Earlier this year, I had the pleasure of reviewing Chord Electronics’ new Ultima Pre 3 preamplifier. Along with the Ultima preamp, Chord shipped me the subject of this review: the matching Ultima 6 power amplifier ($9925, all prices in USD). My first encounter with these components was in February this year at the Bristol Hi-Fi Show. I was impressed enough with what I heard to request review samples.
Like the Ultima Pre 3, the Ultima 6 doesn’t just feature a rehash of existing Chord circuits. It’s a ground-up redevelopment, incorporating redesigned power supplies, output transistors, and circuit layout, encapsulated in a stunning aircraft-grade aluminum chassis.
Rated at 180Wpc into 8 ohms and measuring 7″H × 17″W × 19″D, this 49-pound behemoth uses the same design language as the Ultima Pre 3, with the same oversized, glowing power button on the front panel and internal-circuit lighting. The Integra leg supports, rear-mounted heat sinks, and 28mm-thick front panel are hewn from solid aluminum. It’s an imposing beast, so large it wouldn’t fit in my rack. Fortunately, I had an old Sound Organisation two-tier turntable support to hand and the big British amp sat perfectly on the top plate. The Ultima 6 has the kind of build quality one normally associates with bank vaults!
On the rear panel are a pair of unbalanced RCA inputs and a pair of balanced XLR inputs. I used both during the course of this review. The speaker connections are high-quality, gold-plated terminals for a single pair of loudspeakers. There’s also a 12V trigger input. The mains socket is a 16A C-19 type that requires the supplied heavy-duty mains cable rather than the more commonplace IEC lead.
The Ultima 6 is a class-AB design that operates in class A at low levels. Chord Electronics’ preamps and power amplifiers use bespoke switched-mode power supplies. Switched-mode power supplies generally sound inferior to linear power supplies, and have a bad rap for polluting the mains power feed. But in the Ultima 6, a sophisticated mains input filter shields the amplifier from disturbed mains input, and also ensures that the mains itself is untouched by emissions from the onboard switched-mode power supply.
Chord Electronics is keen to point out that its new dual-feed-forward topology is the company’s first all-new circuit design in three decades. What it does is monitor and then error-correct the signal before the output stage in order to increase accuracy. The Ultima 6 uses 16 proprietary MOSFET power devices fed by highly advanced and refined drive circuitry featuring an ultra-low-distortion, high-voltage amplifier operating at very high speed.
The proprietary TO3-style, dual-die, lateral-matched MOSFETs are complemented by fully balanced input circuitry with DC-tracking servos and full temperature compensation. Due to its class-A circuitry, the Ultima 6 runs warm even at idle even at idle and can draw up to 1500W of peak mains power when running hard—hence the chunky power cable. In short, Chord’s switched-mode supplies are extremely sophisticated—a world away from those found in cheap domestic appliances.
Whereas most power amplifiers employ high-powered bipolar transistors, Chord Electronics worked with a UK semiconductor manufacturer with roots in the aviation industry to develop its own range of metal-on-silicon transistors. As the company notes, most power transistors are designed to switch on and off quickly, and perform at their worst when between these states—which is where they spend most of their operating life when amplifying music. Normally, a bias current is applied to keep them switched on and feedback is applied to lower distortion. In contrast, the 16 proprietary power transistors in the Ultima 6 are designed for audio, not switching—in other words, they are optimized for amplifying music. This bespoke design also has the benefit of enabling more accurate thermal matching of devices and so avoids the need for temperature-balancing resistors in the output stages.
For my listening tests, I removed my Naim Audio NAP 250 power amplifier from my system and substituted the Ultima 6, connecting it to my Naim NAC 82 preamplifier and HiCap power supply, reasoning that this would enable me to assess the performance of the Ultima 6 in the context of my own system. In later listening sessions, I substituted the Ultima Pre 3 for my Naim preamp.
Sources included my Michel GyroDec turntable with SME IV tonearm and Audio-Technica AT-OC9 cartridge, Naim CDI CD player, and Naim NDX streamer. Completing the test setup was my reference pair of ATC SCM40 three-way loudspeakers. The SCM40 is an incredibly neutral and revealing loudspeaker with full-range bandwidth and tremendous speed and slam. It soon highlights deficiencies in partnering equipment, so it’s a perfect reviewing tool. With its enormously heavy drive units, it loves power, and by modern standards is not particularly efficient. In short, a pair of ATC SCM40s thrives on amplifiers capable of delivering high current and more than 75Wpc—an ideal match for the Chord bruiser!
Wanting to hear what the Ultima components were capable of, I was keen not to skimp on cable. A brief call ensured I was supplied with exotic balanced XLR cables from the Chord Company, an entirely unrelated firm with a similar name. Valued at $6800, the 2m (6.5′) Sarum T Super ARAY cables allowed the amplifiers to be run fully balanced from end to end. To connect my Naim preamp to the Ultima 6, I was furnished with some impressive Chord Co. SignatureX ARAY cables ($1500) featuring XLR-to-RCA terminations. Before the new cables arrived, I used various amplifier combinations with my own more modestly priced Chord Co. and QED cables to get the amplifiers warmed up and to establish some initial impressions.
Chord Company Sarum T Super ARAY balanced connections and Naim NAC A5
What followed was something of a revelation! When I switched over from my own basic cables and plugged in the Chord Company ARAY interconnects, I was struck by an incredible change in dynamics, a lowering of noise floor, and a more attention-grabbing performance from the system. This came as a big surprise, as I have previously been somewhat cynical about elite cabling. Show me a $15,000 SME turntable and I can see where the money has gone, but it’s always seemed to me that beyond a certain point, a wire is a wire. I’m eating humble pie now, and coming around to the view that Chord Co. is on to something when it cites the increased level of electrical and electronic interference in our homes as a cause of degraded sound. Chord Co.’s focus on screening, geometry, and RF rejection does seem to have significant sonic benefits. These cables are good; in fact, not just good but outstanding . . . Good enough that I actually contacted Chord Company’s PR department to request a factory visit to learn more about the company’s technology. Look for the report on that factory visit on SoundStage! Global, later this year.
As regular readers know, I have a passion for Scottish bands. This may be surprising for an Englishman born and raised near Liverpool—which, as everyone knows, is the center of the musical universe! Ignoring my Scouse heritage yet again, I fired up Del Amitri’s “In the Meantime” from a two-disc, special-edition release of the band’s superb fourth album, Twisted (CD, A&M 540 396-2). I was immediately struck by the amount of power the Ultima 6 was delivering at just 9 o’clock on the NAC 82 preamp’s volume control—it made me think that the Ultima 6 could drive any loudspeakers to ridiculous levels. Allied to that power was a sense of absolute control over the music. Justin Currie’s Scottish brogue cut through on the opening vocal lines with admirable transparency, and the rich timbre of his voice was beautifully rendered. Meanwhile, the accompanying organ sounded rich and fulsome, as well as clean and detailed.
Built like a bank vault but with better acoustics
One of my recent musical discoveries has been the British country trio Remember Monday. Streaming their single “Home to Me” (16-bit/44.1kHz FLAC, Remember Monday / Tidal), I was struck by the way the Chord power amplifier reproduced the beautiful harmonies on this song, yet clearly differentiated each individual voice. It was a sure sign that this amplifier wasn’t muddying the sound or losing transparency, but rather conveying the musical intent. There was something utterly captivating about the blending of these three beautiful female voices—this is a band that really knows how to craft a melody and convey emotion. The acoustic guitars were extremely articulate and had a genuine sense of presence in the room as I listened. In addition, the system had enviable timing, so that the way notes were shaped and played, and the subtle interplay of attack, sustain, and decay were rendered with great precision. Listening to this track through the Ultima 6 made me even more grateful that I am going to see the band live later this year in London!
If you want to know just how well this trio can craft a song, check out their single “Let Down” (16/44.1 FLAC, Remember Monday / Tidal). You’ll immediately realize that this is a band that can rock with the best. They’re tight enough to impress, but loose enough to rock. The interplay of the whooping chorus, guitars, and powerful drums had me wanting to punch the air—ideally, driving into the sunset in a convertible Mustang with the three of them singing to me from the passenger seats!
One of the most important elements of quality hi-fi is the ability to reproduce the energy and emotion of an artist’s performance. On such a system, you can really tell when the musicians are totally into it and are having a ball. At the end of this track, a band member says “Smashed it,” and the rest laugh. She’s bang on. I heard exuberance and genius in equal measure from the band and the system.
Remember Monday—sublime harmonies and ready to rock
Another aspect of the Ultima 6 that consistently impressed me was its incredibly low noise level. In a recording of Dmitri Shostakovich’s Piano Concerto No. 2 by Dmitri Alexeev and the English Chamber Orchestra conducted by Jerzy Maksymiuk (16/44.1 FLAC, Warner Classics / Tidal), I heard absolutely no hum or hiss. Alexeev’s incredibly delicate playing in the second movement had particularly black silences between the notes, which conveyed the expressiveness of the playing and the raw emotion of the piece. There was a consistent feeling of control. The Ultima 6 was neither adding to nor subtracting from the music, merely amplifying it.
As I began to get the measure of the Chord Ultima 6 power amplifier, one question remained: How fast could it react to sudden, transient signals? To test this, I selected Electric Guest’s “Awake” from the band’s 2012 debut studio album, Mondo (16/44.1 FLAC, Downtown Records / Tidal): a slice of perfect pop electronica. Fronted by the NAC 82, the Ultima 6 did a great job, reacting to the drums, keyboards, and handclap sounds with metronomic precision.
For my next round of listening, I replaced my Naim NAC 82 preamp with the Chord Ultima Pre 3. There’s a lot of great contemporary music around today, so I cued up the title track of LP’s magnificent album Lost on You (16/44.1 FLAC, Vagrant Records / Tidal). The all-Chord combination rendered the pounding drum backing with jaw-dropping depth and slam, but the top end of the acoustic guitar and Laura Pergolizzi’s vocals were perhaps a shade less incisive than I’m used to hearing.
My venerable Naim NAP 250 (bottom) goes head-to-head with the Chord Ultima 6
For sheer exuberance, you can’t beat the title track of Jimmy Smith’s The Cat (16/44.1 FLAC, Verve Records / Tidal). The musicianship on this big-band recording is outstanding. Smith fires runs of notes out of his Hammond B-3 like bullets from a Gatling gun while the rest of the band is on fire—especially drummer Grady Tate. Played through the Ultima Pre 3 and Ultima 6, Tate’s thrilling drum fills felt extremely solid, causing the air to physically jump in the room when I played the track at higher levels. Bass lines were deep, underpinning the track with a firm foundation upon which the other elements of the mix are built. The lead trumpet melody line had tremendous presence through the Chord combo, and it was easy to hear what each instrumental element of this very busy recording was contributing to the proceedings. The soundstage extended in a broad swath beyond the confines of the loudspeakers, and there was a sense of great clarity and control.
Comparing the sound of the Chord and Naim power amplifiers revealed some differences in their sonic personalities. Where the Ultima 6 differed from the NAP 250 was in dynamics, with the Naim being a little more dramatic on musical climaxes and having a little more attack and snap. With the Naim, I was acutely aware of the moments when a performer is right on the edge of their musical or technical range. With the Chord’s more refined delivery, this was not quite so apparent.
Fronted by the Ultima Pre 3, the Ultima 6 amplifier delivered more slam and depth on the drums on LP’s “Lost on You” than the Naim, but vocals and guitars were less incisive. Overall, the sound of the Chord amplification was cleaner, which is high praise coming from someone who has exclusively used Naim for over 30 years.
On the Jimmy Smith recording, the all-Chord combination sounded cleaner and more controlled than the Naim, but was less dynamic, and ultimately less exciting. The Naim amplifier had a slightly more aggressive edge and greater verve, which really captured the way that the players are walking on a knife edge. Sure, the Naim was a little ragged at times, but it certainly made for a tremendously exciting listen.
Chord’s delightful internal lighting showcases the circuit design
On the Shostakovich concerto, the silences between Alexeev’s delicate piano notes were even blacker on the Chord amplifier than on the Naim, which is no slouch in this respect. The Chord power amplifier quite simply had a vanishingly low noise floor, and that enabled the inner nuances of this startlingly beautiful piece to be revealed. Spotlighting low-level ambient cues, showcasing subtle instrumentation, and demonstrating the timbre and quality of the magnificent piano that Alexeev is playing were real strengths of the Ultima 6.
This is a grandly emotional composition; in fact, one of the most sublimely moving pieces of piano music ever written. The Ultima 6 demonstrated the glorious richness of the accompanying strings that complement the piano’s melody in this superb recording. The interplay between these two elements and the expressiveness of the pianist in the second movement combine to convey the enormous emotional resonance of this brilliant concerto. Listening through the Ultima 6, I was moved to tears by the impact of its portrayal. No Chord Electronics amplification has done that to me before—ever.
What we have here is a beautifully engineered amplifier that is extremely powerful, capable of driving a wide range of loudspeakers with ease. Sonically, the Ultima 6 represents a significant advance over any Chord power amplifier I have heard to date, because it captures the emotional essence of music far better than Chord Electronics’ previous designs.
In terms of detail retrieval, transparency, bandwidth, soundstage, and stability, the Ultima 6 is up there with power amplifiers at the top of its price class. I absolutely loved it, especially when driven by my Naim NAC 82 preamp, which added a little more exuberance to the sound. Partnered with the matching Ultima Pre 3, the combination was also deeply impressive, and offered a superb insight into the music. This combination was particularly notable for the way it handled low-level detail, such as ambient cues, the sound of fingers on guitar, or the subtle inflections in the vocal performance of an artist. The sound was never fatiguing, and always absolutely natural. It’s easy to see why the BBC uses Chord amplification.
This new lineup from Chord Electronics is very strong, and the Ultima 6 power amplifier comes highly recommended. It’s one of the very best power amplifiers you can buy without venturing into ludicrous uber-fi territory. The Chord Electronics Ultima 6 is incredibly neutral, is as rugged as Stonehenge, and looks way cooler than 99% of audio gear out there. Now you’ll have to excuse me while I daydream about renting that Mustang convertible and taking the Remember Mondays for a drive . . .
. . . Jonathan Gorse
- Analog Sources: Michell GyroDec turntable, SME Series IV tonearm, Audio-Technica AT-OC9 MLII cartridge, Trichord Research Dino Mk 3 phono stage with Never Connected Dino+ power supply, PS Audio Stellar phono stage.
- Digital sources: Naim CDI CD player, Naim NDX streamer.
- Preamplifiers: Naim Audio NAC 82, Chord Electronics Ultima Pre 3.
- Power amplifier: Naim Audio NAP 250.
- Power supply: Naim Audio HiCap.
- Loudspeakers: ATC SCM40.
- Cabling: Chord Company Sarum T loudspeaker cables, Naim NAC A5 loudspeaker cables, Naim interconnects on all Naim amplification, Chord Co. Sarum T Super ARAY XLR, Chord Co. SignatureX Tuned ARAY DIN-RCA, Chord Co. SignatureX RCA-XLR, Chord Co. EpicX ARAY RCA. Chord Co. Chameleon interconnects for phono stages, QED interconnects for secondary sources.
Chord Electronics Ultima 6 Power Preamplifier
Warranty: Five years, parts and labor.
Chord Electronics Ltd.
Maidstone ME16 9NB
Phone: +44 1622 721444
The Sound Organisation
1009 Oakmead Drive
Arlington, Texas 76011
Phone: +1 972 234-0182