Legacy Audio i.V4 Ultra multi-channel amplifier Review

Comparison to class A and A/B

How can I make the statement that the i.V4 Ultra has bettered every tube and Class D amp I have used in 14 years if I did not do a direct comparison? The answer is fairly straightforward; I have elevated the quality of the amplifiers I use over time, moving from one reference to a new one, while my source, the Small Green Computer sonicTransporter and the SONORE Signature Rendu SE with systemOptique, has remained more stable. The Pass Labs XA200.8 monos were the best solid-state amps I had used to date. Note that I have kept several speakers for about eight years, which is a lifetime for me! I have heard the King’s Audio Kingsound King III and Legacy Whisper DSW Clarity Edition with many amps in a variety of configurations. I had previously built more than a dozen systems with the XA200.8 monos. They were my reference, and they made both of these speakers perform at their best. I do not believe that bringing back any of the previous amps would make them perform on a level with the i.V4 Ultra. When I have revisited previously owned gear, it ends up being a disappointment, and the fact that I have moved on to better sound is reinforced by the experience. What is to be gained for myself or the average audiophile if it takes better than $50K and hundreds of pounds in components to have a chance at bettering the i.V4 Ultra? Is that a worthwhile pursuit? Perhaps for some with much deeper pockets and a younger back, but not for me. I’ll leave what I consider a low probability search for a much finer class A or A/B to someone else. They can knock themselves out wrangling behemoths in an effort to eclipse the likes of the Legacy amp.

Clearly superior

It does not take long to hear the superiority of an amp when you know what to listen for, and in this instance, I worked through dozens of pieces of music that I have collected into my reviewing playlist. Here is a tip for those who lack direction in assessment of gear; it is not required to hear entire tracks or cuts. Even a segment, a minute or two, from an intimately known piece is sufficient to reveal the fundamental differences. When dozens of such pieces are so affected, then the conclusion is sure: the amp has better resolution, impact, transients, headroom, quietness, etc. Sometimes an amp has a couple of these qualities in abundance, and it requires more careful sifting through the music. But, in this case the outcome was obvious, not questionable. I could come up with no parameter in which the i.V4 Ultra was not superior.

It should be remembered, however, that while the parameters of performance can be assessed in a straightforward manner, the emotional impact, whether one connects with the component in terms of how the music appeals to the soul, is also critical. For that reason, longer term listening is necessary to reinforce that the changes and benefits are indeed desirable. I do not simply put the amp through the paces and declare a winner. I combine this with extended listening to see if the improvements are indeed more pleasurable. Most of the time they are, and the i.V4 Ultra presented itself like all superior components — the longer I listened to it, the more desirable it became, thus confirming the benefit of the sonic advantages.

A quick take, repeated multiple times with different sets of music, is sufficient to make a firm conclusion in regard to performance. However, it is not sufficient to answer the question of whether the amp will deliver more enjoyment over time. For that answer I turn to listening sessions of full playback of pieces, with particular attention given to whether I feel fatigue from harshness over a longer listening session of 1.5-2 hours, or whether the amp is unexciting such that I feel like falling asleep. One of the most telling aspects of the difference between these other genres of amps and the i.V4 is the preternatural quietness and nonexistent noise level. Noise level dictates how much grunge will be heard when an older recording is played back. Until the arrival of the i.V4 Ultra I had despaired of higher-level playback of my oldies. The XA200.8 was good, and I thought perhaps about as good as it can get in terms of banishing amp noise and allowing the signal to shine through. The i.V4 Ultra seems to be an order of magnitude better when it comes to adding no noise to the signal. The other bugaboo for these non-class D amps is sheer distortion associated with powering music at higher levels. When the distortion is combined with older, softer recordings, it makes them sound thin, harsh, and unforgiving. That is why I was frustrated listening to my old favorites; they didn’t sound welcoming.

The i.V4 Ultra can be jacked up to an intimidating level with no perceived distortion and no noise being added. I know fans of Pass Labs and other classes of amps will rage against this discussion, demanding it be known that these others do not add distortion. If you hear the i.V4 Ultra, you will understand — completely. As an example, when I listen to the low frequencies as found in “Royals” by Lourdes or “Flight of the Cosmic Hippo” by Bella Fleck, the 15” drivers’ action on the Whispers seem as tight and precise as 6” woofers in bookshelf speakers, but with the benefit of lower frequency extension.

It is a singularly thrilling experience to hear an electrostatic speaker that you thought might be maxed out in terms of cleanness driven to a more resolving performance. People think that because they have put a Bryston or McIntosh amp with a Maggie or an old Quad that they have something special. You have only begun to experience the riveting precision of a panel speaker! Put the i.V4 on your speakers and you’ll start to hear serious panel magic! It is becoming well known that class D amps do not have difficulty driving lower impedance speakers, but historically they have been white or clinical sounding. I can hear the rebuttal now, “class D will never have the warmth and fullness of class A or tubes!” Wrong. I’m hearing it.

At one point during the review, I put my inexpensively restored Ohm Walsh Model F omnidirectional speakers into the room with the i.V4 Ultra, even though using only two channels of the amp. Prior, I had been using the Kinki Studio EX-M1+ Integrated Amplifier, but the speaker was indistinct, even though I fixed its primary problem by removing half the dense batting in the bass cabinet. The thing that saved the performance of the Model F in terms of worthiness to be heard was putting the i.V4 Ultra with it. The old full range driver finally had some precision to give me, and was not as sloppy as with the Kinki Studio, even though the EX-M1+is a fine integrated amp.

The shocker – tone color

The next point I am going to make will sound contradictory and, in the minds of some, impossible. The i.V4 Ultra not only has exquisite detail, it is also exquisitely and tonally pure. It brings a sense of the ideal to each voice’s and instrument’s tone and reduces the incidents of sharpness in some notes that other amps project. How can a switching amp do this? I don’t know how, but it is surprising when class A or A/B solid state amps like the XA200.8 and the EX-M1+ sound rougher and less pure.

It seems as though the precision of the i.V4 Ultra aids in the perception of proper tone. Notes are not as fuzzy as with class A and A/B amps I have used, not to mention the relatively ragged notes that most tube amps have created. With this amp notes are emitted as solid, precise, and without sloppiness. A listen to Brian Bromberg’s “Elephants on Ice Skates” confirms the precision, but it is the unwavering correctness of color and tone that impresses. What’s more, the content within the note, the miniscule fluctuations that last split seconds, are revealed cleanly. I have not heard such from tube amps at all, and not much from the solid-state ones I have reviewed. Similarly, as the background is so quiet, the decay of notes is extended from what would be expected of music coming from a digital source. There is a sense that the amp has terrific power, but is not heavy-handed. Class A and A/B amps sound relatively plodding in comparison, as though notes are not hit, but wallowed in, as though struggling to get entirely off one note before making another, resulting in more of a merging of notes. The differential design of the i.V4 Ultra and a high damping factor of 750 average from 20Hz-1KHz make it sound obviously fast and hard hitting, especially in the bass.

Speakers matched with the i.V4 Ultra nicely show not only their relative cleanness, but also their relative warmth. The coolest sounding was the Vapor Joule White, and then the King III, with more warmth attending the Aspen Acoustics Lagrange L5 MkII, and the most warmth found in the Whisper. Why is this so? I suspect the primary reason is the amount of bass surface radiating area and frequency extension. While the King III has more surface area than the L5 MkII, the latter has a powered subwoofer that reaches far deeper. No doubt the amp contributes to the sense of warmth of a speaker, but even with the cooler, some would say brighter, speakers, I did not sense an overabundance of brightness or an imbalance of energy top to bottom. The attributes of the design seemed to be enhanced, not reworked and steered. In this way, the i.V4 Ultra is the most neutral amp I have handled, and that neutrality complemented the speakers by not editorializing or masking. Neutral in this sense is clean and clear, like the air in a room that is transparent, versus attempting to see through a haze.

Speaking of air, in the past when playing pieces of music recorded at lower levels it has been problematic to play them back at higher listening levels, as the system noise, a large part coming from the amplifier, has been irritating. Music with dramatic pauses (silent passages) can be disturbed by amp hum or hiss through the drivers. Most amps are not absolutely quiet, they are relatively quiet. In an average room one may not hear the noise, but in my custom listening room, which has a noise floor about 8 dB lower than the average quiet room in a home, any amp noise is heard. I have gotten used to most amps having their own telltale noise. Not the i.V4 Ultra! Black background is an appropriate description for passages that are supposed to be quiet, even though there is a signal. The i.V4 Ultra excels at such things. I strongly recommend that listeners to very low energy music or pieces that are recorded at lower levels and are thus prone to more amp noise if turned up audition one of the amplifiers in the i.V Ultra line.

Layering of the performance is noticeably superior with this class D amp. By layering, I mean the ability to hear multiple streams of instrumentation or voice as they overlay each other. These usually get confused due to the amp’s inability to cleanly render each of them, making the nuances of each instrument’s or voice’s contribution difficult to distinguish. The layering the i.V4 Ultra produces is exemplary, allowing my mind to think though several contributing threads to the performance simultaneously!

Examples of all these features — precision, tone, air and layering — are heard in one of my cherished works, Reflection on a Decade by Checkfield, recorded in 1997. There is a great deal going on in a piece such as “Africa” or “The Good Brown Earth,” but it happens not rammed together, but as lilting layers crossing each other. The i.V4 Ultra defines each layer so it can be appreciated. I adore what this amp does for precision and tone, as well as what it does not do (mask). It is as though the Legacy amp has additional powers of magnification available to it that escape even fine Class A and A/B amps. It simply can resolve non-audiophile music in a superior fashion without making hash of it.

Recalling my pre-reviewer days, when having fun in listening was as important as having a correctly rendered experience, I pulled out some decidedly non-audiophile-approved pieces such as George Benson’s While the City Sleeps (1986) and Gino Vanelli’s Brother to Brother (1978), both of which discs I have loaded onto the sonicTransporter and Signature Rendu SE. The i.V4 Ultra lowers the noise, creates more air, and layers the individual contributing elements such that the entire piece breathes, a description that analog lovers use to distinguish their preference of vinyl to digital. This amp allows digital sources to breath!

Are these observations in regard to the i.V4 Ultra universally true? I think so, but I was reminded of how one still has to tune a rig in order to maximize its potential. Toward the end of the review period, I received the parts necessary to convert the PureAudioProject Trio15Horn1 to the formidable Quintet15 Horn1 (on review). I have moved along in changes to the speaker, starting with impressions gleaned from the stock speaker, and introduced changes, including an upgraded Mundorf Evo oil-filled capacitor in place of the stock cap, and upgraded wiring to the horn. I am in the process of assessing these changes currently.

One of the changes inadvertently gave me a bit of trouble. Prior to introducing a second iV4 Ultra in a novel multi-channel mono configuration (remember, do not join outputs as this is a differential amp, and doing so may cause damage!) I had swapped the BAV (Belden Audio/Video) Power Cord with a Clarity Cable Vortex Power Cord. In the Iconoclast by Belden Cables review I averred that there can be a tick of improvement of the Iconoclastset with certain speakers if a slight mixture of Clarity Cables, typically a power cord, is introduced. Having done that, later I added the second amp, but forgot that it was using the Belden power cable.

As I began to listen to the system there was a disruptive, bothersome imbalance in the center image for which I could not account. The bass seemed not quite even, the center image’s midrange was less on the left side, and there was a disturbing variance in the presence of the treble between the left and right speakers! The disparity was so strong that I could not stand to listen to the imbalance, but had to find the cause. The speakers were positioned properly, the crossovers checked out, the wiring was perfect. Yet, when I played a voice test track to assess “Left… Right… Center,” both the output and the tonality of the horn on the left channel was noticeably duller and had less output. As a learning point for us all, I share that my attention was drawn to the left speaker as the problem, because the right speaker seemed cleaner with more sparkle in the treble. In reality, both channels were acting in accord with the system as it was set up.

Finally, it struck me that I had two different power cords on the amps, a variance that definitely can cause such an issue! Replacing the remaining Belden Power Cord with the Vortex, the system snapped into focus, the center image larger and whole, spanning the appropriate gap between speakers, the bass more linear and even between the towers, and the tonality evenly distributed. This was confirmed instantly when I replayed the voice test track. Every aspect that had been different — output, tonality, resolution— now was a perfect match to the right speaker. As expected, music was played back properly as with a system set up correctly.

Can a power cord do such to an amp and entire system? Absolutely! My faux pas is a great way for you to learn the power of power cords. Use two different models on your monoblock amps and see how it skews the system, and when a matched pair of PCs is used, hear how the rig reorients to proper sound qualities! Also, confirm that what you are hearing is in fact happening by employing a voice test track as I did. This is likely the cheapest, easiest way to discover for yourself the efficacy of finding the right power cord for one’s system. (I still recommend that cables be assessed in sets, not as a mixture of brands/models.) The i.V4 Ultra was splendid in this mishap-turned-learning-session, for its impeccably honest performance allowed me to learn not only what was wrong with the setup, but proved that power cords are critical to performance.