Audio T Verdict
The Black Rhodium Operetta Digital is a high-quality 75-ohm coaxial cable for connecting compatible digital sources, transports and DACs.
Its silver-plated conductors are surrounded by low-loss insulation, a microphony-reducing conductive layer, silver-plated copper-braid screening and additional protection against EMI and RFI.
Audio T offers one-metre BNC-to-BNC and RCA-to-BNC versions, allowing Operetta Digital to connect equipment with different coaxial socket arrangements.
Black Rhodium Operetta Digital Cable
The Black Rhodium Operetta Digital is designed to carry an S/PDIF coaxial digital audio signal from compatible source equipment to a digital-to-analogue converter, amplifier or receiver.
It is aimed at capable Hi-Fi systems where a separate CD transport, streamer or digital source is being used with an external DAC.
Operetta Digital is hand-assembled at Black Rhodium’s factory in Derby using a carefully developed combination of conductors, insulation, screening, vibration control and factory-fitted connectors.
75-Ohm Coaxial Digital Design
Operetta Digital is manufactured as a 75-ohm coaxial digital audio cable.
This impedance is associated with conventional coaxial S/PDIF connections and is intended to maintain the integrity of the digital signal between compatible source and receiving equipment.
Both components must provide coaxial digital sockets. The cable does not convert between coaxial, optical, USB or HDMI formats.
Selectable Connector Arrangements
Audio T currently offers Operetta Digital in two one-metre configurations:
Select the version that matches the coaxial digital output on the source component and the coaxial digital input on the receiving component.
Do not select the cable by appearance alone. Check the socket type and function in both equipment manuals before ordering.
Check Both Ends Before Ordering
An RCA socket has a central hole surrounded by a circular outer contact. A BNC socket uses a bayonet-style connection with locking slots.
The sockets must also be labelled for coaxial digital audio. Analogue RCA and aerial-style BNC sockets may look compatible while serving completely different functions.
RCA-to-BNC Configuration
The mixed-termination version has an RCA connector at one end and a BNC connector at the other.
It is suitable where the source and receiving component use different coaxial digital socket types.
Because Operetta Digital has a defined signal direction, confirm which connector is required at the source end and which is required at the receiving end before placing the order.
BNC-to-BNC Configuration
The BNC-to-BNC version is fitted with Black Rhodium BNC connectors at both ends.
BNC connectors use a bayonet-locking mechanism that helps create a secure and repeatable connection with compatible sockets.
Black Rhodium fits its BNC connectors with gold-plated centre pins for resistance to tarnishing and reliable long-term contact.
Single Digital Cable
Operetta Digital is supplied as one cable for one coaxial digital connection.
Unlike an analogue stereo interconnect pair, a single S/PDIF cable carries the complete digital data stream, including both left and right audio channels.
A second cable is only required when making an additional independent digital connection.
One-Metre Standard Length
The versions currently offered by Audio T measure one metre.
This length suits many systems where the transport, streamer or digital source is positioned on the same equipment rack as the DAC or amplifier.
Measure the complete route before ordering and allow enough length for gentle curves without placing tension on the equipment sockets.
Silver-Plated Conductors
Operetta Digital uses silver-plated conductors within its coaxial construction.
Black Rhodium selected this conductor arrangement for the transmission of high-frequency digital signals and combines it with several layers of insulation and screening.
The manufacturer does not currently publish the base conductor material, conductor diameter or conductor cross-section, so specifications from other Black Rhodium cables should not be applied to Operetta Digital.
Low-Loss Dielectric Material
The conductors are enclosed within a low-loss dielectric material.
The dielectric electrically separates the signal conductor from the surrounding layers and forms an important part of the cable’s 75-ohm coaxial construction.
Black Rhodium does not identify the exact dielectric material used in the current public specification.
Conductive Microphony-Reducing Layer
A conductive layer is applied outside the dielectric material.
Black Rhodium uses this layer to help reduce microphony, where mechanical movement or vibration can influence the behaviour of the cable.
This layer works alongside the outer vibration-damping braid rather than acting as the cable’s only form of mechanical control.
Silver-Plated Copper-Braid Screen
The internal cable assembly is screened with a silver-plated copper braid.
This braided screen helps protect the digital signal from external electrical and radio-frequency interference produced by surrounding equipment.
A plastic sheath covers the braided screen and separates it from the cable’s additional screening and outer covering.
Additional EMI and RFI Screening
Further screening is applied outside the primary silver-plated copper braid.
This is intended to reduce the influence of electromagnetic interference and radio-frequency interference within a modern audio system.
Potential sources of interference can include:
- Wi-Fi routers and wireless network equipment
- Computers and network switches
- Televisions and games consoles
- Switch-mode power supplies
- Phone and laptop chargers
- LED lighting and dimmer switches
- Mains cables routed close to the digital cable
Where practical, avoid running the digital cable tightly alongside mains leads for its entire length.
Vibration-Damping Black Braid
The completed cable is covered with an attractive black woven braid.
Black Rhodium uses this outer braid to help damp unwanted vibration while providing additional protection for the internal construction.
The braid should not be removed, cut, crushed beneath equipment or repeatedly bent at the same point.
Directional Cable Construction
Operetta Digital has a defined source-to-DAC direction.
A printed heatshrink label identifies the direction by reading from the source or CD transport towards the DAC.
Install the cable so that the wording follows the signal path. This is particularly important when selecting the mixed RCA-to-BNC version.
Follow the Printed Direction
Locate the printed heatshrink label before installing the cable.
The label should read in the direction that the digital signal travels, from the source component’s output towards the DAC or amplifier’s input.
Connecting a CD Transport to a DAC
Switch both components off before making or changing the connection.
Connect the correctly oriented source end to the CD transport’s coaxial digital output, then connect the other end to the DAC’s coaxial digital input.
Switch the equipment back on and select the corresponding coaxial input on the DAC.
Connecting a Streamer to a DAC or Amplifier
Operetta Digital can also connect a compatible network streamer or music server to an external DAC or amplifier with a coaxial digital input.
The streamer must provide a coaxial S/PDIF output using the connector selected, and the receiving component must provide the corresponding input.
Some source components require their digital output to be enabled or configured through a setup menu.
Digital Format Compatibility
The cable provides the physical connection between the source and receiving component.
The available sampling rates, bit depths and audio formats are determined by the connected equipment rather than by the cable alone.
Confirm that the source can output a format accepted by the DAC, amplifier or receiver.
Not an Optical Cable
Operetta Digital carries an electrical coaxial signal and cannot connect to optical Toslink sockets.
Where either component provides only an optical connection, a suitable optical cable or active digital-format converter will be required.
Not a USB or HDMI Cable
The cable cannot connect USB audio sockets, HDMI ARC or HDMI eARC connections.
Use the correct digital cable type for the inputs and outputs provided by the equipment.
Not an Analogue Interconnect
Operetta Digital is designed for coaxial S/PDIF signals rather than conventional analogue audio.
An RCA connector can be used for either analogue or digital signals, so check the socket labels carefully before installation.
For a stereo analogue connection, use a suitable left-and-right interconnect pair rather than a single Operetta Digital cable.
System Matching
Operetta Digital is intended for capable digital sources and DACs where the system is sufficiently revealing to benefit from its more advanced construction.
Black Rhodium positions it above the Allegro S Digital, using design principles developed during work on its higher-level digital cables.
The scale of any improvement will depend on the source, DAC, existing cable, power supplies and complete system setup.
Demonstration Recommended
At this level, comparing Operetta Digital with the existing coaxial cable is recommended.
A demonstration can help establish whether it provides a worthwhile improvement and confirm that the selected RCA or BNC terminations match the equipment.
It also provides an opportunity to compare coaxial digital with any alternative optical, USB or network connections offered by the system.
Installation Guidance
- Switch both components off before changing digital cables
- Confirm that both sockets carry coaxial S/PDIF digital audio
- Select the correct RCA-to-BNC or BNC-to-BNC configuration
- Follow the direction shown by the printed heatshrink label
- Connect the source output to the receiving component’s input
- Push RCA connectors straight into compatible sockets
- Insert and lock BNC connectors using the bayonet mechanism
- Hold the connector body when disconnecting the cable
- Avoid sharp bends immediately behind the connectors
- Do not crush the cable beneath equipment or furniture
- Keep the cable away from strong heat sources and moisture
- Do not cut, shorten, open or reterminate the cable
Key Features
- Premium coaxial digital audio cable
- Designed for S/PDIF connections
- 75-ohm cable construction
- One-metre standard length through Audio T
- BNC-to-BNC termination option
- RCA-to-BNC termination option
- Silver-plated signal conductors
- Low-loss dielectric material
- Conductive layer for microphony reduction
- Silver-plated copper-braid screen
- Additional EMI and RFI screening
- Plastic sheath over the primary screen
- Black vibration-damping outer braid
- Directional source-to-DAC construction
- Printed directional heatshrink label
- Gold-plated centre pins on the BNC connectors
- Hand-assembled in Derby, England
- Black Rhodium lifetime product-function guarantee
Frequently Asked Questions
What does the package contain?
It contains one factory-terminated, one-metre Black Rhodium Operetta Digital cable in the selected connector configuration.
Which connector options are available from Audio T?
Audio T currently lists BNC-to-BNC and RCA-to-BNC versions.
Is Operetta Digital supplied as a pair?
No. It is supplied as a single cable because one coaxial S/PDIF connection carries the complete digital audio data stream.
What is the cable’s impedance?
Operetta Digital is manufactured as a 75-ohm coaxial digital cable.
What conductor material does it use?
Black Rhodium specifies silver-plated conductors but does not currently publish the underlying conductor material or dimensions.
Is the cable screened?
Yes. It uses a silver-plated copper-braid screen together with additional screening intended to reduce EMI and RFI.
What is the conductive layer for?
Black Rhodium applies a conductive layer outside the dielectric to help reduce microphony within the cable.
Is the cable directional?
Yes. A printed heatshrink label identifies the intended source-to-DAC direction.
Can it connect an RCA output to a BNC input?
Yes, when the correctly oriented RCA-to-BNC version matches the output and input sockets on the connected equipment.
Can it connect two BNC sockets?
Yes. Select the BNC-to-BNC version where both the source output and receiving input use compatible BNC sockets.
Are the BNC pins gold plated?
Yes. Black Rhodium specifies gold-plated centre pins for its Operetta Digital BNC connectors.
Can it connect to an optical input?
No. Optical Toslink and electrical coaxial S/PDIF are different connection formats.
Where is Operetta Digital assembled?
It is hand-assembled at Black Rhodium’s factory in Derby, England.
What guarantee is included?
Black Rhodium guarantees that its cables will fulfil their advertised function for the lifetime of the product, subject to its guarantee conditions.
Related Black Rhodium Products and Audio T Guides
Why Buy From Audio T?
- Independent advice from experienced Hi-Fi specialists
- Help identifying compatible RCA and BNC digital sockets
- Source, transport and DAC system matching
- Advice choosing coaxial, optical, USB or HDMI connections
- Connector-direction and compatibility checks
- Digital cable demonstrations where available
- Click and Reserve from participating stores
- Nationwide UK delivery on eligible products
- Ongoing after-sales support
Contact your local Audio T store to arrange a demonstration or confirm the correct Operetta Digital connector arrangement for your source and DAC.