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AVA Omega III EC PreamplifierThe $ensible Sound Manufacturer: Audio by Van Alstine, 2665 Brittany Lane, Woodbury,
MN 55125; 651/330-9871 http://www.avahifi.com/ info@avahifi.com This review focuses on Audio by Van Alstine's new solid state Omega III EC ("enhanced capability") preamp that has recently replaced the Omega II in the AVA preamp line. Included as a reference is my venerable AVA Super PAS Omega preamp, which is similar to the current line of AVA PAS-based tubed preamps, which sport tube gain stages and solid state output buffers. To do such a comparative review of AVA preamps is a sort of deja vu for me. Several years ago, I did a similar comparative review of earlier AVA solid state and tube preamp designs, namely the solid state Super FET 5 and tube Super PAS Two. I know quite well how AVA's tube designs have evolved since then, because I have lived with and enjoyed the Super PAS Two's development into the Super PAS Omega via the upgrade process; however, I was quite interested to see how far AVA's solid state designs had come in the intervening years. One very obvious change is that AVA is now doing its own sheet metal design and construction. No longer is an old Dynaco or Hafler chassis required. No longer is the circuit layout constrained by the physical limitations of someone else's chassis. The new Omega III with its AVA metal work has an open layout, widely spaced jacks, and plenty of room on the faceplate for all of the controls. The Omega case is all black with a slimline profile, although not so slim as to make it difficult to work the controls. The black metal knobs have bold white position indicator marks that are quite visible, even from several feet away, and all the controls are clearly labeled. Aesthetically, the Omega III EC is a major improvement over previous AVA preamps using other manufacturers' chassis, and although one still cannot call it elegant "high end" (read expensive) styling, it is functional and looks good in my equipment cabinet. Speaking of controls, the Omega has a multitude of them, indicating its versatility. Front panel knobs and switches include volume, balance, bass, treble, tone control defeat, input selector, stereo-mono push-buttons, tape monitor, EPL, mute, filter, headphones, and power. The function of most is obvious. Exceptions include the mute push-button, which does not truly mute the output but instead reduces it by about 20 dB-you can still hear that the system is operating, but at a much lower volume, reducing interference with say, a phone call. The EPL (external processor loop), consisting of a pair of input and output jacks, enables you to switch an equalizer, subsonic filter, or some other similar device in and out of the circuit without having to manually plug and unplug it. You can also do this with the tape in and out jacks but you have to give up your tape monitoring capability. AVA points out in the owner's manual that the simplest use of the EPL is for channel reversal, where the cable from the left EPL in jack goes to the right EPL out jack and the right input jack is plugged into the left output jack. The filter control affects primarily the subsonic bass and high trebles and is useful in reducing noise and hiss on poorly recorded tapes or TV, FM, or AM broadcasts. The headphone jack is connected to a small, low power amp that will drive medium and high-impedance phones. The stereo-mono push-buttons provide the normal stereo output, left signal to both output jacks, right signal to both outputs, and a mono signal to the outputs. The mono output can help reduce noise on weak FM stereo stations. All the controls have a solid feel and are easy to use. One control that is present on my old Super PAS but missing on the Omega III is the stereo blend control. This control does what the mega's stereo-mono push-buttons do and, in addition, offers three degrees of stereo separation ranging from maximum (normal) down to modest separation. Until recently, when I set up an abbreviated home theater system (standard stereo left and right channels, no rear channels, and the TV itself providing the center channel), I had never used this stereo separation feature. But with the home theater setup I found that reducing the separation without going to full mono was very effective in achieving a realistic sonic image that matched the picture. In the normal stereo mode, the separation was just too much. For example, highly localized sounds associated with action at the far left side of the picture came from the left speaker-well outside the picture-and were quite artificial. Reducing the separation using the Super PAS's control resulted in much better matching of the audio and visual images, improving the realism considerably. This control is not standard on any of the models currently in the AVA preamp line, but according to AVA, minor circuit modifications can be made to provide this blend feature if an owner desires. The Omega III's selector switch controls eight pairs of input jacks located on the back panel, which should be adequate for even the most complex system. If the phono board is installed, it is wired to the jacks connected to the Special position of the selector switch. If the phono board is not installed, the Special jacks serve as another high level line input. There are two pairs of output jacks plus tape and EPL out jacks. Three switched AC outlets are also located on the back panel to power lower wattage units such as a CD player or turntable but not a power amp. Corrosion-resistant gold plating is found on all the jacks and many of the switch contacts. The quality of the circuit boards and components is very similar in quality to the Super PAS, which is to say, excellent. The Omega does not use discrete transistors in its gain stages opting instead for integrated circuit op-amps. This is a major "no-no" for many high end manufacturers but not to AVA, which has successfully used ICs in some of its preamps for years. There are some circuit options that the owner can choose in order to tailor the Omega III to his or her needs, including a phono section ($90) for those who treasure analog sound or have large record collections, and tape buffers ($90) for those who tend to have a tape recorder connected to their preamplifier. The review unit came with both the phono and tape buffer options. Sonically, the Omega III represents a noticeable step ahead from some of the solid state AVA preamps from the 1980s. The old Super FET had a bold, up-front, vivid presentation. It was highly detailed, due in part to the way the trebles were subtly pushed forward. It had great soundstage width but proportionally less depth and body. Initially, it was a fun preamp to listen to, but in longer listening sessions, it called attention to itself and could be a bit artificial and fatiguing. While not a bad preamp, I felt it was just not as good as the Super PAS Two to which I compared it. Not so with the Omega III. It provides the detail resolution of previous solid state units but the soundstaging and imaging are improved. The unit never calls attention to itself but instead gives the impression that it steps out of the way and lets the music flow. This natural presentation is never fatiguing, indicating improved trebles. The midrange is very neutral and the bass is extended and powerful. In comparison to the Super PAS, the two are far more similar than different. The only real difference I observed, albeit quite subtle, is that the attacks or leading edges of the notes on the Omega III were a bit sharper, giving the impression of "quickness" or "crispness." Initially, I interpreted this crispness as enhanced detail resolution by the Omega. However, on careful listening, the detail resolution of the Super PAS appeared to be fully comparable to the Omega. The 3-dimensional presentation that I have come to appreciate with the tube AVA preamps and found a bit lacking in some previous AVA solid state units is definitely present in the Omega III. While I don't listen to analog recordings much any more, I did briefly try the phono stage installed in the Omega III. I found it to be very quiet and the resulting sound to be excellent, fully comparable to my best CDs. I did cheat a bit in that I used one of my best records-a Mobile Fidelity half-speed remastering on heavy Super High Definition vinyl of Adrian Boult's EMI recording of Elgar's Falstaff. Only a few pops and ticks reminded me that I was listening to analog, not digital. The phono stage should serve analog enthusiasts very well. A side comment is needed here to report on the turnoff behavior of the Omega III. Most AVA preamps of the past have been notable in their quiet, noise-free turnoff. One exception has been my Super PAS Omega, which has nonstandard chips in the output buffers that do cause a modest "pop" on turnoff. This is the nature of my particular unit, not normal production units. The other exception now is the Omega III, which does have a turn-off transient that is quite audible if you turn if off while the power amp is on. The AVA instructions for the Omega III as well as the Super PAS clearly indicate that the preamp should be turned on first and off last, after the amp has powered down. This will prevent the transient from passing on to the speakers. This is a very wise procedure for all audio systems. But, for most preamps I review, I turn the preamp off while the power amp is on just to check for any untidy behavior. When you have a sudden power outage, you can't follow the standard turnoff procedure and must rely on the ability of system's components (lack of turn-off transients, muting relays, fuses, etc.) to prevent possible damage. Mechanically, electrically, and sonically the AVA Omega III EC is a real winner. Its mechanical construction may not compare with that of other high-end units costing four or five times its price, but it is fully adequate for home audio usage. Its aesthetics are a big improvement over previous AVA units. One might argue that ICs are the cheap way to go. My response is that the proof is in the sound. If ICs can offer really good sound then they certainly represent a sensible approach, especially if they reduce the cost, too. And in the case of the Omega III, ICs provide excellent sound. At $649, plus a mere $90 extra for an excellent phono stage, this versatile preamp has got to be one of the better bargains in audio. It is what $ensible sound is all about. But what if you don't need all the features on the Omega III EC? What if you have to rob a bank to get enough money to buy it? My recommendation is to give up your life of crime, go straight, and get the SL (straight line) version of the Omega III. It doesn't have tone controls, reduces the inputs to a "mere" six, has no EPL, and has a slightly narrower case. It uses the same audio circuits as the EC version but is priced at $449 wired and $349 in kit. And if you are on a really tight budget, you can go Real Basic and get the Omega III RB for $399 assembled or a remarkable $299 in kit form-a high end preamp for $299! The RB offers only two inputs and has other cost saving measures, but retains the same Omega audio circuitry. I have not seen or heard the SL and RB versions of the Omega III but I suspect they are the mechanical, electrical, aesthetic, and sonic equals of the EC version, differing only in their features and versatility. Overall, I found the Omega III to be a refreshing new audio product and a very positive statement about the ability of audio manufacturers to provide excellent quality-and value. - KMD My reference preamp for many years has been the AVA Transcendence Series Two (now discontinued), with discrete audio circuitry that in my case was installed in a Hafler DH-100 chassis. I have auditioned many preamplifiers over the years, including several units highly beloved by the audiophile fringe, and still have not heard one that would lead me to give up my trusty old Transcendence. The Transcendence was discontinued a couple of years ago or so when the Omega II was introduced. However, plugging the Omega II into my system was something of a disappointment. Although it had excellent detailing ability, it did not seem to handle high frequency stress, such as sibilants, with the aplomb of the Transcendence. My overall take on the Omega II was that it was a pretty good preamp for the price, but that it was clearly not a replacement for the Transcendence Series Two. AVA pulled the unit from the market before we finished our review, so we waited patiently for the Omega III. I spent several days with the unit before shipping it off to KMD, enough time to be impressed. Gone was the "silvery" coloration I had heard on the Omega II. Sibilants did not seem to tax the circuitry. Although I seemed to miss just a touch of the warmth of the Transcendence, I am not sure whether that warmth is not itself a slight euphonic coloration. As another point of sonic triangulation, I have also listened to a new and very excellent preamplifier from R.E. Designs that goes for $1,200, which we will review in detail in a future issue. For now, suffice it to say that on sonic grounds, the Omega III is in the same class, and for $550 less, offers much more versatility. My prediction is that the R.E. Designs will become the darling of some factions of the "high-end," while the AVA Omega III will be ignored or dismissed. Go figure. Please note that this is not to disparage the R.E. Designs unit, which is a remarkable preamplifier, it is just an attempt to put into perspective some of the foibles of the audio hobby. But enough politics-back to the unit at hand, the AVA Omega III. The construction quality and design is really excellent. AVA did a really nice job of figuring out what features could be incorporated into a preamplifier and then wrapped everything into a really sturdy and attractive package. The design integrity and construction quality of the Omega III put to shame many popular preamplifiers that sell for more (and have big advertising budgets). The array of control features and optional circuitry ($90 for a phono stage is a steal in this day and age!) put some sweet icing on a tasty cake. - KWN Excerpted with permission from Issue #57, Spring 1996, of The $ensible Sound. Subscriptions to The $ensible Sound are available for $29 per year (6 issues) by check to 403 Darwin Drive, Snyder, NY 14226 or through Visa/MC by phone (800-695-8439). You may also purchase a set of all available back issues (currently 50+ issues) for $89.00, shipping included.
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