Audio T Verdict
The Cyrus 40 PSU is more sophisticated than a conventional fixed-output external power supply. Its five independently controlled supplies allow it to adapt to the needs of different compatible 40 Series components.
Depending on the connected product, it can reinforce amplifier power rails, separate sensitive analogue and digital circuitry, power a CD player’s clock and motors, or supply the analogue stages of a streamer.
It is a carefully integrated upgrade rather than a universal mains accessory. For owners of a compatible Cyrus 40 Series component, it provides a clear system-development route without replacing the original product.
Cyrus 40 PSU External Power Supply
The Cyrus 40 PSU is an intelligent external power-supply upgrade for compatible Cyrus products fitted with a rear connection marked “USE 40 PSU ONLY”.
It contains five independent power supplies and an onboard microprocessor that communicates directly with the connected component through the supplied multi-way power interconnect.
The 40 PSU then configures its outputs automatically according to the requirements of the host product. There are no operating modes to select and no internal modifications are normally required.
Check Compatibility Before Connecting
The 40 PSU must only be connected to Cyrus products carrying a dedicated rear socket marked “USE 40 PSU ONLY”.
It must not be connected to a PSX-R, PSX-R2 or PSU-XR socket. Only the dedicated power interconnect supplied with the 40 PSU should be used.
Five Independent Power Supplies
Rather than providing one fixed output, the 40 PSU contains five separate supplies capable of supporting digital, low-voltage analogue and higher-consumption analogue circuitry.
- A high-capacity logic supply for compatible digital circuitry
- Two fixed-voltage supplies for sensitive low-voltage analogue stages
- Two variable high-capacity supplies for low or high-consumption analogue circuits
- Regulated variable outputs covering a wide voltage range
- Higher unregulated settings for demanding circuits such as power-amplifier stages
The available outputs allow one power-supply platform to be configured differently for an amplifier, CD player, streamer or phono stage.
Automatic Product Recognition
The 40 PSU and connected Cyrus component communicate through the multi-way power cable.
Once connected, the PSU identifies the host product and selects the correct output configuration automatically. Standby operation and status-indicator brightness are also controlled by the connected component.
There are no front-panel controls. A single status indicator confirms standby, operation, firmware information and any detected fault condition.
Currently Compatible
- Cyrus 40 AMP
- Cyrus 40 CD
- Cyrus 40 ST
- Cyrus 40 PPA
- Future Cyrus products marked “USE 40 PSU ONLY”
Not Compatible With
- Cyrus Classic PSX-R2 products
- Cyrus XR products using the PSU-XR
- Cyrus equipment without a 40 PSU connection
- Products from other manufacturers
- More than one host component at a time
Upgrading the Cyrus 40 AMP
When connected to the
Cyrus 40 AMP
,
the 40 PSU supplies the preamplifier section and reinforces the main power-amplifier supply rails.
This leaves the amplifier’s internal supply with less work to perform and allows it to concentrate more heavily on the DAC section.
Cyrus also specifies an increase in rated output from 100W to 113W per channel into 6O when the external supply is fitted.
The purpose of the upgrade extends beyond the additional wattage, with the separation and increased capacity of the supplies intended to improve control, timing and clarity.
Upgrading the Cyrus 40 CD
With the
Cyrus 40 CD
,
the external supply powers the master clock, disc-drive motors and analogue side of the DAC.
The transport motors continually adjust their operating speed and can create electrical noise within a CD player. Moving their supply duties to the external PSU helps separate this activity from more sensitive audio circuitry.
The internal supply remains responsible for the digital side of the DAC, creating greater separation between the player’s digital and analogue sections.
Upgrading the Cyrus 40 ST
When connected to the
Cyrus 40 ST
,
the 40 PSU powers the analogue side of the DAC and the BluOS network module.
This provides those sections with their own clean and stable supply, reducing the load placed on the streamer’s internal power arrangements.
The network module and analogue output circuitry perform very different tasks, so the 40 PSU’s independently configured outputs allow each area to receive power suited to its requirements.
Compatible with the Cyrus 40 PPA
The
Cyrus 40 PPA
also provides a dedicated 40 PSU connection.
A phono stage handles exceptionally small cartridge signals, making power-supply noise, grounding and circuit separation particularly important.
Cyrus does not currently publish the same section-by-section allocation for the 40 PPA as it does for the amplifier, CD player and streamer, but the phono stage automatically recognises and configures the external supply.
One PSU Per Component
A single 40 PSU connects to one compatible Cyrus component.
A system containing a 40 AMP and 40 ST would therefore require two separate power supplies if both products were to be upgraded.
The 40 PSU cannot divide its outputs between two components or be switched between products while the system is powered.
Both Products Remain Connected to Mains Power
The 40 PSU works alongside the power supply already installed inside the host component rather than replacing it completely.
Both products must therefore remain connected to suitable mains sockets. The system should be disconnected from mains power before the interconnect is fitted, removed or changed.
The power cable between the two products is non-reversible and should reach without being stretched or placing strain on either connector.
Automatic Standby Control
The PSU follows the power state of the connected product automatically.
When the host enters standby, the 40 PSU also returns to standby. When the host is switched on, the PSU activates the required supplies and its indicator changes to match the connected component.
Automatic standby settings are managed through the host product rather than the PSU itself.
Firmware Updates
A rear Mini USB service connection allows the 40 PSU firmware to be updated when Cyrus releases compatibility improvements, operational changes or additional features.
The required firmware and instructions are provided through Cyrus support. Updates to the PSU may also require the connected 40 Series component to be updated at the same time.
The service connection is not an audio input and cannot be used for computer music playback, USB storage or network access.
40 Series Aluminium Casework
The PSU uses the same 220mm-wide aluminium chassis and ribbed upper section as the matching Cyrus 40 Series components.
Its compact width allows it to sit beside another 40 Series product on many conventional equipment shelves, provided sufficient ventilation and support are available.
At 9.4kg, it requires a strong and level shelf. Cyrus advises against positioning it underneath another component or on a surface that obstructs cooling.
40 PSU, PSX-R2 or PSU-XR?
Cyrus uses different external power supplies for different product families, and the connections are not interchangeable.
The 40 PSU is intended for compatible 40 Series products marked “USE 40 PSU ONLY”. The Classic PSX-R2 is used with compatible Classic and earlier Cyrus products carrying a five-pin PSX-R socket.
The PSU-XR is designed for compatible XR Series equipment. The correct supply must always be selected according to the connection fitted to the host product.
Key Features
- Intelligent external power supply for compatible Cyrus products
- Five independently configured power supplies
- Onboard microprocessor control
- Automatic communication with the connected component
- High-capacity logic supply for digital circuitry
- Two fixed-voltage analogue supplies
- Two variable high-capacity analogue supplies
- Regulated and unregulated output configurations
- Compatible with the Cyrus 40 AMP
- Compatible with the Cyrus 40 CD
- Compatible with the Cyrus 40 ST
- Compatible with the Cyrus 40 PPA
- Automatic standby and status control
- Mini USB firmware-update connection
- Power interconnect and firmware cable included
- Matching Cyrus 40 Series aluminium casework
- Five-year manufacturer warranty
Frequently Asked Questions
Which products are compatible with the Cyrus 40 PSU?
It works with Cyrus components carrying a rear connection marked “USE 40 PSU ONLY”, including the 40 AMP, 40 CD, 40 ST and 40 PPA.
Does it work with the Classic PSX-R2 connection?
No. The 40 PSU, Classic PSX-R2 and PSU-XR use different connections and must not be interchanged.
Can one 40 PSU upgrade two components?
No. One PSU is required for each compatible Cyrus component being upgraded.
Does the connected product still need mains power?
Yes. The 40 PSU works alongside the host product’s internal supply, so both components remain connected to mains power.
Does it require manual configuration?
No. Its microprocessor communicates with the connected product and selects the required power-supply configuration automatically.
Does it increase the power of the 40 AMP?
Yes. Cyrus specifies an increase from 100W to 113W per channel into 6O, alongside changes to how the amplifier’s internal sections are powered.
Are the connection cables included?
Yes. The supplied accessories include the mains cable, dedicated power interconnect, firmware-update cable and quick-start guide.
Is the Mini USB connection an audio input?
No. It is a service connection used for firmware updates and cannot be used for music playback.
Does the PSU have its own controls?
No. Standby, configuration and indicator brightness are controlled automatically by the connected Cyrus component.
Why Buy From Audio T?
- Experienced Cyrus system specialists
- Compatibility checks before purchase
- In-store comparisons through participating branches
- Advice prioritising upgrades within a Cyrus system
- Correct power-interconnect installation guidance
- Firmware and system setup support
- Help planning multi-component 40 Series systems
- Ongoing technical and servicing assistance
Contact your local Audio T store
to confirm compatibility or arrange a demonstration of the Cyrus 40 PSU with your chosen 40 Series component.