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Sugden Audio A21SE Integrated Amplifier Review

Chris Redmond tours the Sugden factory and gets an A21SE integrated amplifier for review, too

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Sugden A21SE Integrated Amplifier

The Tour

Saturday, 8th April, England; day of the Aintree Grand National when even the most dour-hearted individuals are often tempted to venture through the door of the local bookmaker to place the almost customary pound on a four legged nag which inevitably deposits it’s jockey unceremoniously on his backside before half a dozen fences have been negotiated.

As it was my own pound sterling would be staying put this year as besides not wishing to jinx any particular runner, I had been invited to the Sugden factory in West Yorkshire to pick up an A21SE integrated amplifier for review. Being a long time admirer of the stalwart Sugden A21a, I’d enquired about reviewing the A21SE a couple of months or so previously, but the fact that Patrick Miller of Sugden had also offered to show me around the factory meant we had to arrange a mutually convenient date. It also transpired that a couple of review samples hadn’t been returned by other reviewers who had kept them as references; great publicity for Sugden (and great for the reviewers) although I’d hazard to guess probably not so great for any similarly priced amplifiers which might be directly compared to the A21SE during their own reviews….but I’m getting ahead of myself.

Back to the National then, and in a surely ill-fated attempt to pay homage to those audio reviewers who are seemingly programmed from birth to make the most tenuous of audio analogies, I’ll boldly suggest that the primary asset a jockey must possess to last the course and get around the gruelling Aintree circuit – twice in the case of the National – is a solid, reliable horse of a proven bloodline, preferably wearing blinkers so the competition (and the cheering crowd) don’t interfere with the horse’s intended path.

Apart from the fact it’s the horse wearing the blinkers rather than the jockey (the amp also has four feet so don’t dismiss the comparison out of hand…) this sums up the success of the Sugden A21 series of amplification through the years which now culminates in the A21SE awaiting review through the factory doors.

That’s me falling at the first fence in the ‘Analogy Stakes’ but back to my appointment. The odd light shower apart, it was a gloriously sunny day, and because I’d arrived outside Sugden’s 20 minutes ahead of schedule after a 40 minute drive, I was able to enjoy a quick cup of tea and an egg & bacon sandwich – paid for in part by the pound I was depriving the bookmakers of, and I speculated that if the A21SE was as tasty as the sandwich, I was in for a treat.

Exactly as arranged, 10:30 and I’m entering the premises of J E Sugden & Co Ltd, an old mill in Heckmondwike where Sugden relocated some twenty years ago from another mill in Cleckheaton which formerly housed James Sugden’s original company “Research Electronics Ltd” until the audio side of the business took off/over, and James was able to indulge his real passion, perhaps, without the financial safety net of designing and manufacturing all manner of scientific instrumentation and measuring equipment.

Incidentally, Patrick’s father, Tony, still uses some of Sugden’s own designed early audio test equipment, such as their millivoltmeter, signal generator and distortion measuring unit to develop new products like the A21SE, just as I’m assuming Jim Sugden did in 1967 to design the original Class A A21 which put Sugden Audio on the map; well, the A21 and Jim’s penchant for provoking debate in the audio press with regular contributions that helped promote both himself and his company to discerning readers and potential customers.

Most of the early debate was of a technical/theoretical nature amongst fellow electronics/audio engineers, but despite being dubbed “the brilliant audio engineer” in audio circles, Jim also encouraged subjective listening to enable both layman and ‘expert’ alike to reach their own conclusions about which was ultimately ‘superior’, class A or class AB, immaterial of whatever objective measurements might suggest.

Tony Miller, Managing Director
(picture copyright

No Jim Sugden at the factory today, however, although he was for a short while employed as a part-time consultant when the present management took over. Instead, I had the current head honcho Patrick Miller to greet me with a handshake and yet another cup of tea once I’d ascended the stairway……..

The initial chit-chat over – which amongst other things, revealed we were the same age and that I was born in the same hospital as his wife – Patrick led me through an assembly area where two young ladies were busy getting some overtime in. All Sugden components are hand built and hand finished to a very high standard with the Masterclass series in particular being highly desirable models of minimalist design allied to solid build.

Stepping back in time a decade or two, we entered Patrick’s father, Tony’s workshop.

After being introduced, I asked Tony about the importance of component quality in his designs as although it’s usually audio engineers who scoff at unqualified amateurs (i.e. – people like me) for suggesting one capacitor might sound different to another despite measuring the same, Patrick had emailed me a couple of attachments during our earlier correspondence, one of which had mentioned how Sugden realised that two identical circuits could sound completely different if using different components. To those of us with experience of modified audio components this isn’t exactly headline news, but it seems to be only the more enlightened designers who consider this aspect and certainly a designer must utilize subjective listening to appreciate the subtle differences which can’t be picked up on a capacitor’s spec sheet – at least not yet.

…Sugden realised that two identical circuits could sound completely different if using different components.

Tony also explained how Sugden take great care in sourcing their components from the point of view of sound quality and where the component will be applied in the circuit, with quality control also a major consideration as it’s vital to have consistency from one batch to another. Responding to an enquiry of mine, Tony described why Toroidal transformers are preferred to E-core in Sugden amplifiers.

Basically it’s down to build quality. During manufacture the thin layers of metal which form the core can overlap and cause a flux to occur which can affect neighbouring components if the transformer isn’t orientated to best negate the effect. Given that the area of flux can vary from transformer to transformer, it’s understandable why toroidals have found favour among SS amplifier designs and I’d also suggest that they lay down quite flat in the chassis and don’t require the same physical headroom in the amplifier’s casing for a similar power output.

Background On A21SE

As explained earlier, Tony has been using the same in-house designed audio test/measuring equipment (extremely user friendly by all accounts) for many a year now – he and his son have been the custodians of the Sugden brand for almost 30 years – and maintaining a constant reference point can only help when it comes to refining and improving circuits. If the same designer is also still on-board it will virtually eradicate any chance of a backward or even sideways step sound wise – think Snell or Musical Fidelity for instance – and Sugden do say they remain faithful to the classic A21 when it comes to mid-band tonal balance and fatigue-free listening.

Besides the current production Class A/B AmpMaster, there are also many earlier, post-A21 Sugden Class A/B amps in existence which were a reluctant concession to the trend for higher power output and inefficient speakers, but in 1987 Sugden revisited and re-evaluated the A21 design after new input from Class-A fanatic Jan De Jong, resulting in the A21a which became a reference at the price then and is still the one to beat even now, in my humble opinion.

Where the A21SE benefits over the original A21 is primarily in increased bandwidth and power output (30wpc as opposed to 10Wpc), although it must be mentioned that the A21SE isn’t simply an upgraded A21, or even the intermediate A21a, for that matter, despite the basic circuit principles (such as a single voltage rail and ‘push-pull’ load sharing output transistors) remaining constant.

In fact, rather than compare the A21SE with the A21, it’s probably as relevant for potential purchasers of the A21SE to thank owners of Sugden’s flagship Masterclass series of pre/power components for much of the newer integrated’s R&D, as many of the advances made during their development trickled down, so to speak, resulting in an amplifier which is now ideally suited to make the most of the advances in CD replay or vinyl for that matter, although unlike the A21a, there is no phono stage option with the A21SE.

Patrick was quick to point out, however, that there are two reasonably priced separate phono stages now available which compliment the A21SE perfectly, one with its own power supply and one powered direct from the amp. In fact, Patrick was quite bemused that these units hadn’t received the attention he felt their quality deserved, but as I couldn’t find any info relating to them on the net, it could just be down to a lack of exposure.

There’s also the RC5 remote control which, although primarily for the matching CD21SE CD player, also adjusts the volume of the A21SE, and just to demonstrate that Sugden do keep an eye on the opposition (not totally blinkered then) and can make the odd concession to the 21st Century so long as sound quality isn’t compromised, the A21SE has a power on indicator which is….drum roll please…….blue, but personally I find bright LEDs a distraction and the Sugden’s is a little too bright for me as I prefer to do my listening with the lights out. This small detail was nothing that a strategically placed piece of tape couldn’t sort out however, but as it transpired I left it alone – it wasn’t that annoying.

Before carrying on I suppose an idiot’s guide to Class A operation is in order, as this is what most enthusiasts immediately associate the Sugden brand with, but there’s heaps of information out there in cyberspace, so do you really need me repeating it here when everything you ever wanted to know is a couple of mouse-clicks away? Very briefly – Class A amps are hotter, less energy efficient and consequently more expensive per watt to buy, but don’t suffer from ‘crossover distortion’ (where signal is split into positive and negative phases then reassembled), hence the sound is universally regarded to be purer than Class A/B.

That’s the over-simplified abridged idiot’s guide, now go ‘Google’.

What I should add is that Class A operation in itself will not equate to ‘better’ sound just as a valve amp is
not guaranteed to sound any better than your average Class A/B either. It’s all to do with the implementation, but Class A does allow a simpler circuit to be designed which can only be good when it comes to retaining the integrity of the original audio signal. With the audio signal, less components in the path and less interference is almost always better in my experience.

In addition, I’ll also add that although most reviewers inevitably compare the presentation of Sugden Class A amps to that of valve amps, it’s imperative that you understand we’re not really talking of a euphonic colouration here as the sound is neither lush nor over warm. Instead, it is gloriously natural and liquid with no smearing of detail or rolling off of high frequencies.

It’s probably more helpful to imagine that no amplifier and, indeed, no component can be 100% transparent, and therefore they must detract from what was put on a recording to some degree. I’d speculate that Class A tends to detract from recordings less than other more energy efficient designs, and hence tends to sound more convincing and consequently more involving (with vocals in particular), although of course hard line objectivists might disagree. Basically I’d say it isn’t Class A adding unnatural warmth, rather it’s Class A/B losing natural warmth, again with the proviso that the design and the realisation of the design are up to par.

Sugden were the first company to manufacture and market a Class A, transistorised amp in the UK and they’ve spent the last 30 years or so refining their own unique tried and tested circuitry, learning exactly what characteristics they need in discreet components to best suit where they’re used: basically, no one has a better pedigree when it comes to applying Class A to a SS circuit than Sugden Audio, and the fact that Sugden house their circuits in such superbly built shells is the icing on the case.

As Patrick showed me the ground level engineering department containing numerous milling, forming and finishing machines, he explained how Sugden buy in one ton of extruded aluminium from Germany at a time to work with. Well, with the faceplate of the A21SE being 10mm thick and Class A requiring such meaty heat sinks, you don’t want to be running out during a production run, especially when there are currently orders from the Ukraine, Russia, Holland, Germany, Hong Kong and the USA, among others to fill.

Grand tour over, we both retired to the listening room used to assess whether Tony’s chin-scratching and hours of labour with the soldering iron were producing fruit or not (no lemons allowed obviously).

Despite being modest in size, the room had carpeted walls and a cork lined floor which prevented it from being too lively; in fact, Patrick confirmed that some thought it sucked the life out of the music somewhat although neither of us thought this was a problem, and after cueing up a nice piece of jazz on the CDP followed by a virtuoso pianist, it was time to pick up the review A21SE and head for home, or rather it was time for Patrick to pick up the A21SE, as Sugden’s insurers had advised that a layperson like myself could fall, get injured and make a claim against them, so while in the Sugden factory I had the manager as my own personal baggage carrier.

Many thanks to Patrick then for a very informative and interesting experience – I only wish I’d been able to stay longer and listen to their other components through the multitude of speakers they keep for reference, such as the Quad 57s which sat alongside the French multi-driver units which were used during my brief stay.

At Home…

That’s an abbreviated account of my visit to the Sugden factory and an even more abbreviated trip through Sugden’s history completed, but I’m guessing the main reason you’ve clicked onto this review is because your main interest will be in how the A21SE actually performs, and in this respect I can inform you I wouldn’t have just wasted my time writing over two thousand words about a company and their product if they’d handed me a component to review which was a merely competent, run of the mill also ran.

No, I’ve put the hours in – it’s even affected my sex-life for goodness’ sake – because the A21SE is such a superb piece of equipment, and it’s the chance to hear this level of quality in my own system and share my experiences with others which tempted me to join the Dagogo team in the first place.

Sat here listening to the same old CDs, I inevitably find myself pulling out the rack for reference purposes. This ‘job’ doesn’t seem too bad at all as I now recognise I was becoming ever so slightly jaded with audio before making the acquaintance of the Audio Note AN-E SPE/HE speakers I reviewed previously, which at 98dB sensitivity, have proved a marriage made in Heaven for the A21SE.

Bearing in mind that the AN-Es gave a remarkable demonstration of deep, agile bass whilst connected to 8 watts of Meishu SET valve amplification at the Manchester Hi-Fi Show, it’s no great surprise that 30 watts of SS Class A results in all the grip and drive that anyone could sanely wish for, but of course it’s that magical midrange which Sugden and Class A in general are renowned for, and here the A21SE delivers big time.

High-hats have that highly resolved quality which lets you know the brush is a brush with many individual strands and not a piece of sandpaper. Yes, I’m reluctantly having to revert to the usual reviewer-speak now, but with any component which could be described as being seductive and yes, ‘musical’, it’s important to get it across if that component is also highly resolving, otherwise the previously mentioned suspicion of euphonic colouration crops up.

As it is, the A21SE crosses all the T’s and dots all the I’s when it comes to even the most demanding audiophile’s checklist at or anywhere near the price, and all in a beautifully hand finished, superbly engineered chassis which looks like it could stand more abuse than an aircraft’s black box flight recorder.

Yes, with the AN-Es the music is effortless, supremely natural and ‘high-end’ in the best sense – like high-end should be, in fact, rather than the anodyne, clinical, over analytical presentation that seems to rear it’s yawn-inducing head when a certain price point is reached, but not everyone has 98dB speakers, so how would the A21SE deal with the Revel F30s at 87dB?

[I did originally write “…the Revel F30s at a more typical 87dB”, but in retrospect the Revels are perhaps some of the least efficient speakers in domestic use, and 89dB/90dB is going to be nearer the mark. Whichever it is, if the Sugden can drive the F30s to an acceptable level whilst remaining in control, you can be confident it will drive the vast majority of speakers out there and doesn’t need to be confined to high efficiency designs.]

There’s a saying that you should do one thing every day that scares you, so with this in mind I took a deep breath and hoisted the first Revel F30 off the ground before negotiating the thirteen stone steps and ninety degree bend which lead downstairs. After much grunting and cursing, the AN/Es and stand were taken up the stairs, and listening commenced with “The World of Drums and Percussion” on CMP records (CMP CD 5004) which would be a real test of the A21SE’s driving abilities – and a test of my tolerance of a CD with apparently no musical merit whatsoever……but wait a minute!

First impressions confirmed that besides the fact I really did prefer the AN/Es for definite now, this motley collection of drum-thumping, skin/wood/tin/kitchen sink whacking tracks was proving to be a quite enjoyable experience as the A21SE – besides showing that it could indeed rattle the living room window when asked – demonstrated just how much skill and subtlety a percussionist can possess, and just how much individual character there is between their plethora of ‘instruments’.

Not that I’d recommend you to hunt high and low for this CD, you understand – I bought it some years ago because it was in a sale – but for some strange reason I know I’ll end up listening to it again this week which is quite disturbing…….

So then, after hoping that the Sugden could at least drive the F30s to an adequate level, I was pleasantly surprised at the trouser flapping capabilities on show, and while we’re not talking of the speakers being kept in the ‘vice like grip’ of a mega-watted Krell, neither are we are talking of bass drivers sounding like bullfrogs farting under water and a Krell wouldn’t have the ‘vice like grip’ on my attention that the Sugden had.

The long and the short of it is that the A21SE does drive the F30s and provides quality, resolved bass at realistic (and slightly above) listening levels, but if you want PA levels for parties, it would be disrespectful to inflict such duties on the Sugden. You wouldn’t have a thoroughbred pulling a plough now, would you? Has the equine analogy grown on you yet or am I flogging a dead horse?

Again, as with the AN/Es, vocals had that certain intimacy and fluid, natural quality which Class A excels in, and after the drum thumping disc was placed back in it’s case, I spent the next few hours listening to jazz, folk, country, and various MTV unplugged recordings which revealed the differing acoustics and venues beautifully.

At Closing…

That about wraps up my second review, you’ll be relieved to know, just as a hernia inducing parcel arrives from Audio Note containing a beautiful pair of Quest Silver SET amps which I’m assuming will be a perfect match for the wonderful M3 preamp now sitting idle. Combined price of these AN pre/powers is, I’d guess around £7,000 to £8,000 UK pound sterling (total U.S. MSRP $12,950. –Ed), so however tempting it is to wait and make a direct comparison with the £2,000 A21SE integrated, I’ll pass.

As it is, the A21SE has exceeeded the already high expectations I had for it, after being extremely impressed by it’s sibling A21a in a couple of acquaintances’ systems and at various shows, and I’m very happy to be in the position of now having reviewed two products which have been revelations in the music making stakes. Granted I’ve been able to cherry pick what I’ve reviewed so far, which means it isn’t exactly surprising both reviews are enthusiastic endorsements, but there is always the risk that individual components from companies I regard as singing from the same hymn sheet as myself might be incompatible with my system/room, and if this were the case, I’d have to reluctantly pass my experiences on to the reader.

Fortunately both the AN/Es and the A21SE were instantly able to make themselves at home and showcase their respective talents which are considerable.

In conclusion, the A21SE is the most musical, involving SS amplifier I’ve yet to hear and at £2,000, it would get my BEST BUY and RECOMMENDED awards. I’d also implore anyone with reservations about the 30 watts output to demo the amp in their own system or with speakers of a similar sensitivity to their own – I think they’d probably have their preconceptions quashed, and don’t forget the bass you get from the A21SE is all finest Class A with no biasing into AB to muddy the water and bolster the output rating.

I’ll be sorry to return the A21SE.

Also read Chris Redmond’s review of:
Audio Note AN-E SPe HE

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2 Responses to Sugden Audio A21SE Integrated Amplifier Review

  1. Clement Ng says:

    Had an a21a for many years of superb listening pleasure before it gave up the ghost due to heat exhaustion. Highly recommended giant killer.

  2. Colin McWilliams says:

    I am hoping to audition the A21 SE signature, with my Spendor D7s, and compare it to the ANV 50, which sounds like it ‘s a different proposition being A/B output?, you didn’t happen to hear it on your visit to the factory?

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