Audio T Verdict
The Roksan Caspian 4G Streaming Amplifier brings together substantial Class A/B amplification, high-resolution BluOS streaming and an unusually comprehensive selection of analogue and digital connections.
Its dual-mono Euphoria amplifier delivers 105W per channel into 8 ohms and 200W per channel into 4 ohms. This gives the Caspian the power and current delivery needed to partner a broad range of high-quality standmount and floorstanding loudspeakers.
The built-in BluOS platform handles network streaming, internet radio, compatible USB storage and multiroom playback at resolutions up to 24-bit/192kHz. AirPlay 2, Spotify Connect, TIDAL Connect and Roon Ready support provide further ways to access and control music.
HDMI eARC allows television audio to become part of the main Hi-Fi system, while the dual-mono balanced Rapture DAC accommodates optical, coaxial and network sources.
Vinyl has not been overlooked. The built-in moving-magnet phono stage offers three gain settings, helping the amplifier accommodate cartridges with different output levels without automatically requiring an external phono stage.
The balanced XLR input, RCA line inputs, configurable balanced and unbalanced outputs and subwoofer facilities give the Caspian considerably more flexibility than a typical all-in-one streaming amplifier.
It is not the smallest or least expensive route into BluOS, and customers who already own a preferred streamer may be better served by the standard Caspian 4G Integrated Amplifier. However, for somebody seeking a powerful premium amplifier, streamer, DAC, phono stage and television-audio hub in one enclosure, the Streaming Amplifier makes a convincing case.
Roksan Caspian 4G Streaming Amplifier
The Roksan Caspian 4G Streaming Amplifier combines a network music streamer, digital-to-analogue converter, pre-amplifier, moving-magnet phono stage and powerful stereo power amplifier.
Connect a suitable pair of passive loudspeakers and it can reproduce streamed music, television sound, vinyl, Bluetooth audio, compatible USB storage and conventional analogue or digital sources.
Control is available through the BluOS Controller app, Roksan MaestroUnite app, supplied aluminium remote control and the front-panel Dynamic Control Dial.
105W-per-Channel Class A/B Amplification
The Caspian produces 105W per channel into 8 ohms with both channels driven.
Output increases to 200W per channel into 4 ohms, giving the amplifier the ability to maintain control as loudspeaker impedance becomes more demanding.
A quoted power figure alone cannot guarantee compatibility with every speaker. Sensitivity, impedance behaviour, room size, listening distance and preferred volume should still be considered before purchase.
Dual-Mono Euphoria Amplifier Architecture
Roksan describes the Caspian power-amplifier design as its dual-mono Euphoria architecture.
The left and right amplification channels use independently arranged circuitry intended to reduce unwanted interaction between them.
This approach supports:
- Improved stereo separation
- More stable positioning of voices and instruments
- Greater control during complex musical passages
- Reduced channel-to-channel interference
- Consistent performance into demanding loudspeaker loads
The amplifier operates in Class A/B rather than using a Class D output stage.
Substantial 600VA Power Supply
A 600VA power supply supports the Caspian amplification stage.
Roksan specifies 36,400µF of reservoir capacitance per power-supply rail, providing stored energy for demanding musical peaks and changes in loudspeaker load.
The amplifier is rated with both channels driven rather than quoting output from a single channel under less representative conditions.
Rapture Digital-to-Analogue Conversion
Digital-to-analogue conversion is handled by Roksan's dual-mono balanced Rapture DAC architecture.
The DAC supports compatible two-channel PCM audio at resolutions up to 24-bit/192kHz.
Digital sources can be connected through:
- Two coaxial S/PDIF inputs
- Two optical S/PDIF inputs
- HDMI ARC and eARC
- BluOS network streaming
- Compatible USB storage
- Bluetooth audio
The Rapture DAC is used when a digital source is connected directly to the Caspian.
Two Coaxial Digital Inputs
Two coaxial S/PDIF inputs support compatible stereo PCM audio at resolutions up to 24-bit/192kHz.
These inputs can accommodate products such as:
- CD transports
- Network streamers
- Digital radio tuners
- Compatible television equipment
- Digital music servers
The Roksan Attessa CD Transport can be connected as a conventional digital source through its coaxial output.
Two Optical Digital Inputs
Two optical inputs provide further connectivity for compatible televisions, games consoles, streamers, disc players and other digital sources.
Optical input supports compatible two-channel PCM at up to 24-bit/192kHz.
Dolby Digital, DTS and other multichannel cinema formats should not be sent through an ordinary stereo digital input unless the connected source has first converted them to two-channel PCM.
HDMI ARC and eARC
The HDMI 2.0 ARC and eARC connection allows compatible television audio to play through the Caspian and its connected loudspeakers.
This provides a high-quality alternative to using the television's internal speakers or a separate soundbar.
Depending on the television and its control settings, the television remote may also operate everyday volume and power functions.
Check the Television Audio Format
A connected television should normally be configured to output a compatible two-channel PCM or LPCM signal.
Multichannel Dolby or DTS output may not be reproduced correctly by a two-channel Hi-Fi amplifier.
BluOS High-Resolution Streaming
BluOS is built directly into the Caspian Streaming Amplifier.
The BluOS Controller app can be used to browse compatible streaming services, internet radio, podcasts, USB storage and music stored on a local network.
Supported playback reaches up to 24-bit/192kHz where the source material, service and connection allow.
Common supported audio formats include:
- MP3
- AAC
- WMA
- WMA Lossless
- OGG
- ALAC
- Opus
- FLAC
- WAV
- AIFF
- MQA
Converted DSD playback is supported through the BluOS desktop application rather than as native direct DSD processing.
Streaming Services and Internet Radio
BluOS integrates a broad selection of compatible music and radio services within one control platform.
Availability can depend on the customer's country, chosen service, subscription level and current BluOS support.
Third-party playback and control options include:
- Apple AirPlay 2
- Spotify Connect
- TIDAL Connect
- Roon Ready playback
Roon Ready
Roon Ready certification allows the Caspian to operate as a compatible network-audio endpoint within a Roon system.
Roon requires:
- A suitable Roon server
- An active Roon subscription
- A reliable home network
- A compatible controller device
Roon is not included with the amplifier and is operated separately from the standard BluOS Controller app.
BluOS Multiroom Playback
The Caspian can form part of a BluOS multiroom system containing as many as 64 compatible zones.
It can be grouped with supported products from Bluesound and other manufacturers that use the BluOS platform.
Different zones can play the same music in synchronisation or operate independently.
Network quality remains important, particularly where several zones are playing high-resolution material simultaneously.
Gigabit Ethernet and Wi-Fi
A Gigabit Ethernet connection is provided for wired network operation.
Ethernet is normally the preferred option where a suitable network cable can be routed to the system, as it avoids some of the interference and coverage issues associated with wireless networking.
Wi-Fi 5 is also available for BluOS network streaming where a wired connection is impractical.
USB Music Playback
A rear USB Type-A port accepts compatible FAT32 or NTFS storage devices.
Music stored on a suitable USB drive can be browsed and played through the BluOS Controller app.
The port is intended for supported storage and peripheral functions. It is not specified as a conventional USB computer-audio input.
Music Stored on a Network
BluOS can access compatible music libraries shared through the Server Message Block network protocol.
This can include music stored on:
- A compatible NAS drive
- A Windows computer
- A macOS computer
- Another correctly configured network-share device
The host device and network share must remain available whenever the stored music is being played.
Bluetooth Audio
Bluetooth provides a convenient way to play audio from a compatible phone, tablet or computer without opening the BluOS app.
Supported Bluetooth codecs include:
Roksan quotes a typical range greater than 15 metres, although walls, furniture, wireless congestion and the transmitting device can reduce this.
Moving-Magnet Phono Stage
A built-in moving-magnet phono stage allows a suitable turntable to connect directly to the Caspian.
The input uses a standard 47k-ohm and 100pF loading arrangement and provides three gain settings:
- Low: -6dB
- Mid: 0dB
- High: +6dB
This allows the input sensitivity to be adjusted for cartridges with different output levels.
Moving-Magnet Input Only
The Caspian Streaming Amplifier is officially specified with a moving-magnet phono input.
A conventional low-output moving-coil cartridge requires a suitable external moving-coil phono stage or step-up arrangement.
Do not connect a separate phono stage to the Caspian phono input. An external phono stage should be connected to one of the normal line-level inputs.
RCA and Balanced XLR Inputs
Two stereo RCA line inputs are provided for conventional analogue sources.
A balanced stereo XLR input is also available for compatible source equipment.
Suitable analogue sources can include:
- CD players
- External DACs
- Separate phono stages
- Network streamers
- Radio tuners
- Cassette decks
The maximum quoted analogue input level is 6.7Vrms.
Music Sense and AV Mode
The second RCA line input supports Music Sense and AV mode functions.
Music Sense can allow the amplifier to respond when an appropriate signal is detected.
AV mode can provide integration with a compatible home-cinema processor or receiver by configuring the input for the required system arrangement.
Use AV Mode Carefully
When a line input is configured for AV bypass or fixed-gain operation, the Caspian volume control may no longer limit the signal passing through that input.
Only connect a properly volume-controlled AV processor or receiver output and confirm the setup before playing audio.
Balanced and Unbalanced Outputs
The Caspian provides one balanced stereo XLR output and two stereo RCA outputs.
Depending on the selected configuration, these connections can support:
- Variable pre-amplifier output
- Fixed line-level output
- Low-pass-filtered subwoofer output
- An additional external power amplifier
- System expansion or recording equipment
The maximum quoted pre-amplifier output level is 3.9Vrms.
Adding a Subwoofer
One of the configurable analogue outputs can be assigned for low-pass-filtered subwoofer operation.
A suitable active subwoofer requires its own built-in amplifier and compatible line-level input.
Subwoofer performance will depend on correct adjustment of:
- Output level
- Crossover frequency
- Phase
- Room position
- Main-speaker bass response
Audio T can help compare direct loudspeaker bass with a correctly integrated active subwoofer.
Adding an External Power Amplifier
The variable pre-amplifier outputs allow the Caspian to control a compatible external power amplifier.
This can support system expansion where:
- Additional power is required
- The internal amplifier is being supplemented
- A different power amplifier is preferred
- A more advanced multi-amplifier system is being planned
Gain structure, connection type and loudspeaker wiring should be checked before combining amplifiers.
Hybrid Digital and Analogue Volume Control
The Caspian pre-amplifier uses a hybrid digital and analogue volume-control system.
Roksan specifies channel matching of better than 0.25dB, helping maintain a stable stereo image at different listening levels.
The pre-amplifier section is quoted with a signal-to-noise ratio greater than 108dB at its specified output level.
Dynamic Control Dial
The front-panel Dynamic Control Dial provides haptic feedback while controlling:
- Volume
- Input selection
- Power and standby functions
Separate front-panel buttons provide previous-track, play and pause, and next-track control for compatible sources.
Caspian 4G Remote Control
A 15-button infrared remote control is included.
Its bead-blasted and anodised aluminium casing is designed to match the finish and construction quality of the amplifier.
The remote provides direct access to commonly used inputs, presets, playback functions, volume and standby.
MaestroUnite Setup and Management
MaestroUnite is Roksan's setup and product-management application for compatible iOS and Android devices.
It can be used for:
- Initial product setup
- Input configuration
- Output configuration
- Advanced system settings
- Checking product information
- Installing over-the-air firmware updates
MaestroUnite and BluOS perform different jobs. MaestroUnite manages the amplifier and its settings, while BluOS handles music browsing, network playback and multiroom control.
Over-the-Air Firmware Updates
Firmware updates can be delivered through the network connection configured by MaestroUnite.
Updates may add features, improve compatibility or address operational issues.
The mains supply and network connection should not be interrupted while an update is being installed.
12V Trigger and Wired Infrared
A 12V trigger input allows compatible system components to coordinate power and standby operation.
A trigger passthrough connection is also provided.
The wired infrared input can be useful where the amplifier is installed inside furniture or another position where the front infrared receiver is not directly visible.
Aluminium Construction
The Caspian uses extruded and machined aluminium front and top panels.
Extruded aluminium heatsinks provide cooling for the Class A/B output stage.
The enclosure measures 93 x 432 x 378mm and weighs 15.5kg.
Its full-width design and black or silver finish options allow it to match other components within the Caspian 4G range.
Positioning and Ventilation
Place the amplifier on a firm, level and stable equipment support capable of safely carrying its 15.5kg weight.
Keep it away from:
- Enclosed shelves without ventilation
- Carpet and soft furnishings
- Radiators and other heat sources
- Direct sunlight
- Damp or humid locations
- Unstable furniture
- Excessive dust
Do not obstruct the aluminium heatsinks or place another heat-producing component directly on top.
Streaming Amplifier or Integrated Amplifier?
Choose the Streaming Amplifier When
- BluOS streaming is required
- Multiroom playback is important
- HDMI ARC or eARC is required
- Roon Ready playback is wanted
- AirPlay 2 is required
- Network and USB libraries will be used
- You want fewer separate components
Choose the Integrated Amplifier When
- You already own a preferred streamer
- HDMI television audio is unnecessary
- Analogue and conventional digital sources are the priority
- You prefer to upgrade the streamer separately
- A lower purchase price is preferable
- You want the same core amplification without BluOS
The Roksan Caspian 4G Integrated Amplifier shares the core Euphoria amplification, Rapture DAC, MM phono stage and extensive analogue connectivity without the built-in BluOS and HDMI eARC functions.
System Matching
Well Suited To
- Premium standmount or floorstanding loudspeakers
- Customers combining streaming, vinyl and television sound
- BluOS multiroom systems
- Roon-based music systems
- Systems requiring balanced analogue input
- Systems with an active subwoofer
- Listeners wanting fewer separate components
- Black or silver full-width Hi-Fi systems
Check Before Buying
- Loudspeaker sensitivity and impedance are appropriate
- The equipment support can carry 15.5kg
- There is sufficient ventilation around the heatsinks
- A moving-magnet rather than low-output moving-coil cartridge is being connected directly
- The network is suitable for high-resolution streaming
- The television can output compatible stereo audio
- The required streaming services are available through BluOS
- There is sufficient space for the 378mm cabinet depth and rear cables
Related Roksan Products and Audio T Guides
Key Features
- 105W per channel into 8 ohms
- 200W per channel into 4 ohms
- Class A/B amplification
- Dual-mono Euphoria architecture
- 600VA power supply
- Dual-mono balanced Rapture DAC
- PCM up to 24-bit/192kHz
- BluOS network streaming
- Up to 64 BluOS zones
- Gigabit Ethernet
- Wi-Fi 5 for BluOS
- USB storage playback
- Apple AirPlay 2
- Spotify Connect
- TIDAL Connect
- Roon Ready
- MQA support
- Bluetooth with SBC, aptX and AAC
- HDMI 2.0 ARC and eARC
- Two coaxial digital inputs
- Two optical digital inputs
- Two stereo RCA line inputs
- One balanced stereo XLR input
- Moving-magnet phono stage
- Three MM phono gain settings
- Balanced XLR pre-output
- Two stereo RCA outputs
- Configurable subwoofer output
- Music Sense on the A2 input
- AV mode on the A2 input
- Dynamic Control Dial
- MaestroUnite setup and updates
- 15-button aluminium remote
- 12V trigger input and passthrough
- Wired infrared input
- Black and silver finishes
- Five-year manufacturer warranty
Frequently Asked Questions
How much power does the Caspian Streaming Amplifier produce?
Roksan specifies 105W per channel into 8 ohms and 200W per channel into 4 ohms, with both channels driven.
Does it include network streaming?
Yes. BluOS high-resolution streaming is built directly into the amplifier.
Does it support Roon?
Yes. The Caspian Streaming Amplifier is currently listed as Roon Ready.
Does it support AirPlay 2?
Yes.
Can it play Spotify and TIDAL?
Yes. Spotify Connect and TIDAL Connect are supported, alongside the services integrated within BluOS.
Can it connect to a television?
Yes. HDMI ARC and eARC are built in, and optical digital inputs are also available.
Can I connect a turntable directly?
Yes, when the turntable uses a suitable moving-magnet cartridge and is not already outputting line level.
Can I connect a moving-coil cartridge directly?
A conventional low-output moving-coil cartridge requires a suitable external moving-coil phono stage or step-up arrangement.
Does it have balanced inputs?
Yes. One balanced stereo XLR input is provided.
Does it have balanced outputs?
Yes. One balanced stereo XLR pre-amplifier output is provided.
Can I add a subwoofer?
Yes. The configurable analogue outputs include low-pass-filtered subwoofer operation.
Can I add an external power amplifier?
Yes. Variable balanced and unbalanced pre-amplifier outputs are available.
Can it play music from a USB drive?
Yes. A compatible FAT32 or NTFS USB storage device can be connected and browsed through BluOS.
Can it play music stored on a NAS drive?
Yes, when the music is available through a correctly configured SMB network share.
What is the maximum streaming resolution?
BluOS and compatible digital inputs support audio at up to 24-bit/192kHz.
Does it support Bluetooth?
Yes. SBC, aptX and AAC codecs are listed.
What is the difference between the Streaming and Integrated Amplifiers?
The Streaming Amplifier adds BluOS, HDMI eARC, network connectivity, USB storage playback, AirPlay 2 and Roon Ready support to the core Caspian amplifier platform.
Is a remote control included?
Yes. A 15-button infrared remote with an aluminium casing is supplied.
Which finishes are available?
Black and silver.
What warranty is provided?
Roksan currently specifies a five-year manufacturer warranty, subject to its applicable registration and warranty terms.
Why Buy From Audio T?
- Roksan Caspian 4G demonstrations
- Streaming and Integrated Amplifier comparisons
- Loudspeaker compatibility and system matching
- BluOS network and multiroom setup
- Roon and AirPlay configuration guidance
- Television and HDMI eARC setup
- Moving-magnet cartridge compatibility checks
- Turntable and external phono-stage matching
- Subwoofer setup and integration
- Balanced and unbalanced connection advice
- CD transport and digital-source matching
- MaestroUnite setup assistance
- Firmware-update guidance
- Equipment-support and ventilation advice
- Part exchange may be available on suitable existing equipment
- Roksan warranty guidance
- Ongoing product and system support
Contact your local Audio T store to arrange a demonstration or discuss loudspeaker, source and system matching for the Roksan Caspian 4G Streaming Amplifier.