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Equipment Review

December 1998

Audio Power Industries Ultra Power Wedge 116 and Ultra Enhancer 2

by Greg Weaver

Garbage in...

API Ultra Power Wedge 116


Review at a Glance
Sound Easy-to-discern improvements in clarity, bass speed and depth, and dynamics. Noise floor dropped noticeably -- silence "sounded like silence."
Features Weighs as much as a big amp, so a stout shelf is mandatory; do not use with non-audio devices.
Use Multiple outlets for all components in a system. Ultra 116 includes three-position switches for each outlet that allow for matching to each component.
Value Expensive, but offer commensurate performance and protection.

With all the turmoil and stresses affecting the quality and state of the AC on your incoming power lines, your system absolutely screams for some kind of filtering and conditioning. Filtration of debris like RFI/EMI and the regulation of over/under voltage and sagging/surging current conditions are essential to providing your system with the highest grade of raw material it requires -- the AC power it uses to create the musical event.

Why is high-quality AC power important? Just ask SoundStage! technical editor Doug Blackburn, but be prepared to get an earful. As Doug has explained, an amplifier fabricates a brand-new audio signal from what it "sees." Its job is not to merely make the preamp signal "bigger." Your amplifier actually "clones" the signal it gets from your preamp and then discards the original. That original preamp signal is lost forever after it is used as a template for the new one. This is why the raw material for the brand-new big signal leaving the amplifier, your AC power delivered from your wall, is SOOOOO significant. And more good news: This can happen upwards of six times throughout the audio chain. Have you ever made a copy of a copy of a copy of a videotape, facsimile, or photocopy? Get the picture?

Now that we have made the obvious connection and can take that step further back in the sound-reproduction chain to the AC power at your wall outlet, we can begin to identify the goals of a device we would use to whip that incoming AC into shape. The perfect power-line conditioner (PLC from here on) has one exceedingly difficult job description. It should scrub the incoming power of all deleterious noise while not including or introducing any resonance of it own. It should provide for the complete isolation of each component from the others, so that they in turn won’t pollute each other with any garbage that they might regurgitate back onto the power line. It would be great if a PLC could prevent or smooth any power sags caused by either the momentary demands of an amplifier drawing large amounts of current or other external demands.

Current limiting can happen in two different dimensions, so fighting it is an important goal. First, the PLC must prevent any gradual changes as averaged over time, and it needs to handle those events that are seen as instantaneous current demands, like those imposed by an amplifier. Because your amplifier typically only gets about 30% of each AC cycle to refill its power supply, if the amp is being driven so hard that it is pulling 10 amps on average, the current peaks will be more than three times (or 30 amps) higher. So our PLC must deliver these short-duration current pulses to the amp without limiting them. If the PLC can't pass unlimited current peaks, it may still pass the 10 or 15 amps, but with the current peaks distorted, affecting the amp's sound.

There are two main forms of radiated pollutants that are relentlessly attacking our systems. Radio-frequency interference, which everyone knows as demon RFI, is noise that’s typically very high in frequency. RF signals are generated deliberately by radio stations (and radiated from local transmitters everywhere) and inadvertently by individual electronic components inside your equipment, like power-supply bridge rectifiers and zener diodes. Some critics out there will no doubt dispute that RFI should even be considered a real sonic problem. The case can be made that many transformers are so bandwidth limited that RFI never gets to the secondary windings and that filtering on the DC side is usually considered adequate enough to remove any RFI that escapes the transformer and rectifiers. But for the most part, RFI has been attributed with creating a form of a grainy-sounding hash that we often assume to be part of the inherent noise floor of our associated equipment. That is, until we have heard the results of having it removed. Whether intentionally created or not, RFI is wholly undesirable for your playback system. The second culprit, electro-magnetic interference, EMI, is typically lower in frequency and is often directly heard as an audible hum at 60Hz or some multiple thereof. Things like electric motors and lights (especially those with dimmers) produce this type of noise. Again, completely undesirable.

Another area that requires constant watch is that of the condition, or status, of the AC being delivered to your home. The terms over and under voltage refer to the reference voltage available at any given time, which should be 120 volts. It is not uncommon over the course of a day to find voltage swings ranging from below 117 to over 130 volts. Sags and surges refer to gradual deviations and short-term spurts of power delivery. Sags occur when the line voltage gradually drops to lower than normal (like during times of heavy usage) and then has a like gradual return. There can also be instantaneous sags, like those created when the refrigerator compressor kicks on or your neighbor fires up his table saw or belt sander. A surge is most likely to occur at the end of a brownout or outage period when the power company restores full line voltage to an area that has been running under 110 volts or been without power for some time. The voltage momentarily shoots well over 120 volts on the way back to normal.

Oh yeah, then there are acts of God. A lightning strike on your lines, a downed tree limb hitting the lines or even an accident with a local transformer can cause a serious short-term surge that requires specialized attention to protect our valuable and precious music-making equipment.

With this newfound appreciation of the critical importance of the power you provide to your components, it is no leap to understand that the delivery of clean, stable power provides your equipment with the ability to literally "make" better music. Even those of you out there with the most economic of components will benefit greatly from the effects of conditioning your AC. If budget gear can clearly benefit from this solution, just imagine what killer reference gear stands to realize.

From the beginning

Since its inception in 1991, the original Power Wedge line from Audio Power Industries has been a standard in the high-end community. So why mess with a good thing? Because things change. Both average system size and the number of digital-based products in systems have increased significantly over time. You are now likely to find a separate box for the CD transport, another for the re-clocking device, and yet a third to provide the digital-to-analog conversion -- not to mention the fact that many of today's new digital devices, such as DVD players, can be an order of magnitude noisier than the preceding generation of digital equipment. And did I mention that each component in your system can produce its own noise? Unless those individual noises are eliminated, they will spread to other parts of the system by traveling backward through the power cords. Digital equipment is often the most commonly blamed culprit for such things, but analog gear can be every bit as guilty.

So the old stand-by was no longer good enough. The new Power Wedge Ultra series had to offer the maximum degree of isolation within a system. API’s plan, rather than to simply upgrade the existing line of products, was to take a fresh look at the power-quality issues of today. The result is several new technologies that claim to better achieve the primary goal of all power conditioners, to improve the sound of the system by supplying cleaner, more stable AC power and to protect the equipment from lightening strikes and other catastrophic events.

Hence the new Ultra-series PLCs offer some really significant features. They have separate isolation transformers for each outlet. Separate custom high-frequency output filters are provided on each isolated outlet to attenuate RF noise. The new breed is also larger, built on a regular-sized chassis for maximum shielding against any external radiated noise, providing them with a look much more like a regular audio component. They also have a custom-made, detachable 12-gauge power cord utilizing a new, high-capacity locking connector that allows the option of upgrading to the new API Power Link 311 cord. And to top it all, each outlet has a user selectable configuration for selecting balanced or polarized AC. More on this unique feature just a bit later. Based on the two units I had for review, the new Ultra series PLCs have a fit and finish that will fit in nicely with any rig and complement your other high-end gear.

The new units also sport full RFI-grade internal shielding between each isolated outlet, with each amplifier outlet designed to ensure maximum current flow to high-current amplifiers as well as higher-power capabilities. This helps significantly during brief periods of high current draw while the amplifier's diode bridge is conducting. They incorporate new protection circuitry, including metal-oxide varistors (MOVs) and multiple circuit breakers, as well as Audio Power's claim of unique non-resonant filters designed specifically for audio and video applications.

The Power Wedge Ultra 116 is 17.5" wide x 5.25" tall by 12.5" deep and weighs 64 pounds. It sports nothing on the front faceplate but the stylized API logo. The rear houses ten sockets, with six for line-level equipment and four for amplifiers, which do not utilize any transformers due to the current demands made on them. The six line-level ISO sockets are in a line, each with a three-position toggle switch immediately above and a resetable circuit breaker above each of those. The right-most socket (when viewed from the rear) is rated for 150W (for high-current preamps) while the remaining five are rated for 120W. The four amp sockets are arranged in an over/under two-by-two matrix to their left, with the Neutrik power-cord socket to their left and the main circuit breaker just above that. All very neat, logical, and eminently accessible.

The three fates

The three-position toggle switches above each of the line-level sockets are labeled Normal (up), Float (middle) and Reference (down). In the Normal position, the connection is configured much as would be found in most domestic AC systems, with the neutral line directly ground referenced. In the Float position, the isolation transformers provide a floating output with no reference to ground. In this position, the impedance of the attached equipment determines the neutral/ground reference. In the Reference position, the isolation transformer provides fully balanced AC, referenced to +/- 60 volts. The transformers are also coupled with an individual high-frequency filter for each outlet. This proprietary transformer configuration allows for maximum common-mode cancellation of unwanted signals through fully balanced operation.

A quick call to Kevin Halverson of Muse Electronics, who helped design the new series of API Wedges, cleared up some of the confusion I initially experienced as to how balanced power is achieved. Fully balanced power implies a referencing to both -60 volts RMS and +60 volts RMS to develop the 120 volts we are going to use to power our equipment. In order to achieve this wonderful versatility, special transformers are used with a center tap. In the down, or Reference, position, the attached equipment is now getting 60 volts AC from one tap and a phase-shifted 60 volts AC from the other tap -- which gives you the common-mode noise rejection that you couldn't get from 120 volt and neutral. Very clever.

The Ultra Enhancer 2 is in a smaller metered chassis, just 8.75" wide x 5.25" tall x 12.5" deep, and weighs 19 pounds. It sports six high-current outlets on its rear panel, each one offering filtering but no isolation. The meter, though not backlit, is fairly easy to read and displays the instantaneous AC voltage available. Its full swing travels from 0 to 150 VAC. Not once in my time with these units have I ever seen it move from the dead-on 120-volt position. But I’ve gotta tell you, this seems like an unnecessary waste of real estate. If your power drops below about 100 volts, very few pieces of equipment will even turn on, let alone work. I would think that one would be better served using full deflection on the very large meter to cover, say, 90 to 130 volts, thereby giving it a higher sensitivity to deviations as well. But, hey, like I said, while I’ve had Ultra Enhancer 2, the meter NEVER moved from the 120-volt mark.

The Ultra Enhancer 2’s biggest attribute when used in conjunction with the other API Power Wedge Ultras is its additional parallel filtering and damping. When plugged into the same electrical circuit as any other equipment, the unit will benefit any component plugged into that circuit. Pretty cool, all in all. It is most likely to be at its most effective when used in extremely noisy AC environments or when used in conjunction with high-current components like amplifiers. It can also be used to provide filtered but non-isolated power to an entire system.

The best results from these API products (or any PLCs for that matter) happen when every component in the system is Wedged or Ultra'd. API designs the Wedge and Ultra series to service every component in a system. Otherwise, the benefits of the isolation transformers are compromised. Just think about it: If you plug one component into the wall rather than the PLC, you’ve defeated the purpose of adding the thing in the first place. Don’t overlook your video components if you have a video system integrated with your two-channel audio system. You will need to plan to put everything, including VCRs, DVD players, even your video monitors, on a Wedge or Ultra. That may require more than one PLC for some systems, so plan accordingly.

One more thing that I should make clear. Be sure to tell your significant other that this is not something to use in lieu of an extension cord to plug in your vacuum cleaner or steam iron (no sexist e-mail, please). The 10 amps that such a household device may demand will make short work of the respective isolation transformer -- and is not covered by the limited one-year warranty. This is a point of curiosity to me as most of the other companies whose products I have seen offer a lifetime warranty.

Still...you turn me on?

A slightly modified Linn Sondek LP12 fitted with a Magnepan Unitrac 1 carbon-fiber, uni-pivot-tracking arm tipped with a Monster Cable Sigma Genesis 2000 moving-coil cartridge transcribes vinyl. Ones and zeros are retrieved by a Pioneer Elite PD-41 Stable Platter transport and sent via the new Harmonic Technology Cyber-Link Copper to an Audio Alchemy DTI Pro 32, then on to an Audio Alchemy DDE v1.2 via I2S bus. Both the Audio Alchemy units are powered by the Audio Alchemy Power Station 2, and all three sport the full Channel Islands Audio upgrade treatment by Dusty Vawter.

Both front-ends feed my Threshold FET nine/e preamp which hands off to the Source Component Electronics Harmonic Recovery System which then drives either the wonderful Pass Labs Aleph 3 or the Clayton S-40. All cabling is by Harmonic Technologies. Interconnects are the Truth-Link, loudspeaker cables are the Pro-9 Plus biwires and the power cords are the Pro AC11. Reference speakers are the Von Schweikert Research VR-4 Generation II or the ever-present Acoustat 2+2 ESLs. My listening room is 13' 4" wide x 26' 8" long with a 8' 4" ceiling. Room taming is realized with both Cascade Audio Engineering products and my own home-brew room-taming devices. And, of course, there are lots of Vibrapods, inner tubes and sandbags.

In my system, the new API Power Wedge Ultra 116 is a clear winner. The first thing I wrote down in my notes as I began to evaluate the 116 was that it "cleaned up" a nasty harshness to vocals and other critical midrange voices. Also, what at first may be mistaken as a softening to the upper registers turns out to be just a cleansing effect. Check out Roger Waters’ Amused to Death [Columbia CK 64426] or Crosby, Stills, Nash & Young’s Déjà vu [Mobile Fidelity MFSL 1-088]. The Ultra 116 just strips away layers of aggressiveness throughout the mids and highs. It had an effect that can best be described as a broadband removal of hash. The glare that was, for the most part, always present had been removed. It is kind of like when you are listening to your system and there is some steady and homogenous background noise present -- like when the furnace or air conditioning is running -- which is aurally blended into and thereby becomes part of the music, and is then removed.

The noise floor dropped seemingly an order of magnitude. Recorded silence between movements in symphonic works and rock pieces where the band stops and then restarts actually sounded like silence and not some aberrant low-level rushing sound. Listen to the quiet passages during the breaks in the title cut to Stevie Ray Vaughan’s Couldn’t Stand the Weather [Epic FE 39394] or Respighi’s Pines and Fountains of Rome [RCA LSC 2436], for example. Everything just emanated from a darker fabric. That fine-grain noise that was omnipresent, slightly akin to white noise, was gone.

The Ultra 116 also had a profound effect on the apparent speed and depth of the bass. While at first this was perceived as a slight level reduction, upon extended listening, it revealed itself to actually be a cleansing of the muddiness and congestion that was apparent previous to the insertion of the Power Wedge Ultra 116 into my system. Check out any Walter Becker bass run on your favorite Steely Dan album or the plucked double-bass part from an orchestral piece. Now those bass lines, while seeming ever so slightly more restrained, were much easier to follow due to their newfound definition. There was a greater sense of ease and much, much more detail. The sheer resolve the 116 provided in the bass lines was readily manifest. There was a renewed sense of body and detail in the under 60Hz range, and this is always a good thing.

Staging and imaging just grabbed me now. Images were layered much better, offering more dimensionality. They were much more vivid in their respective space, floating deeper and with a better sense of body. Try "The Invasion" from John Williams’ soundtrack to Seven Years in Tibet [Mandalay SK 60271]. The space and sheer grandeur of the choir on The Turtle Creek Chorale’s Postcards [Reference Recordings RR-61] is equally telling.

The difference in the dynamics department was anything but subtle. Micro-dynamic shadings were more vivid. Listen to Mark Knopfler as he sings at a minute into "Fade To Black" from Dire Straits On Every Street [Warner Bros. 26680]. The breathy "P" sound created by the expulsion of air from his mouth when it hits the microphone just explodes into the room. Seemingly indiscriminate background noises were now revealed to be the sounds of people moving in the hall or whatever they really were. The sheer difference in volume in swings from quiet to loud was larger as well.


I played with all the toggle-switch positions, but time and again, kept coming back to Reference. In my experimentation, the turntable seemed to be the most insensitive to which position the switch was set to, and the digital front-end (all three pieces) seemed to be the most. My Threshold FET nine/e preamp and Harmonic Recovery System lost much of their transparency when switched to anything other than Reference.

With the switches of the Ultra 116 set to the Float position, backgrounds were nice and quiet, but there just wasn’t the same sense of space and detail they served up in the Reference mode. Instruments had less of a "there" presence and the subtle shadings were more difficult to establish. In the Normal mode, besides sharing many of the same attributes as the Float mode, there was an apparent slight elevation in the noise floor. Some of the grayness seemed to find its way back into the system, offering a broadband effect similar to that of hanging a light veil over the sound. Play with the settings for yourself by all means, but I feel confident in just recommending that you leave the bloody thing in the Reference position and quit worrying.

Taking my own advice, I unplugged the power supplies for my eight-foot-tall ESLs from the unconditioned wall sockets and fed them from the little Ultra Enhancer 2. Zippidy do-dah, what a sweet effect this had -- better-defined midbass and a new clarity to the whole perspective. I do have to say that adding the $649 Ultra Enhancer 2 to my system, while admittedly providing a slight degree of enhancement to nearly all the aforementioned effects, brought relatively little to the table by  comparison. The greater overall transformation wrought by the Power Wedge Ultra 116 alone was considerably more significant in my system.

In the end

I cannot say how these wonderful little power scrubbers, stabilizers and guardians will work with your system, on your power grid and with all of your components. As you would expect with this hobby, EVERYTHING makes a difference, and power conditioners are no exception. Given the opportunity, you should try several different designs and select the one that sounds best in your system. While the results I experienced were very significant and positive, other PLCs may work better for you. I am sorry to say that I had no other PLCs on hand for direct comparison, but I did wring out the Ultra 116 to the utmost.

You should bring these bad boys home and let them do their taming act with your power and see if they light your fire as they did mine. While $1499 for the Power Wedge Ultra 116 alone (or $2148 when teamed with the Ultra Enhancer 2) won’t qualify as cheap in anyone’s book, it isn’t outrageous. Given the nature and degree of the transformation they wrought in my system, the Ultra 116 alone or with the Ultra Enhancer 2 more than justifies the price of admission.

...Greg Weaver

Audio Power Industries Ultra Power Wedge 116 and Ultra Enhancer 2
Price: Power Wedge Ultra 116, $1499; Ultra Enhancer 2, $649
Warranty: One year parts and labor

Audio Power Industries
2624 S. Rousselle Street
Santa Ana, CA 92707
Phone: 714-545-9495
Fax: 714-545-4607

E-mail: info@audiopower.com
Website: www.audiopower.com

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