center-negative supply. Can a better wart make for better sound? According to KR, "recordings with open, ambient soundstages sounded cleaner, and both instrumental and vocal music was more distinct. This was no major change that struck me every time I listened, but it did make all of my listening much more relaxing." (Vol.39 No.3 WWW)

Intona USB 3.0 Galvanic Isolator: $369 (plus cable)
This small module fits between a source component’s USB Type A port and a D/A processor’s USB Type B port. When HR first used it with the HoloAudio May processor, he “jumped back,” he wrote. “The sound changed more than I expected it would.” When he removed the Intona, “the soundstage was drier, flatter, and smaller. Instruments sounded plain. Reverberation on the recording was noticeably reduced. Music was less intoxicating.” JA found no measurable differences in the output resulting from inserting the Intona between a MacBook Pro and various D/A processors. (Vol.43 No.8 WWW)

Littlite L-18-LED: $99.95 ★
The latest generation of Littlite mixing-console lamps provides high- efficiency, long-life LED illumination; a rotary switch selects clear white or red light. JM finds the 18" version especially helpful near a turntable or CD player. (Vol.36 No.10 WWW)

Magnum Dynalab 205 Signal Sleuth FM Booster: $499
We've left this on the list forever, because there's not much for FM fans these days, and because this unusual, niche product has shown amazing staying power. This is not your typical powered antenna amplifier. It's a notch filter that preceeds the tuner with 18dB/octave edges, so it amplifies only the signal you want—sort of a pre-tuner tuner with selective gain. You can use it to attenuate signals that are too strong, and if you want to hear stations that are easy to receive, there's a pass-through. Best with old-fashioned analog radio signals. (Vol.10 No.6)

SOtM tX-USBhubIn: $350 ★
This horribly named accessory, which requires power from the SATA interface of the computer or computer-based server into which it is plugged (a SATA Y- connector may be required), is a USB repeater intended to preserve the integrity of the signal reaching an associated USB DAC. In KR's estimation, the tX-USBhubIn "made an easily audible improvement in the sound of a system that I'd already thought sounded entirely satisfying." (Vol.39 No.1 WWW)

UpTone Audio USB Regen: $175 ★
UpTone Audio's USB Regen is a wall-wartpowered accessory designed to regenerate both a USB datastream and the USB bus's 5VDC before either makes its way to the DAC in a computer-audio setup. Intended to be installed between the user's computer and DAC—UpTone advises siting the Regen as close as possible to the latter, and includes a solid male-to-male adapter to enable this—the Regen is built into a sturdy aluminum case just slightly larger than a Fig Newton. (The Regen's wall wart is about three times the size of the Regen itself, and is of higher-than-average quality.) As for the Regen's audible effect on a computer-audio system, ML said, "Wow: not subtle," and described the Regen as the most effective such accessory he'd tried. Commenting on the effects of the UpTone Regen on one of his multichannel systems, KR wrote, "all hints of the abiding brightness were eliminated and, as a result, the frequency balance was smooth and unaccented." In a Follow-Up, and JA found that the Regen made no measureable difference in the output signal of an associated USB DAC. He also discovered that installing the Regen without first deselecting the associated DAC as an output device and twice relaunching the file-playing software—once before adding the Regen, and again after installing it and reselecting the DAC—served to prevent his system from playing high-resolution files at anything higher than 16-bit/44.1kHz. Whee! (Vol.38 No.11 WWW)