Leema Tucana Vs Stello Ai500

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Leema Tucana Vs Stello Ai500
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From Hi-Fi World - November 2009 issue


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Poles Apart


One comes from South Korea, the other from North Wales, so April Music’s Stello Ai500 and Leema Acousticss Tucana ll couldn’t be culturally more dissimilar, but these two ‘super integrateds’ prove to have fascinating parallels, Tony Bolton finds...


Ah, the ‘super integrated’ amplifier! It’s a concept that’s newer than some might think. In the old days, as recently as the nineteen seventies, if you were to drop the equivalent of £3,500 in today’s money on an amplifier, the chances are it would come in two boxes (or more), rather than just in one. The integrated amplifier was always the poor relation of the pre-power, and never as sexy. But by the mid-eighties, companies such as Naim, Exposure and NVA were making premium priced one box designs, claimed to offer all the allure of your old twin boxer in half the space.

These days, the average chunk of change expended on an integrated amplifier is rarely more than £1,500 (if Hi-Fi World’s letters pages are to be believed), but still manufacturers keep coming back with lavishly priced, expensively built one boxers. Just like household utility bills, no matter how much you ignore them, they just don’t go away!

In the UK, Leema Acoustics has made a name for itself largely off the back of the Tucana, which was an excellent integrated that’s neatly filled a niche in this country. A kind of hi-fi ‘one stop shop’, it had power, facilities and polish in equal measure, and now it’s just been replaced by the new mark II version, more of which in a moment...

Some ten thousand miles or more away, a company called April Music has been making high quality, affordably priced audiophile gear for over a decade now. We’ve dipped in and out of the April Music portfolio over the years, and never failed to be impressed. Designed and built in Seoul, South Korea, they’re a tantalising taste of what we used to call 'Japanese high end', inasmuch as they share the same values. Build quality is superlative, and the sound isn’t so dissimilar. You could even say the Stello brand is almost the Far Eastern equivalent of Leema...

As such, we thought we’d put the two tribes up against one another, and appropriately enough, bring in Hi-Fi World’s stalwart reference, the Sugden IA4. Normally resident in DP’s system, he grudgingly delivered it to my door for the purposes of putting these two new pretenders to its throne through their paces. It’s a striking sounding bit of kit, its full Class A circuitry doing things that rivals simply can’t. To my ears it’s not all good though, but for shining an unflattering light on price rivals it is surely superb.

Moving to the Britisher first, and the new Leema Acoustics Tucana II maintains the swish, stylised looks of the original, but adds a flourish on the front panel. Opinion’s divided on the styling; DP wasn’t so keen on it compared to the old model, but I like the new ‘un. The volume control remains on the left surrounded by blue LEDs, but the source selection is now by button rather than knob, on the right hand side, and in the centre are a row of four more buttons for gain, balance, mute and the tape loop. Located on the far left are mini-jack sockets for MP3 input and headphones output.


At the back are the relevant sockets for balanced input (XLR) and rows of gold plated phono sockets for the six analogue line level inputs and the tape loop. Speaker binding posts are at each end of the back panel, and mains input is in the centre. The casework measures 440x110x320mm, weighs in at 18kg and is available in either black, or the silver finish on the review sample.

Mallory Nicholls, co-founder of Leema, informed me that in the preamp section the circuitry remained the same as that in the original Tucana but the software functions had been taken from the Pyxis preamp, which forms part of Leema’s Reference range (the Tucana coming from the middle ranking Constellation series).

The power amp section features new Thermal Tracking Output Devices which feature five pins instead of the three normally found on transistors. These extra two pins feed a close coupled thermal tracking element which measures, and reacts to, the temperature of the device in real time. This enables the amp to be configured with a lower output impedance which improves bottom end control, Leema says. Power for all of this comes from three large toroidal transformers, one for each channel and one for the preamp.

Hailing from South Korea, April Music are now in their eleventh year. The Stello Ai500 is the company’s new flagship product. The gentle curves of the sides of the amplifier disguise its substantial 460x86x400mm footprint. It is a very deep unit and with access for the cabling may be a tight fit on some racks. It weighs 16kg. The fascia is populated by a red display, which shows the source selected and the current volume level (on a scale of 0 to 99). set by a Cirrus Logic CS3310 digital volume control, actioned by a large knob on the right hand side. Running across the centre are push buttons for source selection for the four unbalanced and one balanced connection, as well as the four digital inputs to the DAC. These comprise S/PDIF, coaxial, USB and iPod USB.

All the appropriate sockets are on the back panel along with the mains input and speaker terminals. Internally, there are separate power supplies for the preamp and DAC circuits, while juice for the power amplifier comes from a 800VA toroidal transformer and a 90,000 microFarad capacitor bank. The output stage employs matched Hitachi MOSFET power transistors. The casework seems to act as a heatsink, becoming noticeably warm in use, but the manual advises that this is normal. The remote control is as weighty as it is comprehensive, containing separate sections for CD player, iPod and amplifier control. It proved somewhat fussy about aim and sometimes took a couple of presses before the amp responded.


Regular readers will know that I use a Leema Tucana as one of my reference amplifiers, so you can imagine the zeal with which I unboxed the Tucana ll. Anyone used to the original would instantly recognise the company sound. Fast and quite richly toned, my attention was immediately drawn to the bass where I found a whole new degree of speed and accuracy, as well as depth, compared to the oldie. I was impressed by the separation of detail and the speed at which sounds stopped and started. By comparison the bass from my early model Tucana sounded a bit soft and wallowy. Moving up the frequency scale and I found greater space around sounds and a more defined shape to them.

Digging into my jazz collection, I put on Chris barber’s Bandbox Vol.3. This 1960 mono Columbia recording was made as the British Trad Jazz movement was beginning to fade away. Barber was one of the driving forces of the music from its roots in late 1940s Soho, and this LP showcases re-recordings of some of his classic tracks with vocals provided, as ever, by Ottilie Patterson. The Tucana ll relayed the sound in a very engaging and energising manner, producing a sonic image that occupied about three quarters of the space between the speakers. Stage depth was aided by the feeling that the sound extended forwards as well as behind the speakers.

Rhythm driven music seemed to suit the Tucana ll’s somewhat vivacious nature. Moving to stereo with “Latin Jazz Dance Classics Vol. 2”, and I found Cal Tjader’s track ‘Manuel Deeghit’ slinking out of the speakers with all of the hip-swinging groove that you would expect from a master of South American sounds. It was elegant, poised and seductive.

Later in the evening I had slowed things down a little and was listening to Rubenstein playing Chopin Nocturnes. Here the Tucana ll displayed a more considered and thoughtful side to things. The delicate touch of the fingers caressing the sounds from the piano was absorbing listening. The last LP I played on the Tucana ll was ‘The Orb Live ’93’, so it was the first on when the Stello Ai500 took over, and I was initially rather surprised at the closeness in sound between the two units.  Both had a similar sense of pace, and a similar tonality when presented with electronica, but began to define themselves when more conventional sounds took over...

The Stello Ai500 played the Chopin beautifully, possibly in a more thoughtful way than the Tucana ll. I felt that I was focusing on different aspects of the performance, perhaps less on the tonal colours of the music and more on the shape of it.  Moving back to the jazz and the difference in the presentation of the soundstage became apparent with the Chris Barber LP. The mono image was a little wider, nearly coming to the inner edges of the speakers, but stayed behind the line of the cabinets, extending to a moderate depth. Stereo had a similar presentation, this time extending sideways beyond the speakers further than the Tucana ll managed, but lacking the latter’s depth projection abilities.

Playing Cal Tjader confirmed a feeling that I had begun to have while listening to the Chris Barber tracks. I felt that the Stello was a little more straight laced when it came to the beat of music. The presentation seemed to lack a certain sinuous sensuality, seeming to lose a certain element of the passion that fuels good dance music, be it latin, trad, swing or whatever.

As computer-based music becomes more commonplace more amplifiers are being produced with onboard digital to analogue convertors. These allow a USB lead to link your computer’s hard-drive into the amp’s DAC, rather than using the often poor quality soundcard and headphone socket fitted to most computers. The Stello’s DAC proved to be a very good performer when fed from my MacBook via the USB input. In certain aspects it seemed to have the edge over my Cambridge Audio DacMagic 3, despite the latter’s upsampling capabilities. The sound was smooth, slightly rounded, nicely detailed and shown in a satisfying way.

An interesting pair of integrateds then, with subtle but nevertheless marked contrasts. How then do they stack up in the great scheme of things? Well, at this point the Sugden IA4 was duly heaved in. Actually, it stands as a testament to the quality of the Leema and Stello amplifiers, both running in Class AB, that they managed to stand their ground against a pure Class A design. I’d concede that the Sugden had a slight advantage in the smoothness of the sound, being seemingly seamless from bottom to top, but it still showed a little forwardness in the upper midrange when provoked by female operatic voices and trumpets. If not shrill, it is certainly ‘well lit’.

Both the Leema and the Stello exhibited better control in the bass arena when volume levels rose. The Sugden didn’t have quite so finely tuned handling in this area. But where the reference Sudgen won hands down was in the size, shape and openness of the soundstage. I can honestly say that it filled the room. The usual parameters by which I judge such things were completely recalibrated; moving back to the Class AB amps and the sound retreated to its conventional boundaries.

After readjusting my ears to the more restrained scale and presentation of the Ai500 and Tucana ll (rather like swapping from a V8 engined car to a straight 6) I ransacked my record collection trying to pinpoint the subtle differences in the way these two amps made music. Apart from the more upright timing of the Stello, they both seemed pretty impervious to musical genre, but displayed the sound slightly differently. If you can imagine the subtle hue differences between the same picture taken with Agfa film and with Kodak. The former gives a slightly cooler, bluer tint to things (the Stello), where as the Kodak version shows off the vividness of gold, reds and yellows (the Tucana ll).


In a sense, I found this a difficult review to write, because both the Leema Tucana II and Stello Ai500 integrateds are very persuasive in their own respective ways. They present music very well, and in a lot of aspects such as power and grip, they are very well matched. Ultimately the choice comes down to nuances of presentation. In the same way that Beethoven’s music is equally valid when conducted in a considered manner by Otto Klemperer, or in the more impassioned style of Toscanini, so both the Leema and Stello have equally valid viewpoints. I could live with either happily, although my personal preference would be the Tucana ll. I usually reach for the Toscanini/ Beethoven set because I love the temperament and fire that he conjures up, and I find the Klemperer style a little too cerebral.

Both amplifiers are not the best at the price, but arguably the best all rounders around. The reference Sugden had an obviously superior sound in respect of the breadth of the recorded acoustic, and the clarity was superb. But it wasn’t faultless in the bass, and certainly wasn’t as forgiving as the Leema and Stello in their own different ways. You could say that the Leema offers things up in a lovely, exuberant way, whereas the Stello steps back slightly and gets a tad more accurate in so doing, whilst the Sugden lays things bare, and can be variously magnificent or stark and even hard.

There are of course other considerations, such as the digital connectivity of the Stello which will appeal to some, but still the Tucana ll has a greater number of analogue inputs which will be more convenient to others. The Leema remote is less comprehensive but very responsive, and I preferred the feel of the fascia mounted controls. In terms of finish, I think the Stello won the day convincingly, and that’s really something because the Leema was already superbly well put together. The reference Sugden I am afraid to say wasn’t quite a match for either in this respect.

So, as ever, the best advice is to listen for yourself, but be prepared for some serious headscratching with this pairing. Both are extremely fine sounding amplifiers that wouldn’t disappoint even users of premium pre-power amplifier combinations. They’re both well built and finished, sporting friendly user interfaces to make ownership a pleasure. Both come from companies with established pedigrees, and as I said before both have a very convincing way of playing the music. Which way is your way, I leave to you...


Clearaudio Master Solution/Satisfy/Ortofon Kp. a turntable

Holfi Batt2riaa phono stage

Whest PS30R phono stage

Sugden IA4 integrated amplifier

Chario Ursa Major loudspeakers

verdict five globes

Wonderfully sweet and natural sounding integrated with a musical heart. Fine styling and build complete a great package.


Leema Electro Acoustics Ltd. 

+44(0)1938 811900


- power

- natural timing

- imaging precision

- rugged build


- over rich tonality

verdict five globes

Highly focused and super-clean sounding integrated with detailed, expansive sound. Brilliant build and handy feature set, too.


April Music Inc.

+82 2 3446 5561


- power

- expansive soundstaging

- fine onboard DAC

- immaculate finish


- cool tonality


The Tucana II delivers 162 Watts into 8 Ohms, measurement shows, rising to 272 Watts into 4 Ohms, very high levels of power. Leema warn it has no output protection circuits so a short will cause damage. The advantage of this, they suggest, is that current limiting does not exist to degrade sound quality. With a high damping factor of 74 the Tucana II will exert strong electrical damping and help tighten up loudspeakers that are acoustically under-damped and waffly.

Bandwidth was wide, stretching from 3Hz to 102kHz, the upper limit matching that of 192kHz sample rate sources. Input sensitivity measured a normal 300mV through both the normal phono socket CD input (unbalanced) and the balanced XLR CD inputs. Measured performance through XLR was similar to that via the phono sockets

Distortion levels were low right across the audio band, measuring just 0.001% at 1kHz and 0.005% at 10kHz, both at 1 Watt. Our analysis shows a progressively reducing harmonic structure with second harmonic dominant and this pattern was maintained as power increased, so the Tucana II has a dynamically stable transfer characteristic and should sound easy on the ear as a result.

The Tucana II is a high power amplifier that measures well all round. It should provide fine sound quality. NK

Power 162 Watts


Frequency response 3Hz-102kHz

Separation 82dB

Noise -91dB

Distortion 0.005%

Sensitivity 300mV




The Stello Ai500 delivers 153 Watts into 8 Ohms under measurement, rising to 240 Watts into 4 Ohms, so there is no shortage of power. The Ai500 has an unusually high damping factor of 126 so it will exert very strong electrical damping and will sound ‘tight’ in its bass quality, especially with loudspeakers that are acoustically under-damped and boomy, where it will apply useful control.

Distortion levels were very low right across the audio band, measuring just 0.002% at 1kHz and 0.006% at 10kHz, both at 1 Watt. Our analysis shows second harmonic dominates and this was the case right across the audio band, at all power outputs. The Ai500 has certainly been carefully engineered to achieve this unusual property and it does make for an easy and natural sound.

Measuring 320mV in for full output, the balanced XLR socket CD inputs have half the input sensitivity of the normal phono sockets, but both figures are good. Measured performance was otherwise similar through both inputs.

Bandwidth was wide but limited all the same, stretching from 10Hz to 68kHz

The S/PDIF digital inputs, optical and electrical, have a pronounced high frequency roll off, measuring -1dB at 17kHz with 44.1 and 48kHz sample rates. This will slightly smooth the sound from digital sources; it isn’t enough to make them sound dull or warm however. Linearity was good, distortion at 0dB measuring 0.002%, and at -60dB a normal 0.22% with 16bit and 0.08% with 24bit digital code, both results being as good as it gets, so the Ai500 has linear D/A convertors.

The Ai500 is a very carefully engineered amplifier that is likely to have very good sound quality. NK

Power 153 Watts


Frequency response 10Hz-68kHz

Separation 85dB

Noise -90dB

Distortion 0.006%

Sensitivity 160mV





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