Legacy Audio i.V4 Ultra multi-channel amplifier Review

What these amps were sent to do (And another thing they were not sent to do)

First, what were these amps not sent to do? They were not sent to conduct a comparison similar to the one that I did ten years ago for my article at Dagogo.com, “Audiophile Law: Thou Shalt Not Overemphasize Burn In.” I told Legacy Audio Technologist Brice Auxier, who has been terrific in arranging and managing the loan of the amplifiers, I had intent to conduct comparisons such as I did in that article. He thought it was a great idea. It was a great idea because there is too much implementation of poor methods in the audiophile community. I put in the time to determine what does and does not actually propel systems to higher performance, and I work with methods that are efficacious, regardless of the popularity of questionable methods.

In that initial article, I wrote about how I learned from actual comparisons that paying attention to (attempting to work with) such things as break in, warm up, and the like is a waste of time. These variables conferred no changes sonically to equipment, regardless of the insistence of emotional audiophiles. In my updated comparison, recently published, I used not five variables simultaneously, but eight: “broken in” power cord, interconnects, speaker cables, and i.V4 Ultra amp, amp stand, isolation devices, weights atop the amp, and warmed up amplifier versus none of these conditions. As it involved general testing and has no relevance to any particular feature of the i.V4 Ultra, I shared the results in a separate article, Audiophile Law: Burn In Test Redux.

The raison d’etre for these four-channel amps to be here was for an active setup of the Whisper DSW Clarity Edition, to assess this prodigious speaker’s performance with six channels (8 if subs are employed) in use with the Legacy Wavelet, which incorporates preamp, DAC, processor, and room control. This was an exciting moment for me, as I previously had glorious experiences with the Whisper, and have been engaged in aggressive system building with the i.V4 Ultra, as seen above. The climax of the review was using the i.V4 Ultra with the Wavelet and the Whisper speakers. One might expect that this system would have a high degree of synergy.

I cannot stress enough how exhilarating the experience has been using the i.V4 Ultra as an amplifier driving a variety of speakers of different genres, and how perceptually perfectly it has done so! This is easily my favorite amp of all time. I have owned many amps of different iterations, and reviewed many more. I would not trade the sound the i.V4 Ultra gives me for any of them. Have I made it clear enough yet? Class D is now formidable, a monster genre on the move to annihilate the other classes over time. Get comfortable with the idea that you will eventually be using a class D amp, not because of lack of choice or a weak back, but because your ear has been bent toward it, even if reluctantly. If sound quality really is the most important thing, you will be using a class D amp in the nearer future. Deny it if you will, but remain open to the possibility that you could be wrong. Drag your anchor if you must, while the world sails on.

Of the speakers used in this review, the pinnacle, the most powerful, dominating speaker system in terms of creating massive scale and overwhelming dynamics with the best frequency extension, especially with the Legacy EXTREME XD Subwoofers, has always been the Whisper. In terms of speakers I have on hand, the King Sound King III (see review) is large scale, the PureAudioProject Trio15 Horn1 has striking immediacy, and the new Aspen Acoustics Lagrange L5 MkII (review forthcoming) has ineffable beauty. None roll so much of the big event transducer into one package as the Whisper. When I set these speakers up, I know the room will be pressurized as much as I wish and completely without strain, the lowest of notes will be clear, the excitement of big band, orchestra, or large acoustic performances will be rendered palpably, and I will know I have experienced an impressive system.

Active/passive modes

I have spent a fair bit of time discussing in general the result of using other passive speakers with the i.V4 Ultra, so I will not spend as much time on that in regard to the Whisper DSW Clarity Edition. Over the years I have been able to improve the performance of the speaker’s bass, which looks like it could blow doors off rooms, but is more of a gentle giant. Though the pair sports eight 15” woofers, they are positioned precisely to reduce off axis (side) dispersion, allowing placement of the Whispers closer to walls. Indeed, I have often placed them less than two feet from my side walls without discernible negative effects.

The major improvement brought by the i.V4 Ultra in terms of bass was not a sense of deeper frequency extension, as I believe the XA200.8 monos were as good in that respect, but chiefly in beauty and precision. I very much enjoy hearing bass lines rendered distinctly in music, and when they are rounded and merged to the point of being less distinct, I am not happy. The i.V4 revealed tauter bass performance in whatever music I played. It is easy to achieve impact with eight 15” drivers operating passively, but difficult to achieve coherence like a pair of 15” drivers. The resolution, even at lower frequencies, is a selling point of the ICEedge technology, for the Whisper had cleaner bass than I have achieved with many typical tower speakers, especially ones with passive radiators. I think the bass was as clean as the 11” Audio Technology drivers of the Vapor Audio Joule White. That has not happened historically with tube amps and even fine SS amps. The i.V4 Ultra distinguishes itself in so many respects, and the fine, impactful bass/LF is a pleasure.

The Iconoclast by Belden Cables are a perfect choice for this exceptional amplifier. Never has the Whisper carried such resolution and warmth at the same time. Usually, the speakers lean one direction or the other, such that I have on occasion with particular equipment resorted to mixing brands of speaker cables on the three sets of input posts, bass, midrange and treble. The ribbon drivers are at times forward with harsher music, but with the i.V4 Ultra there simply is no excess of presence. The extra resolution afforded by the amplifier turns a treble note into an isolated micro-event, with happenings within. As such, the treble is less laser and more arc light; they both have intensity, but the degree of focus is the difference between illuminating and cutting.

With each improvement in amplification the choice of Bill Dudleston’s drivers for his speakers is confirmed. What might appear to the eyes as a disparate collection of drivers that can’t work right become more and more seamless, and the i.V4 Ultra draws them closer than ever, but does not make a mish-mash. Can such results be improved upon? Years ago, when I first compared active crossover results with the Wavelet in passive speaker mode, I concluded that all things equal (or as close as possible), the active setup was superior. But, when components were changed out in either system, the results were not consistent. With particular sets of components, the passive setup could outshine the active setup. Now, years later, with an amp I would not hesitate to call extreme, I am returning to that comparison so as to not anchor to older impressions.

Active operation

I did not set up the Legacy Audio Wavelet with the pro quality XLR cables supplied by Legacy that are typically used for the speaker, but used the three sets of Iconoclast by Belden 4×4 Generation 2 Ohno CCC XLR Interconnects and associated SPTPC (Silver Plated Tough Pitch Copper) Speaker Cables, both the top models. I had been working with the Iconoclast cables while finishing up their review, and the Whisper was the final speaker, so the cables were in place for passive operation. The predominant reason was for consistency in assessment; the proper comparison is not to switch out cables, but use the same ones even though the speaker mode changes. Besides, this assured the highest quality sound from both modes of operation.

The first experience that met my ears when I turned on the system with the speakers in active mode was that there was something different about the setup, even though no music was playing. I was not hearing overt noise, but the sense that the energy level had changed was nearly palpable, almost like a subtle pressure wave. The stillness factor was disturbed, the passive system being inert, but the active system seeming to have a kinetic potential. Even so, I could not detect any overt noise. It was nearly as distinct a feeling as entering a different room. I doubt that most people would have that experience, given that my room has about 8dB lower ambient noise level than most quiet rooms in homes. There seemed to be some very low-level event associated with the change from the crossover, and I suspect it is due to increased gain. By the third session, the turn-on sequence and feel of the system was comfortable, without the sense of it being different from the passive setup. It will be a curiosity to return to the passive setup and see how that strikes my senses when it is first started up.

The first moments of hearing the speaker were also distinctly different, primarily due to the leap in resolution, increased headroom and increased dynamic capacity. There were several things in terms of the components changing in this setup, many of them occurring in the Wavelet, which handles the functions of DAC, preamp, processor and room correction. This was not expected to be an apples-to-apples comparison, as the entire management of the signal from DAC through to amplification was altered. Therefore, with this setup I cannot speak in an absolute sense of which is better, active or passive.

Audiophiles should recognize the inherent problems in drawing firm conclusions between active and passive systems, but often do not. I see recurring discussions on forums of individuals who either recommend an active speaker, or state that they switched to an active speaker of a different brand than the passive. Nothing can be known with certainty in regards to such cases, except that the owner prefers one or the other. It is misguiding to suggest that such a comparison proves that active speaker systems are superior. The systems I am making with the very same speaker are closer to the kind of conditions necessary to make a proper evaluation. It should be obvious that the potential exists that any given passive speaker may outperform any given active speaker. I appreciate that fact when I use the i.V4 Ultra with passive speakers. I do not believe a smallish active monitor would outperform a speaker such as the Salk Audio SS 9.5 (reviewed) with the i.V Ultra amp. Only comparison would tell definitively, but it is an unjustified perspective to give the nod to the active speaker without a comparison. Yet, such declarations are made regularly, which shows how far from a supported opinion the preponderance of comments are on the subject.

More linearity with active mode

The one aspect that seemed to suffer a twinge when moving from passive to active operation was coherence of the driver sets. Conversely, the resolution seemed to improve. Typically, when resolution increases, the drivers seem to meld better, but in this case, I sensed my ears being drawn more to the individual drivers than when run in passive mode. The change was not obnoxious, nor enough to quit active operation, but it took some adjustment. The finer detail, however, did not call for adjustment.

As systems I have built with the Whisper over the years have improved, I have paid attention especially to the bass performance, partly because when I first worked with the speaker, it really was shy on the low end for a big tower. As I have elevated the component chain and cables, the bass performance has improved, chiefly shown in more articulate reproduction of the bass line of both electric and upright bass. Much finer details of plucking and sliding of the fingers along the neck of instruments come through now. Electronic notes are heard to have character instead of sounding like a flat disgorgement of tone. Pieces of music that have overlaid LF effects and that used to sound like muddiness or distortion (I thought, maybe residing in the recording), are now revealed to be layered effects, even down below 25Hz! When the effort is made to tease out the subtleties of the low end, one realizes that composers and artists have not been neglecting the basement of the range!

The nature of the active setup reminded me of some cables that are recessed on the midrange and emphasize the treble. Do not misconstrue; I am not saying that the active performance was too tipped up, or strident. It was, however, slightly more emphasized in treble, and a touch less emphasized in midrange and mid-bass than the Salk SS 9.5. The SS 9.5 had to-die-for timbral qualities. When I switched speakers, there was some shift in this regard in the passive use, and another subtle shift in the same direction with active operation. In the first day or two of listening I was concerned it would prove too much for my taste and thought I would need to access the Wavelet’s software remote to adjust the relationship of the drivers slightly. But, as I gave it more time and played a wider selection of music with it, I decided it was acceptable at the current setting. I will add that I am not going to delve into the operation of the Wavelet’s software remote, accessible online through Bohmer Audio, because I gave it extensive treatment in previous articles regarding the Whisper speaker. This review focuses on the amps, and that is where the focus will stay.

There is one particular adjustment of the speaker that has proven effective over time in opening up the soundstage and getting the fullest experience from the speaker, whether in passive or active mode. It involves removing the rear grill that sits atop the rear firing driver and the backside of the bass drivers. If ever there was a demonstration that a grill has an immediate (usually negative) impact upon a speaker’s performance, this would be a fine example. I have taken to the habit of placing the box-shaped grills in the front corners of the room, making them quasi-tube traps. This maneuver both opens the speaker to allow nuances to fill from reflections off the front wall, making the speaker sound more like the quasi-open baffle that it is, and, simultaneously, improves the room-to-speaker interface in the bass region. When this is combined with my other adjustment that is always in play —shims under the back of the speaker’s apron to tilt the front baffle forward such that the woofers are more equidistant from my ears — I am assured of a more refined listening experience.

Don’t be shy of the active version of Legacy speakers now that ICEedge is here.

For many years I opted out of the fully active versions of Legacy speakers for one reason, that being I felt the ICEpower amps used internally were not of the caliber that I would lock them in as the amplification of preference long-term. Previous class D amps simply did not perform quite as well as finer class A and A/B, and I was unwilling to sacrifice amp selection for convenience and a slight performance benefit, knowing that it would be outdated in the near future.

I consider that decision validated, because the i.V4 Ultra shows how dramatically ICEpower has improved its own design. The performance level is now at a place where the buyer who is less concerned about longer term changes but wishes to start at a place closer to SOTA, does quite well opting for an active model of Legacy speaker. One would have to spend an inordinate sum relative to the price of the speakers to have a chance at a similar performance level. An attractive thought presents itself, the possibility that the i.V Ultra line will be enhanced as the years go by, and in that case, keeping the amps outside the speaker housing is a winning option. If you are going to take that route, make sure your cables are unassailable, and I can think of no better recommendation than the Iconoclast by Belden line. I still like having amps sitting apart from the speaker, even when in active x-over mode, because of options to change power cords, interconnects and speaker cables. Realistically, however, for the average audiophile who is not building dozens of systems, the amp nestled inside the speaker in the fully active version is a compelling choice.

As in the past, the results are not perfectly predictable

I returned to the passive x-over mode of the speaker and with some experimentation found . . . better sound! The significant change was swapping out the Exogal Comet for the COS D1 DAC + Preamplifier (reviewed), at the time of review a $10K integrated DAC. I have made many a beautiful system with this DAC, and it is a great foil to the Comet because it is innately warmer sounding without loss of resolution. If a new setup is syrupy, with too much warmth and not enough detail, I reach for the Comet, and if I have some taming to do, I put in the D1. With two DACs there is a solution for every speaker system. In my previous articles I pointed out that the superiority of passive or active x-over mode for the Whisper is dependent upon the particular equipment used. That proved correct once again as I found the COS D1 and the i.V4 Ultra amps in faux mono mode, one unit driving each speaker with one channel, to be the best result of the three.

In this higher MSRP passive setup the resolution was once again elevated, however, there was a significant drawback. Clearly, the macrodynamic envelope shrank, the bass recessed once again in line with the previous passive speaker system. The mysterious kinetic power to let the bass drivers crank it up with less effort had retreated. There was a touch less refinement in the low end, but it was a bit fuller. From the midrange through the treble the speaker was more distinct. The amp supported the speaker cables thus: one pair of Iconoclast TPSPC Speaker Cables with spades were sent to the midrange and treble, while bananas were put on the bass posts. The bass had its own amp, and the mid/treble were bi-wired, joined at another set of amp outputs, resulting in two channels providing three sets of speaker cables to the speakers (avoiding combining channels). I would have ideally used six channels of amplification for this system, however the limiting factor was the COS D1 having only one set of outputs for XLR or RCA. I used Audio Sensibility Y Cables to split the signal in order to gain a total of four channels, and consequently one channel of the i.V4 had to be bi-wired to drive two sets of inputs of the Whisper.

In the Iconoclast review I discuss experimenting with the banana and spade connections and conclude the spades are audibly superior. In the current setup with the Whisper, I loved the added presence in the midrange, but it was crowding out the bass; the bass seemed insufficiently powerful relative to the midrange. I compared a couple different combinations of spade and bi-wire, and ended up with an unexpected combo: one channel driving spades going to the bass posts and bananas going to the treble (bi-wired configuration), and the other channel driving single speaker cables with spade terminations going to the midrange posts. This is an unexpected outcome, but shows why the audiophile needs to try all combinations and not assume the outcome is foregone. It took a fair bit to find the superior performance of this combo in passive x-over mode, but it was found! My conclusion, then, in regard to use of the Wavelet has not changed over the years. It is a fine all-in-one unit that may outperform any given integrated DAC or DAC and preamp combo, but I did not find it to dominate all combinations of gear. One would likely have to search and spend perhaps double the money to better it, but it can be done if desired. I think it would typically require higher end components, such as the COS D1 DAC, to get it done. Also, keep in mind that the room correction processing native to the Wavelet would be lost.

However, this is not a review of the Wavelet, but of the i.V4 Ultra. No discouraging words come to me in regard to its use in any of these combos. I heartily recommend it for either operation, passive or active. I can see why Legacy wants customers of its speakers to pair them with the i.V and i.V Ultra series of amps. It is a tough combination to beat, especially at the price.

A sea of beautiful sound

I consider the 2020-2021 transition to be one of the most pivotal times in my 30+ years of being an audiophile, and the emergence of dominant class D amplification is a large contributor. The i.V Ultra amplifier has handily outdone all other amps reviewed, regardless of genre, which is unprecedented. I invite the community to peruse the entire listing of amps I have reviewed from the past 14 years; there is not a one of them, not a single one, that I would prefer to be hearing. It’s not just a matter of being somewhat better, or in some respects having advantage, but rather a wholesale superior experience.

Not everyone will reach the same conclusions, and I expect there to be significant push back from a particular group in audiophilia, those who avoid definition in favor of coloration. The i.V Ultra dispenses with indistinct overtones, but many listeners adore a dark or syrupy coloration, just as some enjoy the box contribution of a speaker’s cabinet. Nothing will change that, and preferences will continue to push people toward particular genres of products. But, overall, the bulk of the community will rapidly see the advantages of the new class D products, and in particular the i.V Ultra Amplifier.

There is a convergence of the finest attributes of sound quality happening in class D amps right now! Class D, which was said for decades to hold promise, is now delivering on that promise. Increasingly, audiophiles will expect the best of characteristics in sound quality in one genre, class D. As more class D amps flood showrooms and catalogues, the question will be not which genre of amp to get, but which class D amp to own.

This review has become a headlong rush to see what speakers will be paired next with the i.V4 Ultra because its power, immediacy with delicacy, rich layering, and fullness in timbre beg to be showcased with a lot of transducers. Its love potion of performance gets in the veins and is impossible to forget. One unit is enough to make me salivate at the thought of how it will sound in future rigs. Two units, either in active mode with the Whispers, or in the faux monoblock configuration with passive speakers, makes me wonder what fun I will have next with them? What kind of fun might you get into with the i.V (especially the Ultra) series of amps from Legacy Audio?

Copy editor: Dan Rubin

ASSOCIATED COMPONENTS:

Source: Small Green Computer sonicTransporter AP I7 4T and SONORE Signature Rendu SE and systemOptique

Streaming Music Service: Tidal premium

DAC:  COS D1 DAC + Pre; Exogal Comet DAC and Plus upgrade power supply and Pulsar IR receiver; Eastern Electric Minimax DSD DAC Supreme with Burson, Sonic Imagery and Sparkos Labs Discrete Opamps

Preamp: TEO Audio Liquid Preamplifier

Amps:  Pass Labs XA200.8 Mono Blocks; Exogal Ion (PowerDAC, used exclusively with Exogal Comet DAC); Legacy Audio i.V4 Ultra (pair, totaling 8 channels)

Integrated: Redgum Audio Articulata; Kinki Studio EX-M1+

Speakers:  Aspen Acoustics Lagrange L5 MkII; Salk Sound SS 9.5 custom; Kings Audio Kingsound King III; Legacy Audio DSW Clarity Edition; PureAudioProject Trio15 Horn 1; Pure Audio Project Quintet15 Horn1; Kings Audio King Tower omnidirectional; Ohm Walsh Model F (restored)

Subwoofers: Legacy Audio XTREME HD (2)

IC’s: Iconoclast 4×4 “Generation 2” XLR and 1×4 “Generation 2 RCA”; Clarity Cable RCA with Audio Sensibility Y Cables; Schroeder Method Audio Sensibility RCA; Schroeder Method Clarity Cable XLR with Audio Sensibility Y Cables; TEO Liquid Splash-Rs and Splash-Rc; TEO Liquid Standard MkII; Clarity Cable Organic RCA/XLR; Snake River Audio Signature Series Interconnects; (Schroeder Method, self-assembled with Audio Sensibility Y Cables used with several brands)

Speaker Cables: Iconoclast by Belden SPTPC Level 2 Speaker Cables; TEO Cable Standard Speaker; Clarity Cable Organic Speaker; Snake River Audio Signature Series Speaker Cables;

Digital Cables: Clarity Cable Organic Digital; Snake River Audio Boomslang; Silent Source “The Music Reference”

USB: Clarity Cable Supernatural 1m

Power Cables: Belden BAV (Belden Audio/Video) Power Cord; Clarity Cable Vortex; MIT Oracle ZIII; Snake River Audio Signature Series; Anticables Level 3 Reference Series

Power Conditioning: Wireworld Matrix Power Cord Extender; Tice Audio Solo

Manufacturer’s Comment (added 5/21/2021):

Dear Editor,

It is with humility that I thank you for your extensive review.  It reads as a formal declaration that Class D amplification has arrived and it brings some significant benefits.  The standards set by the likes of James Bongiorno and  Nelson Pass who brought transistors to acceptance, or the elegant refinements of a Classic tube design from Kevin Hayes are not to be overshadowed. Instead they must be recognized as lasting steps in the progress of amplification for musical enjoyment.

Our vision with the i·V design was from a loudspeaker control perspective. Build a practical amplifier that would provide more voltage with the sustained current to back it up. Make it quiet, durable and as neutral as possible.  The dynamic of today’s 24bit recordings demand a lower noise floor on playback as well as more power for transients.

https://legacyaudio.com/news/is-your-system-24-bit-ready

Legacy continues to offer service and stock parts on all of our products since day 1 of our 38 year history. This includes our latest i·V amplifier line. My longtime friend and industry colleague, Doug Dale of Coda, (who began with Nelson Pass in the days of Threshold) fabricated the early Legacy amplifiers for us continues to service these vintage units and offers upgrades.

Bill Dudleston
Chief Designer, Legacy Audio