Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click here.

In the last few years I have reviewed the two integrated amplifiers currently on offer from Lyngdorf Audio: the TDAI-3400 and TDAI-1120. I have always admired Lyngdorf’s integrated amplifiers for their fantastic sound and excellent user interface, and these two amps were no exception: they performed wonderfully in my system. I was especially impressed by the room-correction system built into these amps, Lyngdorf’s proprietary RoomPerfect software.

The 3400 and 1120 are both digital amplifiers that do away with digital-to-analog conversion and preamplification—and the noise and distortion attendant to these stages—sending the digital signal directly to their respective power-amp section. This earned the TDAI-1120 a SoundStage! Network Product of the Year Award in 2021 for Innovation in Design.

The two TDAI models are based on Lyngdorf’s class-D amplifier topology, Equibit, as is the SDA‑2400, a stereo power amplifier. The MXA-8400, Lyngdorf’s first multichannel power amplifier, is the only model in the company’s line of amplifiers that does not use Equibit. Instead, it uses Purifi Audio’s Eigentakt amplifier technology. This shouldn’t come as a surprise: Peter Lyngdorf, founder of Lyngdorf Audio, cofounded Purifi, and the two companies share several key figures and designers. At $8999 (all prices in USD), the eight-channel MXA-8400 is not cheap, but considering the cost of Lyngdorf’s surround processors and multichannel amps of similar caliber from competing brands, its price is not unreasonable.

Given the exceptional design and build quality of the MXA-8400 and of other Lyngdorf products, the company’s two-year warranty is surprisingly short.

Bridged multichannel—stereo on steroids

Before the introduction of the MXA-8400, the two-channel SDA-2400 was the only amplifier Lyngdorf offered that could be used with its surround processors. Multiple units could be pressed into service for multichannel use. But the SDA-2400 is a curious creature in Lyngdorf’s amplifier line as no stereo preamplifier has been available for it. It could be used, however, with the TDAI-3400 integrated amplifier in a bi-amplified configuration.

The MXA-8400 will serve Lyngdorf’s surround processors more aptly, but it should be equally at home in a high-quality two-channel system thanks to its fantastic Eigentakt amplification modules. Each adjacent pair of the MXA-8400’s eight channels can be set to a two-channel mode, where each channel is independent, or to a bridged mode, where the two channels are linked. In two-channel mode, power output is rated at 200Wpc into 8 ohms, 400Wpc into 4 ohms; in bridged mode, output is rated at 800Wpc into 8 ohms (power rating into 4 ohms is unspecified).

Power in and power out

The MXA-8400 is powered by Lyngdorf’s PowerPerfect power supply, which is capable of delivering 3.2kW of output power across the eight channels, and even more when peak output is called for. PowerPerfect is said to be extremely efficient, meeting high-power demands with exceptional noise filtering. It prevents AC noise from affecting the signal and doesn’t generate noise that could affect other components. Lyngdorf claims that by optimizing the amp’s power supply, it was able to achieve measurable improvements in its performance.

We have discussed Purifi’s Eigentakt class-D amplifier modules at length in the past in reviews of NAD amplifiers that use them. In September 2020 Doug Schneider devoted an editorial feature to one. And so I won’t delve into the technical details here. It’s important to note, though, that measurements of these amplifiers by Diego Estan, in the SoundStage! Audio-Electronics Lab, revealed not only high power output but also ultra-low distortion and flat frequency response into varying speaker impedances—qualities not all class-D amplifiers are known for.

Lyngdorf assembles the Eigentakt power modules for the MXA-8400 in-house, under license from Purifi, to ensure they conform to its own manufacturing standards. The power modules underlying the MXA-8400’s eight channels are all built onto a single long circuit board. This obviates the need for connecting wires, allows for thicker copper traces, and places key components farther apart, which reduces noise and distortion. Lyngdorf has been able thereby to optimize the circuit design while staying within Purifi’s specifications.

Lyngdorf claims the MXA-8400 has a frequency response of ±0.1dB (20Hz–20kHz), THD of 0.001% at full power from 20Hz to 20kHz into both 8 and 4 ohms, and THD of 0.0006% and 0.0007% at 10W into 4 ohms from 20Hz to 20kHz in low- and high-sensitivity modes, respectively. The maximum output voltage per channel is specified as 58V peak in two-channel mode and 116V peak in bridged mode. I look forward to seeing Diego’s measurements of this amplifier, but I have little doubt that the MXA-8400 will meet or exceed Lyngdorf’s performance claims.

Physical interface

The exterior of the MXA-8400, with its simple, straight lines and matte-black finish, is quite understated. It measures 5.7″H × 17.7″W × 13.7″D and weighs only 22 pounds. A dark inset horizontal strip bisects the thick front panel, giving the amplifier the appearance of a stacked pair of SDA-2400s. Presented in small white lettering is the Lyngdorf logo, on the lower left, and the model designator, on the lower right. A bluish-white LED power indicator is set next to the logo. It blinks slowly for standby mode, glows steadily when powered on, and blinks rapidly to indicate a fault.

The back panel bristles with the inputs and outputs for the amp’s eight channels but is still tidy. Most notable are the eight Neutrik speakON speaker connectors. Lyngdorf includes eight speakON connectors so that owners can terminate their own speaker cables to fit the jacks—few cable manufacturers provide speakON termination as an option. Alternatively, adapters can be used. The speakON-to-banana adapters I received from Lyngdorf spared me the trouble of re-terminating all of my cables for the 5.2 setup. For the stereo setup I re-terminated a couple of 12-gauge Analysis Plus Blue Oval speaker cables with speakON connectors. A 12-gauge cable fits well in the connectors; a larger gauge cable might not. (It should be noted that the speaker-cable wire conductors must be connected to different clamps within the speakON connector in bridged and two-channel modes.) The cables were a cinch to connect and disconnect with the speakONs. The connectors produced a reassuring click when locking into place, and the connection was solid.

The MXA-8400 has only XLR jacks for its inputs, each jack set directly below the corresponding speakON jack. A small slide switch next to each of the four pairs of adjacent channels is used to bridge the corresponding channels. Another small switch labeled Power State assigns control of power switching to either an external trigger signal or to an incoming audio signal. (The unit powers down if an input signal is not sensed for 15 minutes.)

Also seen on the back panel are a mains power rocker switch, next to an IEC power inlet, 3.5mm trigger-in and trigger-out jacks, an ethernet port for servicing, and a sensitivity switch to better match the output voltage of the preamplifier in use. The Low setting is meant for an input voltage of approximately 6V; the High setting for a voltage of approximately 2V.

Stereo and multichannel setups

As mentioned, the MXA-8400 served primarily as a stereo amplifier in my system, replacing a pair of Anthem M1 monoblocks. I took advantage of its bridged mode to provide more power to my MartinLogan Masterpiece ESL9 loudspeakers. My Anthem STR was the preamplifier, as usual. I did engage the STR’s built-in ARC Genesis room-correction system from time to time but not its bass-management system. I did not use a subwoofer when listening to the MXA-8400 in stereo.

An Intel NUC MiniPC, linked by an AudioQuest Carbon USB interconnect, served as my main source, streaming Tidal via Roon as well as locally stored digital files. The rest of the system, apart from the re-terminated Blue Oval speaker cables, comprised my usual assortment of accessories: an AudioQuest Jitterbug jitter reducer; additional cables from Shunyata Research, Analysis Plus, Nordost, and Clarus; and power products from ESP, Zero Surge, and Blue Circle Audio.

To audition the MXA-8400 as a multichannel amplifier, I connected it to an Anthem AVM 60 surround processor. To the ESL 9s I added a MartinLogan ElectroMotion ESL C center speaker, a pair of Definitive Technology BP9080x floorstanders as surround speakers, and two JL Audio E-Sub e112 powered subwoofers—a most competent 5.2-channel system.

Stereo sound

In the stereo setup, in two-channel mode, the MXA-8400 proved to be an accomplished amplifier with ample power and an extremely neutral character. Even during casual listening, as I let the amp settle into my system, I could not but notice how controlled, effortless, and musical its sound was. Listening to the new SACD version of On Every Street (DSD64 DSF, ripped from Mobile Fidelity Sound Lab UDSACD 2239), from Dire Straits, for instance, I enjoyed a pleasant sense of ease as the melodic “Calling Elvis” flowed smoothly from the speakers.

Nothing I threw at the MXA-8400 would trip it up. From classic orchestral recordings to the latest EDM remixes, everything sounded just about perfect. I could not detect any noise or distortion, nor could I perceive any sonic character I could attribute to the amplifier itself. This didn’t surprise me: my impression of the fabulous NAD Masters M23 and M28 power amplifiers, which also employ Purifi Eigentakt technology, was similar. Indeed, in 2023 I declared the NAD M23 one of the very best amplifiers, and it received our Product of the Year Award for Exceptional Value. The Lyngdorf MXA-8400 is at least its equal in performance and deserving of at least as much praise.

Having auditioned the MXA-8400 in two-channel mode for a few weeks and having found its performance most satisfactory, I then switched to bridged mode to see what improvement could be attained on its already stellar sound.

Continuing with some more fun, nostalgic music from the 1980s and ’90s, I cued up the SHM SACD version of Asia’s eponymous album (DSD64 DSF, ripped from Geffen Records UIGY-9041) and cranked up “Heat of the Moment,” the opening track. This impeccable 1981 Mike Stone–production has that precise, bracing sound characteristic so typical of albums of that time. And like many of those albums, it too is somewhat bass shy. The Lyngdorf amp reproduced this track flawlessly, giving it a sweeping, thrilling quality, its superclean sound unraveling the subtlest complexities in this high-quality recording.

As thrilled as I was with the MXA-8400’s presentation of this track, I was even more thrilled with its presentation of the next, “Only Time Will Tell.” In bridged mode, the MXA-8400 still had an open, inviting sound, but now every sonic nuance stood in sharp relief. The synth horns that open the song were immensely expansive, giving the vast soundstage a distant, echoey quality. And while those synth chords seemed to expand with no limit, the hi-hat was rigidly planted just to the inside of the right speaker. John Wetton’s voice had a subtle, slightly diffuse, other-worldly character, which was contrasted by the bold and soaring guitar riffs that highlight this quintessential power ballad.

I love Van Cliburn’s 1958 performance of Tchaikovsky’s Piano Concerto No. 1 (DSD64 DSF, ripped from BMG Music 82876-61392-2), with Kirill Kondrashin conducting the RCA Symphony Orchestra. Compared to some of my more recent classical favorites, I’ve found the imaging of the orchestra in this recording to be slightly flat—two-dimensional. But the MXA-8400’s powerful presentation, particularly in the final movement, had such immediacy and texture that it brought this album to life.

When I listened to Madonna’s Immaculate Collection (16/44.1 FLAC, ripped from Sire 7599-26440-2), a compilation CD mixed in QSound, the wraparound, three-dimensional effect in this track was especially pronounced. No other amplifier in my system has been able to reproduce the mix’s subtle timing, frequency, and amplitude cues as perfectly—to image instruments and vocals as distinctly.

Multichannel sound

To test the multichannel performance of the MXA-8400, I unbridged its four pairs of channels and connected it to the five speakers of my setup. Recordings that made full use of multiple channels, not just for background ambience, sounded incredibly coherent with the transparent and balanced power of this amp.

The voices of Boyz II Men on their cover of the Beatles’ “Yesterday,” from their DTS CD II (5.1 DTS FLAC, ripped from DTS Entertainment 71021-51001-2-8), jumped out at me with stunning fidelity—from the front speakers, center-channel speaker, and full-range surrounds. The baritone of Nathan Morris on this track was heard mostly from the center speaker. In some setups, it can become congested and not integrate smoothly with the other channels; with the Lyngdorf amp and Martin Logan center speaker, Morris’s deep vocals blended seamlessly with the many voices from the other channels.

The powerful, bluesy voice of Yazoo’s Alison Moyet, from the duo’s 2008 box set In Your Room (5.1 DTS DVD-V, Mute 5099921516825), is embodied mostly in a phantom center image on the DTS mixes that are included with the DVD, but there is still plenty going on in the surround channels. Again, the Lyngdorf sounded amazingly lucid and coherent. On “Anyone,” the percussion was spread holographically through the channels with sparkling clarity. On “Nobody’s Diary,” the backing vocals, in the surrounds, were perfectly matched tonally with the vocals in the mains.

Comparisons

It’s difficult to overstate the power, control, and thrills that the MXA-8400 brought to my system, especially in bridged mode. No other amplifier I’ve ever had in this system provided the same level of enjoyment. The control and authority in the bass was still there when I switched back to my Anthem M1 monoblocks ($3999 each), but the midrange and upper frequencies were not as clean. This resulted in some loss in image sharpness and soundstage depth.

When I played “Heat of the Moment” with the Anthems, the sound was similarly clean and expansive, but on “Only Time Will Tell” the vocals did not sound quite as palpable, and the prominent hi-hat was not imaged as distinctly. I heard this difference in presentation again when I listened to “Full of Life,” from Paranoïa, Angels, True Love (24-bit/176.4 kHz FLAC, Because Music / Tidal), by Christine and the Queens. The haunting vocals and gently rising and falling strings were exceptionally clean and clear with both amps, but the Lyngdorf carved out Héloïse Létissier’s voice in slightly more precise outlines and imparted more weight and body to it. And when the bass really kicked in, not only was the Lyngdorf able to keep up with the Anthems, despite their higher rated output (1kW), it went a little deeper and seemed a little tighter.

Near the end of the review period, I took delivery of two sample units of the NAD Masters M23 power amplifier ($3749) for a forthcoming review that will also include the new M66 preamplifier. I didn’t have much time to compare the Lyngdorf to the NAD amplifiers—I had to send the Lyngdorf to Ottawa for measurements and photography—but I did find, after a few days of burn-in, that the NADs had a touch less weight in the bass, a bit less sparkle in the highs. With the Lyngdorf and NADs bridged, the deep bass tones on “Full of Life” were more defined and authoritative with the Lyngdorf, and the towering synth and piercing guitar riffs on “Only Time Will Tell” had a more crystalline quality. The differences between these two superlative amps were small, but they were most certainly noticeable.

Whether it was in bridged or two-channel mode, and whether or not the ARC Genesis room correction was engaged on the Anthem STR preamplifier, the Lyngdorf MXA-8400 continually impressed me with its exemplary combination of power, transparency, and musicality. In bridged mode, its dynamics and ability to exert control over the woofers of my ML ESL 9s was so absolute that I never missed the dual JL Audio E-Sub e112 subwoofers that are usually part of the system.

Conclusion

Some prospective buyers may balk at the hefty price of the MXA-8400. But comparable multichannel amplifiers from Bryston, Hegel, McIntosh, and others cost just as much or more. A pair of bridgeable M23 amplifiers would cost a little less and provide similar power; lower-price NAD amplifiers that are based on Eigentakt technology are also available, although they would be no match for the Lyngdorf. And of course, those who listen mostly to stereo recordings may deem the use of an eight-channel amplifier for stereo overkill, even if it allows bridging for additional power. Still, the MXA-8400 promises a rich, full multichannel experience should it be sought and a truly exceptional stereo sound, especially in bridged mode.

. . . Roger Kanno
rogerk@soundstagenetwork.com

Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click here.

Associated Equipment

• Speakers: Martin Logan Masterpiece Classic ESL 9, ElectroMotion ESL C (center channel), Definitive Technology BP9080x (surrounds).
• Subwoofers: JL Audio E-Sub e112 (x2).
• Preamplifiers: Anthem STR (stereo), AVM60 (surround).
• Power amplifiers: Anthem M1 (x2 monoblocks), NAD Masters M23 (x2 in BRIDGE MODE), SensaSound TPO-7300.
• Digital sources: Intel NUC computer running Windows 10, Roon, and Tidal; AudioQuest JitterBug jitter reducer, Oppo Digital UDP-205 4K Ultra HD universal Blu-ray player.
• Turntable: Pro-Ject Audio Systems X1 turntable with Pick it S2 cartridge.
• Speaker cables: Analysis Plus Blue Oval, Shunyata Research Venom-X.
• XLR interconnects: Shunyata Research Venom-X, Nordost Quattro Fil, Analysis Plus Silver Apex.
• USB link: AudioQuest Carbon.
• Power cords: Clarus Cable Aqua, Essential Sound Products MusicCord-Pro ES.
• Power conditioners: Blue Circle Audio PLC Thingee FX-2 with X0e low-frequency filter module, Zero Surge 1MOD15WI.

Lyngdorf Audio MXA-8400 Multichannel Amplifier
Price: $8999.
Warranty: Two years, parts and labor.

Steinway Lyngdorf
Rævevej 3
7800 Skive
Denmark
Phone: +45 9614-5600

Email: contact@lyngdorf.com
Website: www.lyngdorf.com