SANSUI AU-X1 HI-FI INTEGRATED AMPLIFIER RARE VINTAGE HIGH END PHONO SERVICED

Sansui AU-X1 integrated amplifier in full working order, measures within specifications has been rebiased and load tests fine. Comes with a comprehensive service including new preset controls, replacement of known prone to fail components, and all small electrolytic capacitors. This is late production model that has all the the factory performance upgrades. Condition is fair to good, some scratches to the front panel, see photos to confirm. This is an import model some comes with a UK power adapter, no other accessories or cables are included in the sale. Don't miss out on an opportunity to own this highly regarded rare amplifier.

Specifications:
An amp designed to pursue as much as possible the ideal that an amp should be a single conductor with a degree of amplification that faithfully conveys the music signal.

About half of the space is for the power supply. The form of independent 8 power-source stream composition is adopted to whole page right-and-left independence, a power stage, a pre-drive stage, a flat amplifier/equalizer, and MC head amplifier.
A 600VA high-capacity toroidal transformer and an 80VI/EI transformer are used. 8 x 10,000μF custom high-capacity electrolytic capacitors developed exclusively for audio are connected in parallel, and a 1.2mm thick copper plate is used in combination with the grounding circuit. For this reason, even if the speaker impedance fluctuates with frequency, the powerful power supply section provides stable operation.

Equipped with a diamond differential circuit. Furthermore, the newly developed linear high-speed output element NM-LAPT (Non Magnetic-Linear Amp. Power Transistor) is adopted. As a result, we succeeded in bringing TIM distortion and envelope distortion, which are dynamic distortions that hinder sound quality, to as close to 0 as possible.

From large die-cast heat sinkers to high-efficiency triple-braided speaker cord wiring, we carefully check the characteristics of each individual part and select them through interviews.

A power amplifier operation switch on the front panel allows separation of pre and power.

The power supply to the power stage uses a large toroidal transformer (power supply capacity 600VA) with good regulation with 2 windings and 2 rectifier circuits with independent left and right channels. In addition, custom large-capacity electrolytic capacitors of 10,000 μF x 8 developed exclusively for audio are connected in parallel, and a 1.2 mm thick copper plate is used in combination with the ground circuit.
Moreover, the left-right channel independent 2 power-source system by the large-sized EI transformer (power-source capacity 80VA) is used for the pre-drive stage, and a diamond differential circuit is strongly driven.
In addition, the equalizer amplifier section and flat amplifier section are supplied from left and right independent constant voltage circuits, and the MC head amplifier section is supplied from left and right independent low voltage circuits with separate windings.

Newly developed NM-LAPT with high speed, excellent linearity, high breaking strength and high cutoff frequency (ft100MHz) is used for the power transistor with triple push-pull connection and used at the operating point with excellent linearity.

The head amplifier section has a DC amplifier configuration that further advances symmetrical push-pull input/output using newly developed low-noise high gm P-ch and N-ch FETs. The first stage is a direct couple system with low noise, high gm P-ch and N-ch FETs connected in parallel to achieve ideal input impedance and a high S/N ratio with push-pull input.
In addition, the second stage is an MC amplifier circuit with excellent open loop characteristics and good linearity due to a push-pull drive two-stage direct connection circuit using a combination of NPN-PNP transistors.
Furthermore, extremely high stable operation has been obtained by right-and-left independence and power supply only for MC.

The equalizer amplifier section has a DC amplifier configuration equipped with a diamond differential circuit using a direct couple method. The first stage has good pair characteristics, adopts a differential input circuit that uses low noise, high gm, and dual FETs, and configures a cascode bootstrap circuit that is not affected by input impedance.
Moreover, by the high-performance constant-current circuit (PAT. PEND) which consisted of the two-step hardwired-connection circuit by the NPN-PNP transistor combination, CMRR (common-mode component suppression cost) in a summing point was taken high, and the outstanding dynamic characteristic has been acquired. The second and third stages are a diamond differential circuit with excellent drive capability + current differential push-pull, the output stage is a SEPP circuit with Darlington connection and has a sufficient current margin, and the low output impedance and low impedance NF circuit design provide a sufficient dynamic range even against changes in load impedance, and further improve the S/N ratio.

The flat amplifier adopts a push-pull drive DC amplifier configuration with a differential input circuit using a newly developed 1Tip (4- element enclosed) FET in the first stage, and achieves excellent operation by independent power supply for left and right.

The speaker wiring cord from LAPT adopts an ultra-low DC resistance, low inductance and high efficiency triple braid structure, and has obtained excellent transmission characteristics without deteriorating the slew rate.

A CP type (conductive plastic) master volume is adopted.Modelstereo integrated amplifier