Audio Database

AU-111vintage1999
Commentary

This is a pre-main amplifier that restored the original attractiveness in 1999, 34 years after the AU 111, which was developed as the last vacuum tube amplifier of Sansui by gathering all of the technologies.
Although the naming is different, in order to retain the charm of the original model, the front panel has inherited the same AU 111 logo as it was at that time.

We re-examine it from the point of view at the time of re-printing in order to correspond to the latest source.

Based on the specifications of the output transformer at that time and the engineers involved in its design and manufacturing, we restored and adopted the SW (Super Wide) type output transformer with large capacity output (guaranteed 30Hz/50W continuous output), low loss (0.25 dB or less), ultra-wide range (20 Hz to 100 kHz), and NFB margin (25 dB).
Since it uses a complicated winding structure, each piece is finished by hand by skilled engineers.

The power tube, which is the key device, uses the Svetlana brand as a result of repeated testing of 6L6GC power tubes obtained from all over the world. It is operated by 6L6GC push-pull with AB, P. P. fixed bias.

The circuit configuration of the power amplifier provides sufficient open-loop gain and uses a leak Mulard type that is easy to adjust AC balance.
The first stage uses 6AQ8, which has high instantaneous power and can operate at high current, and the phase inversion uses 12BH7A, and the S/N of the auditory sense is obtained.
The control amplifier uses a 12AX7 4-stage amplifier circuit including the cathode follower. All of the control amplifiers are 2-stage amplified NF amplifiers, and a low-impedance output preamp can be used independently.

For analog record playback, the phono equalizer is a 2-stage amplified NFB configuration of 12AX7, and it is compatible with MM cartridge with perfect shift.
In addition, the MC cartridge has a separately sold A-603S type input transformer in the MT9P socket.

The internal wiring is completely hand-made direct wiring without using any boards as it was at that time, and the sound quality change caused by using boards is cleared.

The power supply section uses a large and large-capacity type power transformer that SUNSUI specializes in excellent regulation. It draws 480 v high voltage by double-voltage current and supplies it to the 6L6GC plate.
Since the screen grid has large voltage fluctuations and cannot obtain stable high power, a Blater resistor is installed to stabilize it and enable large output.
Also, you can enjoy the change of sound quality by using the detachable power cable.

In addition to the low / high filter of the CR feedback system, it is equipped with an accessory circuit such as a loudness control, a presence control to improve articulation in the low frequency range, and a tape monitor.

To support digital sources such as SACD and DVD-Audio, it is equipped with Route 6 input via all-gold-plated input jacks.

Uses a gold plated terminal corresponding to speaker impedance of 6 Ω ~ 8 Ω and 16 Ω.

The main chassis is made of stainless steel for sound quality and long-term use.

The oil condenser (No PCB), carbon resistance, and vacuum tube socket are used as parts to keep the original tone.
In particular, oil condensers used for couplings have a significant effect on sound quality, so oil condensers are installed in all couplings as they were in those days.


* The following are supplementary items included in the catalog.

In order to make the most of its capabilities, SANSUI recommended a combination of speakers such as WestCoast speakers (ALTEC and JBL), coaxial speakers (TANNOY), and BBC monitor speakers (spendor).

Repeated ON/OFF of the power switch is prohibited. When turning the power off, wait at least 30 seconds before turning the power on.
If you turn on the power immediately, a large current will flow and damage the vacuum tube.

Model Rating
Type Stereo pre-main amplifier
Maximum practical power 45W/45W (8 Ω, 16 Ω)
Effective power 40W + 40W (8 Ω, 16 Ω)
Frequency characteristic 10 Hz ~ 80 kHz + 0 -3dB
Total harmonic distortion factor (at effective output) 0.8% or Less (8 Ω)
Mixed harmonic distortion factor 0.8% or Less (8 Ω)
Damping factor 15 (8 Ω)
Input Sensitivity / Input Impedance
(1kHz)
Phono MC High/A-603S : 0.25mV/30 ~ 100 Ω
Phono MM : 4.0mV/100k Ω
Tuner, CD, Line-1, 2, Tape : 250mV/300k Ω
Rated power consumption 210W
External dimensions Width 460x Height 197x Depth 433 mm
Weight 26.0kg
Sold Separately : MC Cartridge / Matching Transformer A-603S (1 pair, ¥ 16,000)
Corresponding impedance 30 Ω ~ 100 Ω