Classé Audio Delta Preamplifier and Delta Stereo Amplifier Review
Mark Gusew is blown away by this classy preamp/power amplifier combination…
Delta Preamplifier | Delta Stereo Amplifier
£9,999 | £11,999 respectively
Classé Audio has come a long way from its first stereo amplifier, the DR-2 launched in 1980 – but its love of Class A power has not changed. The Canadian company now operates under the umbrella of Sound United, along with brands such as Denon, Marantz and Bowers & Wilkins. And it's back with a brace of new products and something to prove. It has the resources, the team and the desire to produce world-class products that build on the company's illustrious heritage.
This is the third generation of the Classé Delta series amplifiers and easily the best yet. There are three new models, the Delta Mono and Stereo power amplifiers and the Delta Pre. The subject of this review is the Delta Stereo power amplifier at £11,999 and the Delta Pre preamplifier at £9,999. Not exactly spare change, so expectations are high…
Both new Delta amplifiers use the familiar one-piece heavy gauge aluminium curved front styling common to the previous generation of Classé products. They are finished in a dark charcoal finish called architectural grey. Many neat small touches add up to a highly accomplished design, including the custom Navcom feet with isolation control. The styling is modern and timeless, and the pair look fantastic stacked on top of one another. With either white on black VU meters or a touch panel display using a minimal amount of front panel buttons, it's a seriously sophisticated aesthetic.
The Delta Stereo is a powerful two-channel power amplifier with a rated output of 250W per side into 8 ohms, with the first 12.5W being pure Class A. This might not seem much, but many will struggle to push it beyond this figure with reasonably efficient modern loudspeakers. The front panel is dominated by the large and easy to read VU meters. A removable front louvre is complete with a cleanable air filter used as the inlet for the unit's so-called ICTunnel active cooling system. This is shaped for minimal noise and maximum cooling effect, with a thermostatically controlled variable speed fan which proved almost silent to those sitting a couple of metres away.
Care has been taken with the design and execution of the power supply of this amplifier, the company says, with the use of a custom hand-wound toroidal transformer with separate windings for left and right channels. Then there are the twenty-two individual four-pole Mundorf capacitors for 215,000uF of filtered energy potential. MOSFETs are used in the output stage.
Classé told me that one of the design goals for the amplifier was to make something that would easily drive B&W 800 Series speakers, which required a shift to a lower voltage, higher current design. The result is an amplifier capable of driving virtually any loudspeaker very well. Performance and durability are also mentioned as goals, and I get the sense that shortcuts were never an option with the design and execution of the new Delta series. This beast of an amplifier has a net weight of 46.4kg, so it is definitely a two-person job to set up.
In Australia, all Delta Series amplifiers come with a high-performance AC power cable made in the country and fully certified. The Delta Stereo sports both balanced and unbalanced inputs, and has two sets of high quality rhodium-plated copper five-way binding posts with Torque-Guard to avoid over tightening them. I used two sets of Wireworld cables to bi-wire connect my JBL HDI-3800 loudspeakers.
Another clever addition is the company's Controller Area Network, or CAN-Bus, which allows communication and control between the Stereo power amplifier and the Pre via the latter's touchscreen display. It can display status information, adjust display brightness and control standby and mute, among other things.
You could say that the Delta Pre was conceptually based on the earlier Classé CP-800 preamp, with similarly styled casework and a front touch panel handling the settings and controls. However, it has received a suite of upgrades to make it one of the most complete and comprehensive preamps that I've experienced. Its design brief included the need to support a wide variety of sources and also to run in Class A mode. Each of the sources – and there are quite a few – can be configured via the touch panel to optimise playback parameters and use digital tools for PEQ, Tone and Bass Management, or they can be bypassed in the interests of maximum signal purity.
There's a phono stage with user-configurable gain and loading, two pairs of balanced and unbalanced line inputs, an asynchronous USB input, three coaxial digital inputs, three optical digital inputs, an AES/EBU digital input and an Ethernet digital in. An optional HDMI card with AV inputs and outputs is available but was not fitted to my review sample. There are five configurable balanced outputs and five configurable unbalanced outputs, and these can be changed to subwoofer outputs with frequency, delay and slope controls, as well as nine-band parametric equalisation for each of the five output channels. All this happens in the digital domain.
I asked Dave Nauber, the company's Brand Director, about the choice and implementation of the onboard digital-to-analogue converters. He confirmed that AKM 4497 chips are used, adding that: “This is a stereo DAC, so there are four to run balanced in dual differential mode. Each leg of the balanced signal path is itself converted as a balanced signal. So the left channel, for example, is balanced (two signal paths) and each path is converted as a balanced signal, so four signal paths per channel times two channels (left and right) gives eight channels of D-to-A conversion.” Simple!
The layout of the circuit boards for both the pre and power amplifiers was done with the emphasis on directness, taking care to separate power paths to keep noise away from the signal. I'm told that this makes a huge difference to the overall sonic transparency of the unit. I love the use of high-quality Furutech rhodium-plated RCA connections, and this indicates the attention to detail taken. Although designed in Montreal, under Sound United's ownership, production has been moved to the high-end factory at Shirakawa in Japan, which is widely regarded as among the most advanced electronics production facilities in the world. As you would expect, overall build quality, metalwork and finish is absolutely first class.
Classé has an app available for both Apple and Android, which is a handy alternative for controlling volume and input functions, rather than using the remote control. The volume control on the Pre is analogue and has very fine 0.25dB steps, which, although accurate, I found to be at times slow and cumbersome when using the remote control to set the varying volume levels of different genres of music. Using the volume control on the app was often easier.
With an Ethernet port included in the Delta Pre, you would expect that it would stream music directly from the internet, and so it does with the correct app. I pressed the company for clarification. “The preamp not doing streaming relates to a limitation in the network module we chose; our focus is on performance rather than support of media players, which are constantly evolving. It is a renderer, so you can stream to it and get fantastic network and USB performance with its master clock mode. Now that we are part of Sound United we have access to a new network module and we will add media player functionality in the future. Units will be upgradeable.”
For my listening tests, I used the Classé Delta pair to drive my JBL HDI-3800 loudspeakers, and this proved an incredibly good pairing in every way. Feeding the preamp was a Mark Levinson No5101 SACD player and a Meitner MA3 Streamer/DAC.
The Delta Stereo power amplifier is all about control, power and authority. It takes a very tight grip of the loudspeakers and forces them to perform to a really high level. It always feels powerful and refined and well within itself at all times, even when playing at extreme volume levels. The system is very quiet with jet black backgrounds, which allow clean and well-defined notes with very fine detail to erupt and excite while remaining sweet, musical and balanced.
For example, Jets by Blur sounded incredibly powerful and dynamic, with the bass guitar having real grunt. Along with the kick drum, it impacted my chest and seemed strong enough to shake my room apart. Yet this Classé combo was also capable of playing very softly, as if it were background music, and still maintain the accuracy, tonality and overall balance.
The tonal balance is one of absolute naturalness and proficiency. Relentless Mind by the Jihye Lee Orchestra played with great texture and ease, and sounded relatively uncompressed – so the instruments were able to jump from the loudspeakers, adding to the realism. Depending on the choice of source and music, the Classé pair has the ability to seemingly convey all of the feel that was present on the day of the recording. It can have a hard or soft tonal character depending on the track, but is always colourful and interesting. The synth sequence of Baba O'Riley by The Who was really well defined, hanging in space and timed to perfection. I heard the individual texture and character of the kick drum, guitars, vocals and synth – which is just how it should sound.
The Delta pre/power pairing is truly full range. From the deepest low notes to soaring highs, every part of the frequency spectrum is fleshed out and uniform. Paper Trails by Darkside has a deep-voiced vocal that wasn't blended into a single mash of sound, yet displayed incredible clarity and definition. Both the bass notes and vocals were delivered with great separation and without confusion. The tonality and texture were maintained when played at a whisper or at crazy loud levels; the balance was constant. The midrange was a real highlight, equally proficient with either male or female vocals and especially natural. Acoustic instruments were a pleasure to listen to, too.
Another outstanding attribute of the Classé pair is the detail retrieval, its ability to dig deep and deliver. Listening to Massive Attack's Blue Lines, I heard obscure detail in the vocal and rhythm tracks that I hadn't picked up on before, despite knowing the mix well. With seemingly unending reserves of transparency, Lovely by Billie Eilish and Khalid had superb separation, both tonally and spatially between the two voices and between piano and violin. There was genuine nuance, resolution, focus and detail that made listening an absolute joy.
The Classé power amplifier has a remarkable way of taking control of the loudspeakers. Early prototypes were voiced using Bowers & Wilkins 800 Series speakers, and I hear they are a great pairing. My JBL HDI-3800s have never sounded so good, with clean and punchy full-range dynamics, fast transient response and tightly controlled bass. The rated damping factor is a very high 850 (at 1kHz, 8 Ohms), which likely has quite a bit to do with it, but unlike some amplifiers with a high damping factor, it doesn't sound overly closed in and nor does it clamp down on the dynamics.
Listening to the uncompressed Supreme Sessions 1 album proved a revelation, with natural micro and macro dynamics playing a significant part in the enjoyment of the album. Each pluck of a bass guitar string and press of a piano key sounded different to the others, adding realism and the feeling of listening to a live performance.
The output meters of the Stereo power amplifier indicates the power into an 8 ohm load and proved interesting to watch. I read that as a rule of thumb that when the pointer is below or left of vertical, the amplifier is operating in Class A. In my few weeks with it, I never saw the meters ever go beyond halfway and never to the 25W mark, despite the overt generosity of the volume. So it's safe to conclude that by far, the majority of my listening was in pure Class A mode, and boy did it sound sweet!
Freak, Go Home by Darkside is a track with lots of busy spatial panning from side-to-side, going well beyond apparent loudspeaker boundaries. It tests the elasticity of any system, and the Classé pair had no problems keeping up and accurately portraying a believable three-dimensional soundstage. Well recorded tracks came alive in my listening room, with Canto At Gabelmeister's Peak by Alexandre Desplat filling the soundstage with excellent centre fill and having real depth. Listening to the front-to-rear layers of instruments is like watching a movie with everything in its correct place, and with air and space between them all. And don't get me started with the superb handling of the very deep notes of the drum and pipe organ; it's bordering on faultless and amongst the best that I've ever heard.
LIVING THE STREAM
As earlier mentioned, Classé does not provide native Spotify Connect support, but if you have an iOS device, then you can choose the Delta Pre as your output device via Apple Airplay. I was able to easily connect using my iPad and was able to control the volume via the side up and down buttons. The same Airplay connectivity goes for Qobuz and Tidal, with even Master quality files able to be played, although the full benefit of MQA's unfolding doesn't properly occur via Airplay, with the front display stating that it is 44.1kHz regardless of the actual sample rate. The sound quality is fine, with little to complain about in isolation, but with a good external streamer like the Meitner MA3, it can sound even better. So this streaming ability is really for good quality casual listening, rather than for perfectionists.
More usable is Roon, with which I used my laptop to control music flow, but again Roon states that it was connected via Airplay. I found that it would have occasional dropouts and moments of pausing. Perhaps it's just my network, but there has to be a better workaround.
With the Classé Pre also being DLNA compliant, I found that certain apps would connect and allow streaming at full resolution. I used mconnectLite (also available on Android) to listen to Rhiannon Giddens' new album in all its original Qobuz 24-bit 96kHz glory without dropouts. The guitar and violin on Avalon immediately had more air around the instruments and was more three dimensional. This sounded much better, and far more indicative of the capabilities of the Classé Delta pair. So yes, you can certainly use the Delta Pre as a streaming audio source without the need for additional equipment, and it sounds incredibly good – just use a suitable app.
I used a Mark Levinson No5101 SACD player as a source and it sounded wonderful when using either balanced or unbalanced inputs. Unlike some balanced design amplifiers, the Delta Pre sounded amazing using either input, but as expected, was better via balanced. Using the coaxial digital output of the No5101 and going into the Delta Pre's internal showed off its sublime digital sound quality. It comprehensively bested the internal DAC of the No5101 SACD player, with Anabasis by Dead Can Dance having more detail, a larger and deeper soundstage and a more organic presentation. This is typical of the sonic characteristics of AKM 4497 DAC chips over ESS ES9026PRO chips, in my experience.
To test the Delta Pre's internal phono stage, I connected my modified Victor QL-Y7 direct-drive turntable, with Origin Live Silver tonearm and Hana SL low output moving coil cartridge. It was dead easy to set the gain and loading via the touch panel, and markedly superior to removing panels and adjusting banks of dip switches. The settings can also be changed on the fly, which is very useful. Incidentally, the phono stage takes a few minutes to warm up before it sounds right, even if the preamp is left permanently switched on but playing line level inputs.
I cued up one of my favourite albums, the Sheffield Labs pressing of James Newton Howard & Friends, which has startling attack and dynamics and is so much better than the digital versions. L'Daddy has some of the most aggressive snare hits I've heard recorded, and the inbuilt phono stage didn't sanitise it one bit. I played the track for one of my mates, and he literally jumped when I started the track with a generous volume setting. Tonal balance and timing coherence was very good, along with a large soundstage that went well beyond the loudspeakers. Although it lacks some of the transparency and naturalness that a more expensive separate outboard phono stage is capable of delivering, its sound is a great fit with the Pre and a welcome addition.
Classé's new Delta Pre and Stereo amplifiers are a technical tour de force, with flawless performance, handling both digital and analogue sources with equal finesse. The former's flexibility and capability is phenomenal, and it's obvious that much care has gone into the design and manufacture of this pair with the overall build quality and finish up to the highest standards available anywhere. Overall then, I have a newfound respect for Classé – quite honestly, there is no aspect of the sonic performance that I can criticise. This combination has abilities well beyond the asking price, so is heartily recommended.
Starting his first audio consultancy business in the early 80’s whilst also working professionally in the electronics industry, Mark now manages a boutique audio manufacturer.
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