According to Mr. Tomasz Niedziółka, from the company Audio Consulting, which is the distributor of the A30, this amplifier is a construction made by Guy Sergant from Pure Sound www.puresound.info in England and is manufactured in China. This is why, as usual in such a case, its Chinese counterpart can be seen, named Bewitch (and this is also the name we will find on the box, and not Pure Sound), which, according to the designer himself, does not differ from his creation in terms of manufacturing quality and elements used, what implies also the same sonic qualities.
Manufacturing in China was not meant to imply lowering of manufacturing costs per se. Actually it was more the other way round: first there was an idea to make an inexpensive amplifier working in class A. As we know class A implies quite some requirements on a manufacturer, for example regarding the output transistors, which need to be of higher class, than those used in AB class designs, as well as power supply – the tubes have full bias current flowing through them all the time. This made the choice of China obvious. To make the price even more affordable, Sergant found a company manufacturing nice amplifiers, of good manufacturing quality, and modified the amplifier A30 offered by that company. The first test of the A30 under the name Pure Sound in an European magazine – „Hi-Fi Plus” was conducted with and already modified amplifier, with new elements, new circuitry, but still carrying the name “Bewitch” on the front panel. However this did not discourage the author of that article, Alan Sircom, who is now the editor in chief of that magazine, from appreciating the quality of the sound and giving it the Product of the Year 2006 Hi-Fi+ award.

And this is probably the way to make the best of low- and medium budget audio. At least when you live in the UK… The A30 is a solid amplifier, with tubes working in class A, and the output stage in push-pull based on the 6550EH Electro-Harmonix tubes, very nice tubes, and the input utilizing octal tubes from Chinese make. The rectifier is also using Chinese tubes – one per channel. We have also the best possible elements inside – there we have precise carbon resistors, polypropylene SRC capacitors (French) and an Alps potentiometer (Japan). There is a lot to look at. Another element pulling our attention to the A30 is the ability to switch the output stage from ultralinear (UL) configuration, where the 6550 tetrodes work just like they have been designed, with all grids used, to a triode mode (T), where one of the grids is switched to ground. This mode offers a softer, more linear sound. But this comes at a price: the output power lowers from 30 to 18W, as well as the output damping, what is related to the higher impedance of the output stage. This means, that the loudspeakers need to have high efficiency and high, even impedance. Otherwise the amplifier will be clipping, and/or its timbre will depend much on the impedance curve of the loudspeakers (what will make it fairly unforeseeable).

SOUND
Discs used for testing:

• Criss Connor, Free Spirit, Atlantic/Universal Music Japan, WPCR-25171, CD.
• Danielsson/Dell/Landgren, Salzau Music On the Water, Act Music+Vision, ACT 9445-2, CD; review HERE.
• Kazumi Watanabe, Jazz Impression, east west, EWSA-1063, SACD/CD.
• Kings of Leon, Only By the Night, RCA/BMJ Japan, BVCP-40058, CD.
• Marilyn Moore, Moody Marilyn Moore , Bethlehem/JVC, VICJ-61467, K2HD.
• Michael Jackson, Thriller. 25th Anniversary, Epic/Sony Music Japan, EICP-963-4, CD+DVD.
• Sonny Rollins, Way Out West, Contemporary/JVC, VICJ-60088, XRCD.
• The Beatles, 09.09.09 Sampler, Apple/EMI Music, 84414 2 5, 2 x CD; review HERE.

Japanese versions of the CDs available at CD Japan

For a long time, I was not sure how to begin this test. I would like to be well understood, and among audiophile mythologies, premonitions, “wisdom” and “certainties”, which are probably a part of every hobby, yet in audio those are very strong, that it is difficult to find our way through them, not even trying to fight any of them. I was thing about the beginning, because it is easiest to describe the A30 stating, that it does nothing wrong, it sounds in safe, well balanced way. My concern is, that albeit both characteristics are valued in a positive way, yet in the audio context they might seem “suspicious”. Because a device should be “unbelievable”, turn everything upside down, place the competition far behind it and have listeners get a heart attack from what it can do. At least in audio. And in reality something like this happens once in a Russian year. Yes, I witnessed something like that a few times, but those were really very expensive products, and I encountered only few such products during my life. This is the reason, that when I write about a product, that it just “performs like it should”, then I mean exactly that, and I am not hiding anything underneath.
Interesting for me was the fact, that the sound character repeated, almost ideally, the impressions I had when listening to class A amplifiers from such big players like Accuphase (E-550) and Luxman (L-550 II). A common belief about class A amplifiers is, that they sound warm. And sometimes it is true. But that has to be a conscious choice of the designer, and we can find it more often among solid state devices (except for those I already mentioned, but also the A-65 Accu and the M-800A Luxman should be excluded) than among tube ones. A warm, nice, not fatiguing sound is much easier to achieve in class A, than in other classes. And many times this is fantastic sound. But we have also to add, that in such case, it is at the same time little realistic. This is why class A, a well implemented class A, sounds completely different. Yes, there is some warmth, but this does not come from rounding off, or pushing out the midrange, but from supplying the sound in a clean way, from not depriving it from harmonics, which are reproduced in phase with the basic sounds. And this results in a warm sound, but this is natural warmth, and not an artificial one. Such amplifiers are also more linear than most AB class ones. And that means, that there is no “wow” effect, when we start to listen to them. And the A30 (A=class, 30=power in ultralinear setting) is just like that. Anticipating the facts a little, I will just say, that the sound should be like that, in my opinion, sound we strive to get. This is a good direction, because while still inexpensive, this amplifier allows to built a system around it, not masking the flaws of each stage, but amplifying their assets. This may seem not to be a big change, but in effect, it gives a completely new quality.

Comparing the sound of the A30 to my home system, we can easily reach the conclusion, that the gravity point of the timbre of that amplifier is placed a bit higher – similar to the L-550 II from Luxman, which I mentioned before. So the elements from the midrange, and its upper part, sound stronger. This results in a fresh, quite – for a tube of that kind – open sound, similar, to some extent, to what I heard from the Fountek Altitute 3500. Those are completely different constructions, and in absolute terms the sound from Pure Sound is just better, but here and there we deal with a similar situation. As it seems, the A30 amplifier does not reach very deep on bass, and the lowest sounds are more suggested, than fully reproduced. This is not really a blame, because the devices from that price level just sound like that. Until the very end of its reach, the bass is dynamic and quick.

It has some traces of warmth, but only in triode mode. In ultralinear mode bass is better controlled, it has more differentiated timbre, but some of the velvety midrange disappears. So you need to listen for yourself, to ascertain, which of the modes suits us better. Surprisingly, for me the UL was better. We get a more resolved sound, where there is no such pleasant smudging, which is there in the triode mode, filling all the space with a kind of “film”, but which is – and I repeat: for me – more natural and neutral. The sound in tetrode mode was dynamic and open, something that was lacking in triode mode. Such amplifier is just “even”, but has one more asset – well kept rhythm. And although the device will not surprise us with outstanding resolution, or incredible timbre (and by all means, I am not saying that it is bad), but we will not fall asleep while listening to it. Dynamic, based on a large big band sound of the disc Free Spirits with Chris Connor as the vocalist, was reproduced really well. The amplifier powered my Dobermann Harpia Acoustics with ease, and only the mentioned lack of lower bass showed, that this is not a very powerful amplifier. With stronger sounds from the discs Thriller Michael Jackson and Only By The Night Kings of Leon it was repeated, confirming good dynamics of the unit, and significant current reserves. Dynamic entries of snare drums and kettle drums from the Avatar soundtrack, or the incredibly demanding vocalizes from the disc Scherzi Musicali with Claudio Monteverdi, performed by La Veneziana were held almost until the very end – there, where most solid state amplifiers give up and plays only a not identified pulp, chewed and digested. There the A30 sounded clean and nice, compressing dynamics a little, in the end it is only 30W, but without larger consequences related to the musical experience.

The timbre of the A30 is well balanced. Like I mentioned, in general the gravity point is placed a bit to the top, but not to an extent, that would mean brightening of the sound. To make it clear – this is still a tube amplifier, with a characteristic warm tarnish, generated usually by big, low power triodes and power supply, but disciplined here by the speed and dynamics of the 6550C triodes. This was nicely shown by the Kazumi Watanabe discs, where we mostly only have the guitar amplifier of the leader and the Hiruyoki Noritake bass. This is a contemporary recording, with microphones quite close to the instruments in a dry room, with the reverb superimposed on that, with a full frequency spectrum, here slightly “boosted” on the lower midrange. Although the Pure Sound did not get into the subtleties of showing the ideal position of both instruments, but I did also not expect that – this is the domain of much more expensive devices. But important was, that the lesser way of handling bass than in my system, did not influence the way, the midrange was shown – the Watanabe guitar was warm, close and intimate. And the cymbals had still a very good opening, they were strong and dynamic. They will not be very saturated, or resolved. But we have to remember the price we have to pay for the A30. But this should not disturb much, especially when we will play sound from a source with a full, analog sound, or just a turntable.

And we can continue like that for a long time – we will not catch this amplifier on something bad, we will not hear anything wrong, anything, that would not be worth its price. This is a very even, quite anticipative sound. The amplifier will drive most of the loudspeakers for that money, and more expensive ones, especially in ultralinear mode, and will not show signs of tiring. Maybe this is not a device for “chasers” and beginners, but in audio we deal with a very broad area of needs and expectances. When we find a nice source and even loudspeakers, then it will be fine. Like I said – the A30 will not surprise us with any trick, it will just sound like it should. This is the one thing, I value very high, because while it does not supply us with high adrenaline, it gives us a support in reality, and gives us an orientation in the real world. I recommend it with clean heart.

DESCRIPTION

Pure Sound A30 is a tube integrated amplifier, made in China for a British company. On the outside it looks like a classic integrated, with the tubes exposed on the top and the transformer cups in the back. But there are some elements that make it stand out from the crowd. One of those is the usage of octal tubes in the input stage and power supply – the 6N9P and 6N8P respectively – tubes with big distances between elements, with a characteristic base, here made from metal. A not so common feature is tube rectification, especially at the given price level. In the A30 voltages are rectified separately for the right and left channel – both rectifiers are the 5Z3P tubes of Chinese make (the mentioned triodes come also from China). It is not fully dual-mono, as there is only one mains transformer, but visibly it has to have separate secondary windings for each channel. The front panel is also very nice – finally we have a product from the country of the Great Wall, that has nicely looking knobs, silver, satin, completely not associated with this country. The whole chassis is black, this is why those knobs really look fine. Let’s just mention, that those were mounted on a thick aluminum plate, where there is also a blue LED lit when power is on. There are three knobs – one is the power switch, the middle one controls the volume and the right one selects the inputs. We have only three inputs, and there is no preamplifier or tape output (that could be used for a headphone amp). So on the back plate we have three pairs of RCA inputs and stereophonic loudspeaker terminals – separately for 4 and 8Ω – with nice, gold plated sockets, as used by other manufacturers (like Rotel, Audiomatus, Canor).

The complete circuit is mounted on one, solid PCB. From the inputs the signal goes, by long interconnects, to a very good mechanical selector, placed near the front panel, and then to a “Blue Velvet” Alps potentiometer, and then to the PCB, to the input tubes. The potentiometer has no motor, thus there is no remote control. The passive elements are very nice – those are high power carbon resistors, polypropylene SRC capacitors coupling the individual stages, etc. The tube sockets are soldered into the PCB, and they are nice themselves – they have a ceramic body with gold plated connectors. We see also a large choke. Because there are two rectifier tubes, there is probably a third power supply. As it seems, the tubes are working only for one of the stages, I guess, that this is the current stage. The input tubes have better filtered voltage, by means of the mentioned choke, and rectification there is handled by common solid state diodes. The output transformers and the mains transformer are of the classic EI type. The power transformer has separate windings for both channels, for preamplifier and for the control stage. There is also a separate winding for heating the output tubes and the input tubes. The whole looks really nice and sturdy.

Let me just add, that the British company Border Patrol offers an upgrade for the A30, which places the power supply in a separate chassis. The rectifier tubes disappear from the main unit and are transferred to the power supply enclosure. A test of such a set can be found HERE.

Technical data (according to manufacturer):
Output power: UL - 2 x 30W, T – 2 x 18W (8Ω)
Output terminals: 4 & 8Ω
Damping factor: UL=7, T=5.7 (8Ω)
Frequency response: 13Hz – 60kHz (-1dB)
THD: 0.1%
S/N: 89dB
Input impedance: 100kΩ
Input sensitivity: 500mV (for full power)
Dimensions (WxDxH): 435 x 350 x 200mm