Almarro A50125A Power Amplifier (Hi-Fi+)

Tubed power amplifiers
Almarro Products A50125A Power Amplifier
Almarro A50125A Power Amplifier (Hi-Fi+)

The recent explosion of audio products manufactured in China seems to have included a high proportion of valve based equipment; in itself no mystery if one considers the amount of hardware involved in an average tube design when compared to its solid state equivalent. The necessity for output transformers, chokes and bulky components rated for high voltage and elevated temperatures around valve bases veers off in the opposite direction to miniaturised, mass produced surface mount technology and robotic construction, but the utilisation of cheap labour suits old fashioned construction methods rather well. Well enough to be able to produce equipment that even after the costs of shipping and import duty to Western shores, allows a selling price that as one ex-UK based amplifier manufacturer put it “has completely shafted the idea of manufacturing valve amps in the UK”.

While a lot of the indigenous Chinese valve amps do not stray very far from the path of predictable and rather unimaginative design, there are a number of companies that have been quick off the mark in combining the low cost material and production skills of the far east with design carried out closer to home with interesting results. But while there are plenty of integrated designs and power amplifiers to choose from, they tend to be single-ended or single pair push-pull designs of limited power. What is missing from my personal radar is product with the more usable output of a hundred watts or so. Sure, there are highly desirable – and expensive – examples from Audio Research, Conrad Johnson and the like, but there seems to be a shortage of more adventurous designs at an affordable price. It might have been no more than coincidence, but shortly after lamenting this fact with RG, the Almarro arrived on my doorstep. The somewhat awkwardly designated A50125A would seem to fit the bill almost perfectly, a chunky 125-watt per channel stereo power amp for considerably less than three grand, although ironically it doesn’t come from China, but Japan. With no prior knowledge of the company or the design, I had no preconceptions regarding the Almarro’s sound, but within a very short space of time it was clear that it was going to appeal to me. Driving the little B&W 805s and fed from the Audio Research SP10, there was an immediate and palpable sense of excitement; the Almarro has a body and drive that readily kicks into gear, endowing music with life and a sense of purpose. I will admit to a sense of déjà vu with this particular combination, as the Almarro reminded me very much of the Audio Research D115, an amplifier that seemed to have boundless energy, or to put it crudely, a real sense of balls when the occasion demanded. That it was often partnered at the time with small Sonus Faber loudspeakers was no coincidence; it was a similar synergy that I was hearing with the Almarro and the 805s.

With the arrival of the big Spendor SP100 loudspeakers the A50125’s abilities at the bottom end were thrown into focus, and it proved an illuminating combination. The extra bandwidth revealed more of the enthusiastic drive that the amplifier was capable of, and although it did not reach down to sub-type frequencies, nor possess the ultimate grip and control that some really good solid-state amps are particularly good at, there was a degree of camouflage that in practice, meant you rarely noticed it. Upon hearing his loudspeakers in the system, Philip Swift, the MD of Spendor (and previously responsible for Audiolab – about as solid state as you can get) was heard to comment “I don’t generally like valve amplifiers” but I am fairly sure he thoroughly enjoyed himself listening to music for that afternoon! While admittedly the Spendor is an easy load, the Almarro had no problems in generating really quite antisocial levels without losing control and more importantly, maintaining that infectious sense of kick that makes it genuinely fun to turn the volume up occasionally – an occupation I thought I’d grown out of.

Almarro is an offshoot of a small, family run business that for thirty years has specialised in the design and production of OEM electronics for the communications industry; they have been quietly making amplifiers and loudspeakers since 1999. In a way it seemed inevitable when one looks at the scenario. Head of the company is Yoshihiro Muramatsu, a selfconfessed music lover and audiophile who is not averse to building truly scary amplifiers using enormous industrial Russian transmitting tubes. Combine that with long experience of sourcing electronic components and the constructional expertise gained from his commercial enterprise and the results begin to look interesting, particularly as Muramatsu-san has some refreshingly down to earth views when it comes to high-end hi-fi. He has a preference for well-specified, easily available components from large companies as opposed to ‘audiophile’ grade types, where he considers consistency and quality control to be an issue. Similarly there is a refreshing lack of ‘glitz’ or additional cosmetics to flatter the basic construction; what you see is what you get.

A similar approach applies to the circuit design; while there’s nothing in the Almarro that we haven’t seen before (bear in mind that the comparative simplicity of valve circuitry and hundred year history sees to that) there are enough unusual features to elevate it from the run-ofthe- mill, and the signature of a designer who has a real understanding of and empathy with valve engineering. Take, for example, the driver valve – with the exception of some more contemporary American products, most designers would have opted to use something along the lines of a ECC82 or ’88, and on paper it would seem to have ample characteristics for the job, certainly for driving a couple of output valves and in theory, multiple pairs. In practice, I have never been convinced. I think that transient demands are not accurately reflected by data sheets and anything over 50 Watts or so requires a different approach. To this end, the Almarro uses an American 5687 valve to do the job, a tube originally developed for use in televisions and rated at three or four times the dissipation of an ECC88 whilst possessing a particularly high peak current capability (pulse current) which marks it down as ideally suitable for a driver stage. Not surprising then that we also find it used in the Kondo Ongaku and Gakuoh and the sadly now departed MFA 120 and 200s.

The output stage is based around a quartet of 6550s a side, running (I’m fairly sure) in straight pentode mode rather than the more conventional ultra linear configuration, while the cathodes of these valves are coupled via the secondary of the output transformer in a fashion favoured by Audio Research until relatively recently. Like most valve amplifiers of this sort of power the Almarro uses fixed bias to set the operating conditions for the output stage; measurement points and adjustment are conveniently located on the top plate avoiding the necessity to delve inside, although the use of a digital voltmeter is required. I would hazard a guess by the amount of heat generated that at the set-point the amplifier is working in class A for the first twenty Watts or so before running toward AB1.

While relatively compact for its power output the Almarro is pretty heavy, and the long thin chassis makes placement a little difficult when it comes to conventional racks and supports. The large enclosure at the rear houses the two output transformers and a smoothing choke. Extending in front of this, between the two rows of output valves, a smaller box hides the slim but substantial C - core mains transformer. Over this sits an arrangement of metal strips that are not close enough together to offer any real protection to the valves (or prying fingers) but do serve to lend an interesting architectural air to the amp’s aesthetics. Connections at the rear are pretty much standard with single-ended RCA inputs and five-way loudspeaker outputs offering matching to 4, 8 and 16 Ohms, while a small switch defeats the internal fan (which is not obtrusively loud) but this should probably be left on where possible. Internally the construction avoids circuit boards in favour of tag strips and hard wiring, and while the amplifier circuit is relatively simple the sheer amount of components reveals the considerable attention that has been paid to the power supply and general housekeeping.

Having created a favourable impression, the Almarro stayed in my system for quite some time, allowing plenty of opportunity to play with partnering equipment. The combination of the Almarro with the SP10 pre-amp was thoroughly engaging and highly musical, but substituting the new LS17 provided both a greater degree of detail and a much cleaner presentation, particularly at high frequencies. As I have already suggested, the bottom end is not the deepest or most taught, but is conveyed in such a positive fashion that it does a good job of laying the foundations for everything else. It has a good sense of rhythm and timing that works well with rock music, while the larger instruments of the orchestra have a reassuring sense of body with a mild hint of ‘fruitiness’ that swamps a little of the texture. The mid is again quite full, and although I would be reticent to label it with the typical ‘valve’ character it is both liquid and informative, with just an occasional tendency to lose its grounding with the bottom end. The top end has a degree of ‘presence’ giving a good sense of detail, albeit with a slightly fuzzy quality that reads on paper far worse than it sounds; and while it doesn’t give the impression of tremendous extension, it’s nicely in proportion to the rest of the spectrum. Worth noting however, is that the Almarro responds well to the addition of some form of mechanical isolation, whether through feet or specialist support. The result is a sound that is altogether cleaner with less grain and smear at the top end. In terms of soundstage, and some further interesting evaluation with the Quad 2805, the Almarro effortlessly projects away from the loudspeakers, and is capable of a solid, palpable image which is certainly three dimensional, but indistinct and lacking focus when it comes to the detail within it. In all other areas, the Quads positively wriggled with delight being driven by the Almarro, the attributes of each unit complementing and balancing each other well, only slightly bettered by the Audio Research Ref 110 at more than three times the price, and even then it might well be a matter of personal taste.

At the end of the day, I don’t think that there is any question that the Almarro is good value for money, and the minor criticisms I have would not deter me in an amplifier that was far more expensive. With enough power to drive a wide range of loudspeakers, it manages to present a coherent envelope that enfolds the music and delivers it to great effect, together with a genuine sense of enthusiasm that is particularly appealing. And if there is a small trade off between resolution and ‘cleanliness’ over sheer enjoyable musicality, it is one that I will happily accept. Particularly as I have a sneaking suspicion that the substitution of the supplied Electro Harmonix valves with something along the lines of the rarefied EAT KT88’s might provide the ingredients to elevate performance in exactly the right areas; given half a chance I’ll be doing it, so watch this space.

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