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Sansui77

Sansui AU-111, 907 NRA, Alpha 907 Review

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Sansui AU-111, 907 NRA, Alpha 907 - Review 2019

 

Sansui Nutters!!!!!

 

I have the pleasure in owning the following amplifiers from Sansui. Most of my collection is pre 1980's but i have started to get into the Alpha line from when the first Alpha's were released in the mid 1980's . This review is not biased towards any particular decade of the Sansui lineup but just my thoughts (opinion) on how they compare, but more importantly where Sansui as a company were heading towards it's sound signature before the end days when they closed in 2001 - 2002. BTW, I'll do my best to explain how they compare in their sound signatures.

 

1. The famous AU-111 tube amplifier (1966)

This has been restored with all tubes, caps & some resistors replaced as needed. Still has the original main filter caps fitted.

 

Specs

 

Power output: 40 watts per channel into 8Ω (stereo)

Frequency response: 20Hz to 50kHz

Total harmonic distortion: 0.8%

Damping factor: 15

Input sensitivity: 220mV (line)

Signal to noise ratio: 70dB (MM), 80dB (line)

Channel separation: 45dB (MM), 50dB (line)

Output: 2.1V (Pre out)

Speaker load impedance: 8Ω to 16Ω

Dimensions: 460 x 170 x 345mm

Weight: 24.5kg

 

IMAG0836.thumb.jpg.4c51d58769c854fa4b4ba77fc4756be1.jpg

IMAG0839.thumb.jpg.af3e4a800c533baa6865d45d94131f7e.jpg

 

2. Sansui Alpha 907 NRA (1998)

All factory original. No repairs or mods have been done to this. 

 

Effective output (10Hz - 20kHz)
Both channel simultaneous operation
190W+190W (6ohm)
160W+160W (8ohm)
THD (at the time of an effective output) 0.003% or less (8ohm)
Cross modulation distortion 0.003% or less (8ohm)
Dumping factor 150 (8ohm)
Frequency characteristic (1W) DC-300kHz+0 -3dB
Input sensitivity/impedance 1V / 10kohm (1kHz)
SN ratio (A network) 120dB or more
Dynamic power 580W (2ohm)
390W (4ohm)
310W (6ohm)
TIM distortion (SAWTOOTH) Below a limit-of-measurement value
Slew rate 200v/microsec
Rise time 0.5microsec
 
Input sensitivity/impedance
(1kHz)
Phono man month: 2.5mV / 47kohm
Phono MC: 300 microvolts/100 ohm
compact disk, Tuner, Line, micro disk/Tape1, Tape2:150mV/20kohm
Phono maximum permissible input MM(THD 0.01%):210mV
MC(THD 0.1%):21mV
the frequency characteristic (1W) Phono man month: 20Hz-20kHz�}0.2dB
compact disk, Tuner, Line, micro disk/Tape-1, Tape-2:DC - 300kHz+0 -3 dB
SN ratio (A network) Phono man month: 90dB or more
Phono MC: 75dB or more
compact disk, Tuner, Line, micro disk/Tape-1, and more than Tape2:110dB
Tone control The Bass maximum variation: �}6dB (50Hz)
The Treble maximum variation: �}6dB (15kHz)
Subsonic Filter 16Hz (-3dB), 6dB / oct
Loudness +4dB(50Hz)
+3dB(10kHz)
 
Power dissipation 400W
Dimensions Width 462x height 165x depth of 448mm
Weight 33.0kg

IMG_20190714_112027.thumb.jpg.77ce364297031f8e7559ac8fba7a8e2b.jpg

IMG_20190714_112056.thumb.jpg.40b9bc911de40adef60aebc4cff2d446.jpg

 

3. Sansui AU-Alpha 907 (1986)

 

Same as the NRA, all factory original. No repairs or mods have been done to this. 

 
Effective output (10 Hz to 20 kHz, both channels driven) 190 W + 190 W (6 Ω)
180 W + 180 W (8 Ω)
Total harmonic distortion (at effective output) 0.003% or less (8 Ω)
Intermodulation distortion factor 0.003% or less (8 Ω)
Dumping factor 100 (6 Ω)
Frequency characteristic (1 W) DC to 300 kHz + 0-3 dB
Input sensitivity / impedance (1 kHz) Normal: 1V / 5kΩ
Balance: 1V / 5kΩ
SN ratio (A network) 120 dB or more
TIM distortion (SAWTOOTH) Below the measurement limit
Slew rate ± 200 V / μsec
Rise time 0.5 μsec
 
Input sensitivity / impedance (1 kHz) Phono MM: 2.5mV / 47kΩ
Phono MC: 300 μV / 100 Ω
CD, Tuner, Line, Processor: 150mV / 47kΩ
Tape play / DAT-1, 2, 3: 150mV / 47kΩ
Phono maximum allowable input
(New IHF, THD 0.01%)
MM: 210mV
MC: 21mV
Frequency characteristic (at 1 W) Phono MM: 20 Hz to 20 kHz ± 0.2 dB
CD, Line, Tape play / DAT-1, 2, 3: 1 Hz to 300 kHz + 0-3 dB
SN ratio (at 1 W) Phono MM: 88 dB or more
Phono MC: 70 dB or more
Tuner, Line, CD: 110 dB or more
Tape play / DAT-1, 2, 3: 110 dB or more
Tone control Bass: ± 5 dB (50 Hz)
Treble: ± 5 dB (15 kHz)
Turnover frequency 75Hz, 150Hz, 7kHz
Sub sonic filter 16 Hz (-3 dB, 6 dB / oct)
loudness +8 dB (50 Hz), +6 dB (10 kHz)
 
Rated power consumption (Electrics Control Act) 370W
External dimensions Width 448 x height 160 x depth 441 mm
weight 28.0 kg

IMG_20190711_173632.thumb.jpg.660e13a1505da0a3d91fc3aa64dc4ec6.jpg

IMG_20190711_174448.thumb.jpg.eaa126fea148b9b38b1e7886fd7240a5.jpg

 

 

Setup:

Source: Asus mini laptop (optical out) using foobar 2000 through Matrix DAC.

Speakers: Spendor BC1 (Recapped x-overs) on open stands angled inwards but slightly angled outwards of listening position. Ear level position set between the Celestion HF1300 mid-range & Coles 4001G super tweeter. Distance 4 Meters from speakers to listening position.

Carpet room 7 x 3.5 meters.

 

"Let the product speak for themselves"

I had a good listen to both the first generation 907 and the NRA yesterday through my Spendor BC1's which I've decided to keep. I just couldn't sell them as they are such a great listen, very detailed speakers with a beautiful mid-range. The mid band /mid-range is the most important aspect of a great sounding system imo. The 907 was played in the morning then the NRA at night, same source same speakers.

 

First of all I must say the older first generation Alpha 907 is a damn good listen WOW!!!!! The 907 is not as detailed and polished like it's newer brother NRA but is the most powerful of them all @ 180Wrms per channel. It still a lovely listen and I could easily be happy to just own this and be done with it but I need to explore where Sansui was heading. Comparing to the NRA's sound, I would say the NRA comes across more finetuned a more polished sound with greater detail compared to the Alpha 907. It's not a huge difference but you can tell. The NRA settings @ flat are absolutely perfect. I was really surprised at whatever music I was feeding it, it just didn't require additional adjustments where both the Alpha 907 & AU-111 at flat are more bass heavy. Actually, the AU-111 is the most heavy on the bottom end and I had to back it off from 12 to the 9 o'clock position. I played all types of music yesterday and decided to put Madonna's immaculate collection on as I think it's a beautifully recorded & produced album, plus I remember listening to it through the AU-111 a while back and couldn't stop smiling. The NRA & the AU-111 are closer than I had thought from what I remember listening to the AU-111. They both have a beautifully rich smooth detailed accurate sound and both seem to do really well giving a 3D image with an amazing sound stage, it's that good. I would give the upper hand to the AU-111 in this department only because I feel it gives you a little more seperation in the sound stage. Apart from the 111's bottom end slam, they're almost identical in how they voice in the mid-range to the silky top end. The NRA i feel is a little cleaner - clearer in the SQ department but not by much and that also depends on what type of music is played at the time. Studio albums suits the NRA to a T for it's beautiful even control throughout the audio spectrum where's the AU-111 for it's bottom end would suits live performances. I feel that both are very close with little differences and Sansui may have tried to use the AU-111 as a reference standard but improving on making the sound even more detail with great success. The NRA and any Alpha for that matter are just beautifully built - sounding masterpieces. At the moment the AU-111 has a magical sound with an amazing sound stage that would make anyone listening to it smile and say, how does a 50+ year old tube amplifier sound so good.

 

Next is to get a couple more Alphas to the list and we'll see what happens with that.

 

 

 

 

 

 

 

 

Edited by Sansui77

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Very nice review Mark... 👍

Glad you did'nt sell those Speakers!

 

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Good work Mark, looking forward to more from you. Ahhh I'd love a 111, you're a lucky man. I haven't heard the other Alpha 907's except one of Jeff's newer ones on his Lenehan's. I could hear more detail in his as you said. I think the standard 907 isn't as detailed but is excellent for rock/metal/hip hop. It just has ample power sounds big. 

 

I tend to use my Plinius/Exposure for slower stuff with more detail. I haven't heard a 111 however it's on my bucket list. Do you think you could tell the 111 is a valve compared to the NRA or are they just too close?

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6 minutes ago, BLAH BLAH said:

Very nice review Mark... 👍

Glad you did'nt sell those Speakers!

 

Glad you didn't sell that amp!

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Good work Mark, looking forward to more from you. Ahhh I'd love a 111, you're a lucky man. I haven't heard the other Alpha 907's except one of Jeff's newer ones on his Lenehan's. I could hear more detail in his as you said. I think the standard 907 isn't as detailed but is excellent for rock/metal/hip hop. It just has ample power sounds big.    I tend to use my Plinius/Exposure for slower stuff with more detail. I haven't heard a 111 however it's on my bucket list. Do you think you could tell the 111 is a valve compared to the NRA or are they just too close?

 

 

Value wise, about the same mate. Both cost about the same for me anyway. AU-111 from Japan and the NRA was a local purchase. 

I love the AU-111 for its imaging and sound stage it throws out but the NRA is just so well built, quality components for what you pay for them. It's a credit to Sansui for making these masterpieces before they shut shop.

 

 

 

 

 

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