As much as Roksan's Attessa Streaming Amplifier impressed me when I reviewed it a couple of years ago, this brand new streaming integrated from the company's flagship Caspian Series 4G is on another level. Without wishing to start this review with my verdict, I must tell you that the standard of music reproduction it delivers belies its asking price.

What makes it even more impressive, though, is how a single, elegantly styled unit can deliver high-resolution digital audio of a quality that was once the preserve of multi-box systems with a five-figure price tag. Those who don't require the streaming option can buy the Caspian Integrated for a bit less and experience the same fine audio quality and strong power output of (a claimed) 105W RMS into 8 ohms and 200W into 4.

UP CLOSE

Aside from the onboard streaming module, the Caspian Series 4G amplifiers offer two line-level RCA analogue inputs as well as a balanced XLR input. Vinyl lovers are catered for with a moving magnet phono stage (53dB gain with +/- 6dB adjustment) via a third pair of RCAs. While some might bemoan the lack of moving coil capability, I reckon Roksan has made the right choice. Some users may not require turntable connectivity at all, while those tempted to try will probably dip their toe in with a magnetic cartridge. Analogue addicts will likely already have a standalone phono stage or use a step-up transformer with their MC.

The back panel features two coaxial and two optical digital inputs, plus Bluetooth Audio. This streaming amplifier adds HDMI eARC and, of course, BluOS for the excellent app that gives access to a multitude of streaming platforms; Qobuz is my chosen service for hi-res. Three analogue outputs from the preamp section are provided, two from RCA and a third from balanced XLR, plus Gigabit Ethernet RJ45, Wi-Fi 5, Wi-Fi 4, BLE, 12v trigger and Wired IR port. I use the RJ45 socket for a more stable wired connection to my router than wireless for streaming.

For this new Caspian Streaming Amplifier, Roksan incorporates its Rapture DAC technology. The company says that its differential current-conveyor topology has several measurable advances over digital-to-analogue reconstruction using op-amp ICs. All versions use a new Class AB power amplifier architecture called Euphoria. This features individual power supplies for both current and voltage amplifiers, which are said to keep intermodulation and harmonic distortion flat across frequency and load. The preamplifier section is fully balanced with what Roksan describes as a novel ground-switching input design that keeps crosstalk between connected devices at a low level.

In the middle of the facia sits a large volume control that uses a hybrid digital-analogue volume control algorithm to facilitate tone control and system matching. Many other features can be found within the Caspian's DSP engine, accessed via the MaestroUnite app. This facilitates four key technologies, namely Intelligent Tone, Intelligent Boundary, Intelligent Speaker and Intelligent Phono. There is a good deal of user adjustment, including a few features worth pointing out besides the obvious ones, such as balance control.

For example, Safe Volume is a useful tool to protect your loudspeakers and hearing. If the amp's volume is set to a very high level, it will automatically be reduced when the unit is next switched on. And for the many who don't find it necessary to keep their equipment powered up permanently, an Auto Standby mode will put the amp into standby after twenty minutes of inactivity. Intelligent Loudness subtly adjusts the bass response at lower volume levels. This works well and is quite different from the 'loudness' buttons on cheap amps of yore, which merely injected boom and tizz into the sound.

Subwoofer users will be pleased to hear that not only can the crossover frequency be precisely tailored, but any unwanted phase cancellations (due to the position of the sub) will be prevented by using the 'polarity invert' control. The supplied remote control is lovely, allowing the adjustment of volume and so on; the only other fascia controls are a trio of push-buttons for play/pause and skip back or forwards, situated to the left of the volume control. To its right is the high-resolution OLED display that indicates the volume level.

THE LISTENING

This amplifier sounds clean, clear and precise and has more than ample power on tap. It is also very well controlled, giving the sort of sound that's the polar opposite of the rather rose-tinted Leak valve power amps I usually use in my main system. Transients have razor-like precision, which shines a light on the leading edges of musical notes. Yet this doesn't mean its overall character is hard-edged or brittle, as there is not a hint of grain. All of which makes for a rhythmically engaging sound that's never less than great fun.

For example, Radiohead's classic OK Computer highlights not only the crisp percussion on tracks such as Paranoid Android but also the vice-like grip throughout the frequency range as the song gets busier. Lesser amps often struggle to keep things in order with this type of material, especially those designed to add mid-bass warmth into the mix. Yet there is no spurious fleshing-out of the bottom end from the Caspian, meaning it doesn't flatter older recordings. It certainly is not bass-light, however, nor does it shy away from delivering thunderous low frequencies if they are present on the recording.

Radiohead's Karma Police features a thickly recorded electric bass that can render the track ponderous without the firm control on offer here. Instead, the low end is muscular yet agile, making bass lines easy to follow. This refined sense of control is evident throughout the midrange, too, which is also very well-ordered. Detail levels are superb with well-recorded music. However, the transparency and honesty of the amp takes no prisoners when presented with poorly mixed tracks. Given a good stereo recording, however, the listener is rewarded with a gloriously capacious three-dimensional soundstage.

While the Caspian majors on precision and detail, it is neither mechanical nor austere in nature. Playing Marvin Gaye's timeless What's Going On reveals how it revels in rhythms while also expressing the emotion both within the music and from the impassioned vocals. Stage depth is enveloping here, effortlessly displaying the stereo panning and chamber reverb evident throughout the album.

Switching to vinyl to spin some of my beloved Blue Note mono jazz LPs from the nineteen sixties, it's immediately clear that Roksan has cut no corners with the onboard phono stage. Using my Hana ML moving coil cartridge through a transformer into the Caspian's moving magnet phono stage, the clarity of the amp is in no way compromised. The timbre of the acoustic instruments is utterly convincing, with the trip-hammer transients making the saxophone playing of the likes of Joe Henderson and Wayne Shorter a really tactile experience. And as the amp is seriously deft in the way it deals with dynamic shifts, the presentation is all the more lifelike.

THE VERDICT

Roksan's latest Caspian Series 4G Streaming Amplifier is an excellent choice for those with a passion for hi-res streaming, offering superb sound without the need for multiple boxes. All you need is a pair of quality loudspeakers, such as those produced by Roksan's parent company, Monitor Audio, for example. Audiophiles who don't limit their music consumption to streaming can make use of the Caspian's classy-sounding analogue and digital inputs, not forgetting its fine phono stage for vinyl replay. All of this comes in a very well-built and elegant package. Even though there's no shortage of highly accomplished integrated amplifiers at its price, this new design still stands out – and, as such, is well worth auditioning.

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