The Sansui AU-XX00 line of integrated amplifiers are all
about reproducing the depths of musical performance. Like its ‘ancestors’, the
triple digit series from the late 1960s, the music is realistic, warm, and
detailed. But the extra that this series offers is that intangible soul
element. Voices were delivered from both heart and mind of the performers.
Every instrument carries their players’ emotions and moods. I am not
exaggerating. This musical authenticity belies the very plain looks of the
series – no shiny polished aluminium fronts, except for the parallel budget
AU-2200 to AU-7700 models – or multiple lighting points or gilt-edged knobs.
Their chief characteristic look is just naturally shiny aluminium knobs set against
the black front plate for the vast majority of the models. In fact, the AU-5900
to AU-7900, along with the parallel AU-5500 to AU-7700 all look nearly
indistinguishable until you look at the model number and the specifications on
paper. As is typical of 1970s stereo kit, the transformers are the C-core type
sealed black boxes and are individually very heavy.
What follows here is a non-technical analysis delivered in
short snippets of impressions. Moreover, one is never wealthy enough to have
owned every single model in order to review them thoroughly! If you are
planning to dig into this particular SANSUI line, do it for the music. The
looks? Well, depending on your imagination, it looks ready made for
accompanying ROCK and HEAVY METAL music. Or, if you place it near classic
living room furniture, the machined steel knobs and switches evoke the 1970s
vibe of living room stereo, and one you would expect set up near a first
generation television set. In this review, I can only provide impressions of
the 2900, 3900, 4900, 5500, 7900 and the 20000.
The 2900 is a race car version of the equally famous AU-101. All the trademark warmth and reasonable soundstage retained, but with a strong feel of power. According to HiFiengine.com ‘“The Sansui AU 2900 is an integrated stereo amplifier with ample power (17 watts, both channels into 8 ohms, at 1000Hz) and dramatically low-distortion, clean tone characterise the most moderately-priced of the AU Series. It's design is also based on the true complementary OCL power circuit, with dual-transistor differential amp in the initial stage. Dual plus/minus power supply for all major circuits gives you interference-free, stable tonal quality at all reproduction levels.’ Despite its conservative power rating, the AU-2900 is a daring example of exquisite Sansui engineering packed into a budget frame. Mind you, it can fill more than a small room the size of a high-end Hilton hotel executive suite. The AU-2900 is known to have driven Mission, Focus Audio and JBL speakers comfortably. I ran the 2900 hitched up to the massive 8 Ohms PATHOS Frontiers Prime and Emmespeakers Copernicus floor standing speakers and the sound was spacious without a hint of strain since I never needed to turn the volume beyond the nine o’clock position. Any higher in volume, one might start developing hearing problems after repeated listening! That said, when I compared the 2900 to the AU-7900, which is slightly over three times the power output, the 2900 revealed some limitations. The soundstage was much more detailed and richer, and the 7900 managed to elicit an emotional response from listening to soul and operatic vocals that the 2900 did not. This difference I suppose is reflected in the 7900 selling at more than twice the price of the 2900. Nonetheless, the AU-2900 exhibits the classic look of the Professional series with its unmistakable black fascia, punctuated by silver aluminium knobs and push buttons that convey the aura of 1970s Japanese Hi Fi glory.
What about the music? I have to rave a little since this is
indeed quite an exceptional entry level model. Although not the best for
classical strings and solo piano, it is stunning when vocals (rock, pop) and
all manner of jazz are played through it. Vocals are usually recorded at loud
volumes or intimate studio settings, and here is where the 2900 excels. With
plenty of bass and treble, you will easily forget it is just rated at 17 Watts
output at 8 ohms. Same experience with jazz, recorded again in compact settings
and fortissimo styles. Vocals, saxophones and trumpets stretch out very
noticeably many notes and passages, as a live performance will do. The 2900
picks up these nuances and other emphases as the performer intended it.
The next step up, the AU-3900 {picture above}, reveals a markedly improved body and refinement to the music. In fact, I was so impressed with the 3900 as to dub it a budget version of the 5900-7900 models. Just five watts more in power i.e. 22 Watts, plus perhaps more sophisticated coupling of capacitors produced a richer sonic experience. The soundstage and clarity improves upon the 2900 for sure. The X-factor for this one lies in showcasing the musicians and the music directly, as if they were standing or sitting in a spotlighted stage in front of you. And the music leaves you thinking affectionately about the lyrics, tones, and emotion long after the song has ended. It is truly that exceptional! I would dare say it is more than a concert experience in any genre of music. So if it comes down to choosing the 2900 or 3900, the latter should be the automatic choice, but not by a lot.
The AU-4900 looks remarkably similar in its façade to both the 2900 and 3900. The difference lies in a slightly larger transformer – the sonically beautiful C-Core type – that pumps out 38 Watts, or 35 Watts, depending on whether you believe hifiengine.com or classicaudio.com. The 4900 does seem a little louder than both its lower-level cousins at volume 2 and 3 settings and thrills just about the same as the entry-level 2900 for pop and rock vocals, as well as jazz. The key separation in quality lies with the reproduction of a large string orchestra. The 4900 outperforms the 2900 in the refined sound of adagios and pianissimos. Slowly played, and softly played music is brought to life in a very impressive way. What about a comparison with the 3900? Given the choice between the 4900 and the 3900, I would opt for the 3900 for a richer dynamism and its all rounded qualities. The 4900 impresses like the 2900, in addition to its specific mastery of reproducing classical music, but strangely, it does not leave you with a lasting ‘aftertaste’ of a great performance. Something seemed missing in the emotional department even after ‘living’ with the 4900 for six months. That said, the 4900 may be summed up – subjectively of course – as a technically excellent amplifier but not one that leaves you with an impression of greatness or the ‘wow’ factor.
The next two I have owned and tested – the AU-5500 and AU-7900 – cover the mid-tier of this series in tremendous style. The 5500 comes out of a so-called ‘budget’ parallel line ranging from the AU-2200 to AU-7700, as far as I know. But the quality does not sound budget to me. The sound of the AU-5500 can be described as warm, realistic, almost 3D like and it can comfortably drive almost any speaker up to the 300 Watts ceiling. Do not be fooled by its officially stated 32W power output, it sounds more like 100 Watts since this is a classic 1970s Sansui engineering design. In addition to double TAPE deck RCA outputs, one Tuner RCA output, one PHONO RCA output, it also has two AUX outputs. All RCA outputs allow connections to CD players, Digital/Analogue tuners, MP3 players and Bluetooth adaptors so this is an all-compatible machine able to extract an analogue sound from even the most digital music sources!
Power output: 32 watts per channel into 8 Ohms (stereo)
Frequency response: 10Hz to 35kHz
Total harmonic distortion: 0.15%
Damping factor: 30
Input sensitivity: 2.5mV (MM), 100mV (line)
Signal to noise ratio: 70dB (MM), 85dB (line)
Channel separation: 50dB (MM), 55dB (line)
Output: 100mV (line), 30mV (DIN), 0.8V (Pre out)
Speaker load impedance: 8 Ohms (minimum)
Dimensions: 434 x 130 x 315mm
Weight: 10.4kg
This amplifier is OUTSTANDING in reproducing vocals in big
concert/recording venues and jazz of all kinds. For pop and rock, it offers the
sonic punch and electric atmosphere of the original performance. It comes
across as blending McIntosh and Audio Analogue Hi Fi technologies.
The AU-7900 continues where the AU-4900 and 3900 left off, by amplifying their good features. The 7900’s industrial glamour on its front and back belied its power and mastery of subtlety. Listen to vocals, and you’ll hear the wow factor in the singer’s expression. A vintage singer like Rosemary Squires, Peggy Lee or Tony Bennett will reveal new soul in their voicing. Established classical voices like Maria Callas, Kiri Te Kanawa, Renee Fleming and Andrea Bocelli will demonstrate rich variations in their timbres. An emotive voice like Barbra Streisand will tug very deeply into your heart strings. And orchestras and quartets will span a soundstage as broad as your listening space will allow. This is a music dreamer’s gift!
I wish I had the opportunity to sample the AU-9900 and AU-11000, but I suppose that is another gap to be patched when funds allow. Finally, the AU-20000: a huge mammoth valve-sounding integrated amplifier without valves!
Power output: 170 watts per channel into 8Ω (stereo)
Frequency response: 10Hz to 50kHz
Total harmonic distortion: 0.05%
Damping factor: 80
Input sensitivity: 3mV (MM), 130mV (DIN), 130mV (line)
Signal to noise ratio: 70dB (MM), 80dB (DIN), 80dB (line)
Channel separation: 55dB (MM), 60dB (line)
Output: 130mV (line), 30mV (DIN), 0.7V (Pre out)
Speaker load impedance: 4Ω to 16Ω
Dimensions: 460 x 178 x 400mm
Weight: 23.6kg
Year: 1976
The opinions out on audiophile sites across the Internet
are split in their verdict. The negative views focus on its seemingly
underpowered bass, requiring the boosting effect of the bass knob. Worse, some
argue that the lower powered models in this series supply more dynamic bass
than the one touted as top of the line. My initial impressions matching the
20000 to modern speakers such as my all-time favourites, the PATHOS Frontiers
Prime and the Emmespeakers Da Vinci, confirmed some of these disappointments. I
missed the power and grace of the AU-7900, and even of the later product, the
equally massive AU-919. I found out that substituting the factory supplied
power cable for the 20000 for thousand dollar power cords actually reduced the
bass, and introduced excessive transparency to the point where the music – both
vocals and instrumentals – sounded flat, two dimensional and nearly lifeless.
Refitting the power cord with a factory standard normal copper cable restored
much of the bass. But it still seemed less engaging than the 7900. I was about
to consider selling it off, when someone suggested matching it with WESTERN
ELECTRIC (WE) power cords. I got myself the first available pair which turned
out to be unused ‘new old stock’ from around the 1942-5 period terminated with
IEC socket at one end and hospital/UK plug at the other end.
The WE cord turned out to be the ultimate fix. The bass now revealed refinement, spaciousness and even layers of subtlety unheard of before. This was not just the dynamic bass of the lower level models. It was more revealing. And one has to gradually let it grow its own unique endearment. Vocals, instruments now demonstrated concert quality three dimensionality, as far as the original recording permitted. In fact, one should re-listen to everything one has developed familiarity with. You will hear something new through the 20000. Try Nat King Cole, Sinatra, Peggy Lee, or the newer voices of Diana Krall, Nicki Parrott and Madeleine Peyroux, and you’ll hear a new poignancy to their song. Violins are uncannily ‘live’ especially if they are classical recordings. And this is not a tube production from SANSUI. Open up the hood, you will even notice that SANSUI fitted what looked like an enormous toroidal transformer instead of the usual C-core. And notice those mega-sized capacitors next to them.
So there you have it – the AU-20000 has turned out after a slight tweak to be a massive valve-like amplifier, boasting unbelievable refinement and a machine quite unlike the rest of the range. Why did it have to be so? I suppose SANSUI wanted this series to be outstanding. The top of the line literally had to be different yet produce some sort of culmination from the tasting sensations with the already exceptional AU-2900 and AU-3900.
ALAN
June 2024
