Hardware Reviews

Cyrus PSU-XR opens up the i9-XR

Cyrus PSU-XR review

Cyrus Audio PSU-XR power supply

The Cyrus PSU-XR is the latest in a long line of power supply upgrades for Cyrus, the Huntingdon, England based company were among the very first to offer this form of upgrade in the form of the original PSX model from the ‘80s. The PSX has since evolved into the PSX-R2,which is still offered as an upgrade for the Cyrus Classic range of components. The PSX range communicates with its host via analogue sensors and regulators. By contrast communication between the latest Cyrus PSU-XR and its host is controlled via a microprocessor. There is a significant price difference between the PSX-R2, at £995 and the PSU-XR at £2,395. As we shall discover, the latter contains far more advanced technology, which promises significant sonic gains.

The clever bits

The Cyrus PSU-XR is designed to fit in visually with the rest of the Cyrus XR range, no surprises here. I like the way that the LED flashes different colours to denote the installed firmware version at start up but I was surprised that there is no earth pin in what looks otherwise like a standard IEC power inlet. I gather this is usual for Cyrus equipment and will doubtless be due to the design of the PSU. The Cyrus PSU-XR contains no less than five independent power supplies with each section operating independently. For example, the current delivered to the host product’s power section to cope with a transient or dynamic swing should not affect the power sent to the preamp section. The output voltage is digitally synthesised, which Cyrus claim eliminates virtually all mains-borne noise. Each of the five power supplies is separately grounded to avoid noise contamination.

Cyrus PSU-XR review

The Cyrus PSU-XR is compatible with much of the XR range of components, a notable exception being the i7-XR integrated amplifier. The host component communicates with the PSU-XR via a 15-pin connector, which must be screwed into place to avoid accidental disconnection. Impressively, the host product instructs the PSU-XR where to send the power and how much is required. For example, the PSU-XR can also deliver unregulated power to cope with dynamic peaks as the power-amp section demands. When connected to the Pre-XR, the PSU-XR takes over powering the analogue preamp stage, which allows the Pre-XR’s own PSU to supply to the DAC section. Four of the PSU-XR’s five output stages are employed when paired with a CDi-XR CD Player. Each stage powers the master clock, the CD transport’s motor and the analogue side of the DAC. In such a configuration, CDi-XR’s internal DAC will be powered by its internal PSU, allowing for cleaner power because it’s fed by a separate PSU to the digital stage. The PSU-XR is also compatible with the Cdt-XR and the soon-to-be-launched Cyrus Streamer.

No matter how talented, an external power supply needs to be partnered with a component capable of producing music, so Cyrus also sent the i9-XR integrated amp. I gather Cyrus feels this to be the combination in which the PSU-XR produces the most significant results. In such combination, two output sections of the PSU-XR are used to feed the preamp section, with another pair feeding the power section in combination with the i9-XR’s internal PSU. The i9-XR’s internal DAC stage is powered by its internal PSU, which is now freed up to deliver a more robust power supply.

Cyrus PSU-XR review

Time for some music

As this was my first acquaintance with the i9-XR in my system, I initially installed it alone to become acclimatised to how it performed. My Totem Forest Signature speakers are not insensitive but do require an amplifier with enough current to control their rather stiff bass/mid driver. I had been a little concerned that, coming after a Moon 600i amp, which delivers both current and power in abundance, the i9-XR might struggle a little. However, I was pleasantly surprised with what I heard in this regard. If you are reading this review and considering purchasing the Cyrus PSU-XR, chances are you are already a fan of how Cyrus amplifiers deliver music. The i9-XR is an extremely fast, lean and dynamic performer.

Dynamics are delivered with both speed and precision. There was less meat on the bones than via my Moon amp, but the bass was present and correct and delivered with a decent amount of weight behind it. Despite the clean sonic balance, there was a pleasant warmth to the sound and a sweet top end. The soundstage was wide and with some depth, but most musicians were positioned within the speakers, with mostly only production effects panning beyond the speaker cabinets. Initially I listened to the i9-XR via its analogue inputs, with a Melco server feeding a Moon 780D external DAC.

Cyrus PSU-XR review

Anticipation got the better of me, and I hooked up the PSU-XR to the i9-XR much sooner than I had planned. I initially listened via the analogue input, still via the Moon DAC. The effect of the Cyrus PSU-XR was not subtle. I cannot think of one aspect of the i9-XR’s musical performance that the PSU-XR did not improve. Most notably, the sound was more detailed and transparent, with performers given greater space around them in the soundstage. I enjoyed a decent sense of weight when the music demanded it, and bass notes filled out considerably. There was now a greater sense of depth and width to the image, with the music finally breaking free from the speaker cabinets. The i9-XR alone produced a clean sound with fast transients, but now the music was cleaner again, adding a little more body to those fast transients.

Listening to Iron Maiden’s Seventh Son Of A Seventh Son (24/44.1 FLAC) I felt I could hear every detail of the mix. Despite the dense production of this album, the music was never congested. The reverb effects on the guitars were laid bare, and Steve Harris’ bass was delivered with greater depth and speed with the PSU-XR in tow. An SACD rip of T.Rex’s Electric Warrior revealed the improvements brought about by the PSU-XR. The sibilance of Marc Bolan’s vocals on the track Jeepster, was now much better resolved, delivering the strong climax to the track with less of an unpleasant edge. The drums now had more drive, and the bongos possessed a stronger sense of rhythm. The amplifier’s dynamics made the crescendo as frightening as the band intended, a relaxing listen it was not and nor was it supposed to be.

Cyrus PSU-XR internal layout

The forward and detailed midrange brought great results with a CD rip of U2’s The Unforgettable Fire album, which suffers from a rather flat and vague production. The Cyrus PSU-XR and i9-XR combo opened up the recording and produced a thoroughly enjoyable rendition. Instruments that can get somewhat lost in the mix with more laid-back sounding equipment were brought to the fore, and rhythms previously buried in the mix sprang to life. The timing qualities of this combination are a highlight. Despite the forward balance, I got through the acid test track, Elvis Presley And America, which contains harsh sibilants and distorted vocals towards its crescendo, without turning down the volume – a rare occurrence.

Switching to the USB input and fed by my Melco server, as before, confirmed the long-held theory that a decent power supply is critical to getting the best out of any DAC. The soundstage opened up and, whilst still not as transparent sounding as my far more expensive Moon DAC, the internal converter proved capable of delivering an enjoyable performance. The timing was much improved, and the upper registers were more refined, losing the slight roughness that I felt was present sans Cyrus PSU-XR. Listening to a Qobuz stream of Kerala Dust’s The Chain allowed the DAC to demonstrate its ability to produce an expansive soundstage and strong dynamics.

Cyrus PSU-XR rear

Cyrus PSU-XR verdict

It is fair to say that the Cyrus PSU-XR transformed the partnering i9-XR amplifier from a good mid-priced performer into a more serious proposition. If you already own an i9-XR amplifier and can afford to purchase the PSU-XR it’s a bit of a no brainer. Owners of other compatible Cyrus XR components should undoubtedly arrange a demo to establish if the benefits are commensurate with the price. Adding the PSU-XR to the i9-XR brings it up to a price point where it will find plenty of talented competition but it can hold its own, especially considering it includes a DAC stage that would cost a considerable amount to better. The amplifiers’ presentation makes listening to music a lot of fun, which is what this hobby should be all about. Music lovers seeking a fast, detailed, dynamic, clean, and refined performance will love the Cyrus PSU-XR and i9-XR combo.


Type: power supply for Cyrus XR components
Connector: 15 pin D-sub
DC output voltages: +5V, ±24V, regulated ±10V to ±45V, unregulated ±45V or ±56V
Size HxWxD: 75 x 215 x 355mm
Weight: 7.7kg
Warranty: 3 years

Price when tested:
Manufacturer Details:

external power supply


Chris Baillie

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