Ultrafide U4PRE/U500DC pre/power amplifiers
The Ultrafide name will be new, but many readers will have unwittingly experienced their pro-audio sister company MC²’s amplification at live events, including Glastonbury Festival’s Pyramid Stage. It is equally possible that one of their processors was used during recording sessions of some of our favourite albums, as this company has an impressive client resume, including the legendary Air Studios.
The brand’s founding brains belong to musicians come engineers Terry Clarke and Alex Cooper, who both have impressive CVs. Alex’s highlights include designing guitar amplifiers for Jimmy Page and Pete Townshend, among others. Terry has designed tape machines for the BBC and a digital delay device for Mark Knopfler.
The amplifiers we are looking at here caught my eye at last year’s UK Audio Show. There, I enjoyed listening to a selection of LPs played on a Linn LP12 turntable, with a large pair of Spendor speakers which were moving a considerable amount of air. I was equally struck by the attractive yet compact casing of these amplifiers. I have had my fair share of large and heavy designs at home recently, so the prospect of reviewing something more manageable was an attractive proposition. It seems that I was not the only one to have been impressed by these amplifiers, hence the three long months between my introduction and receiving these review samples. It turned out that the company is relatively local to my home in Somerset, with their office and manufacturing facility being based in Honiton in Devon.
Ultra compact design
Although they won’t fit side by side on a standard-size rack, these products do leave plenty of space on a standard rack to allow the side placement of, say, a turntable PSU or, in my case, a CAD GC 1.1 ground box. Both units are around 10cm tall and do not run particularly hot, so they make undemanding house guests. The black casing looks attractive and is well put together, although the top casing does ring somewhat when tapped. When I mentioned this to Ultrafide, they assured me that there was damping on the circuit board to isolate it from vibrations. A power switch on the front panel of each component powers it out of standby mode. In the case of the U500DC, it glows green when operating correctly and red if clipping or protection circuitry is active.
The U500DC amplifier has a Class D output stage, although the input stage is Class A. It is fully balanced, so the XLR inputs are not just for show. Unlike many Class D designs, which use off-the-shelf modules, Ultrafide designed their own, which features something they refer to as Ultra Sigma technology. This describes a method in which the switching takes place at extremely high frequencies, reducing high-frequency distortion within the audio band. Ultrafide claims this results in exceptionally low crossover distortion, comparable to that of a Class A amplifier.
Power is rated as 250 Watts into 8 Ohms, doubling to 500W into 4 Ohms. In addition to both balanced and single-ended inputs, two pairs of speaker outputs are provided, which makes things simple if your speakers benefit from bi-wiring. Weighing 15kg, the U500DC is reassuringly solid, but handling it was far from the hernia-inducing experience, which is often the case with amplifiers that offer this much power. This amplifier’s beefy, linear power supply is no doubt responsible for a good proportion of this heft.
Between the input sockets is a toggle switch labelled Timbre, which selects between two output modes. Pure could be considered the default output, with Vintage routing the signal via a Class A/B module. This gives a euphonic colouration, which Ultrafide feel may suit some systems and, indeed, listening tastes. In my setup, to my ears, the Vintage setting restricted the soundstage and lacked leading-edge definition. Hence, the Pure setting was used for the majority of my listening. My system has been tailored towards a more organic and forgiving sound, so this is unsurprising and doubtless the Vintage setting could be a godsend if this amplifier is used in more forward-sounding systems.
The U4PRE preamp operates in Class A and is, again, a fully balanced design. As audiophile designs go, it is well specified, notably offering a configurable MM/MC phono input stage. Those familiar with my review work will know I do not currently have a turntable , still, as mentioned above, I was very impressed when I heard this amplifier fed with a Linn LP12 last year, so the phono stage appears to be more than up to the job. In addition to the phono input, there are an additional four line inputs, two balanced XLR and two via RCA connectors. The U4PRE has twin outputs for both balanced XLR and RCA, which are connected in parallel and remain active at all times, which should make bi-amping a simple affair. Helpfully, a remote trigger output is provided for connecting to the power amp to facilitate single-touch power on/off operation.
Living with the U4PRE was a pleasant experience. The display proved to be legible from across the room. You can dim the display or turn it off completely, although I found it somewhat frustrating that operating a control whilst it was turned off would reactivate it and require me to turn it off again manually. The aluminium remote is a generic type feels solid and works well. The two knobs on the front panel operate volume and input selection. Holding in the volume control mutes the output while doing the same with the input selector selects the balance control. Completing the front panel is a full size 6.3mm headphone jack, which mutes the output to the power amp when in use.
Ultra hi-res performers
Following what has seemed like a revolving door of speakers in my listening room, my Totem Forest Signature speakers were reinstalled a couple of weeks before these amplifiers arrived and were used throughout this review. Townshend F1 Fractal balanced interconnects were used between my Moon 780D DAC and the Ultrafide U4PRE and again to connect this preamp to the U500DC power amplifier, which in turn fed Townshend Isolda cable speaker cables. Titan Audio provided the mains cables; the digital cables used here are from Network Acoustics.
I have enjoyed hosting a good few amplifiers in the last 18 months, and many that retail for a similar price to the Ultrafide U4PRE and U500DC combination. Upon mentioning this to Ultrafide’s representative, he told me that he felt these amplifiers were priced highly competitively and could hold their own against more expensive designs. I was informed that although my samples were brand-new units, the amplifiers had been subjected to rigorous burn-in procedures and should reach optimum performance within a couple of hours. My experience was somewhat different, and I found the pairing took a good few days before they settled down and the music filled out, especially at low-frequencies.
Once run in, this amplifier combo performs at a level well above its price point in certain key areas, such as soundstage, insight and detail retrieval. It delivers a leaner sound than I am used to and it took a few days to accommodate this but there proved to be much to enjoy. Music from this amplifier is lean, lithe and detailed. The top end is sweet, airy and delicate, with softer leading edges than I was expecting from a Class D amplifier. Whilst the soundstage is large in all dimensions, instruments within it are smaller than is the case with some of the big Class A/B amplifiers I have given rack space to recently, particularly the far more expensive Audia Flight FLS 1/4 pre/power combo.
The soundstage reminds me of a finely painted picture; every detail is neatly laid out and accurately described but painted with a fine brush. Dynamic swings are delivered with impact and weight when the music demands, and the bass is firm, tight and deep, although often a little further back in the mix than is the case with amplifiers such as my Moon 600i or, indeed, the Audia Flight FLS1/4. Complex rhythms are well-rendered and easy to follow, although perhaps there is slightly less rhythmic drive than from certain other designs.
It is fair to say that the balance here is on the analytical side, allowing the listener to revel in the sonic beauty of the best recordings, but that smooth top end takes the edge off the worst recordings. The lean balance does result in less instrumental body, and the softness can be at the expense of the finest details; for example, Paul Desmond’s alto saxophone on Dave Brubeck’s Take Five (DSD) sounded dynamic, lively, and airy, but lacked the final degree of shine and rasp and sheer physicality that my Moon amp brings out of this track. Having said that, via the Ultrafide amps, the piano and drums were beautifully crisp and well-defined yet utterly free of fatigue, so it’s hard to say which is the most accurate.
Carole King’s It’s Too Late (Mofi SACD rip) was similarly smooth yet insightful. The distortion to her voice, presumably caused by microphone or input desk overload, was less evident than usual. Yet, I could hear into the recorded acoustic and appreciate every detail of this comparatively ancient recording.
Polyphia’s New Levels, New Devils (24/48 download) always creates a room-filling sound. Here, there was no lack of detail, and this amplifier’s resolution and organisational qualities allowed me to follow each instrument. This is a particularly forward and punchy recording and one where studio compression has been used creatively. It can sound somewhat edgy, but this amplifier smoothed the worst excesses, which meant I found it easy to get carried away with the volume control. The bass was clean, deep and powerful but perhaps slightly restrained and lacking the last degree of drive by comparison to the Moon.
The Ultrafide amplifiers gave me more detail and focus here, but the Moon sounded bigger and bouncier. Equally, I felt that the Moon amp’s presentation had a little more flow and grace, but the Ultrafide told me more about the tonality of the guitars and sounded cleaner and more controlled. Similarly, Rage Against the Machine’s Pistol Grip Pump, from their album Renegades (CD rip) was delivered with more physicality via the Moon amp, but the Ultrafide dug further into the mix, giving superior instrumental separation and notably gave great insight into the characteristics of the guitar pickups.
The U4PRE’s headphone stage proved a real treat, with plenty of power on offer to drive Sendy Peacock planar magnetic headphones. The sound was full-bodied, airy, detailed, rhythmic, and powerful. This headphone stage possesses a lovely, velvety top end and three-dimensional image, which made it hard to return to my usual solution. Repeating Dave Brubeck’s Time Out via headphones sounded even more airy and spacious than via my speaker setup, with excellent timing and instrumental phrasing.
Conclusion
The Ultrafide U4PRE and U500DC amplifiers were as good as I hoped they would be and are a welcome addition to this well-populated market segment. Their compact dimensions make them easy to accommodate and certainly easy on the eye. The U4PRE contains all of the features that I look for in a preamp, and I was particularly impressed with the headphone stage. The U500DC is supremely quiet and is powerful enough to drive almost any real-world speakers.
The clean, lean and detailed sound is very easy on the ear yet dynamic and revealing. The smooth and forgiving balance of this amplifier makes it easy to enjoy the majority of your music collection rather than just those special recordings that sound good on almost any system. And when you do put on a great recording, it makes it a worthwhile experience. It delivers a leaner and more analytical sound than some, but an entertaining one that works with all kinds of music. I can see the Ultrafide U4PRE and U500DC amplifiers winning many fans for build, design and sound quality. This combination could be the one that puts Devon firmly on the map for hi-fi and music lovers, and it certainly deserves an audition.