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  • Tubes: 2 X 12AU7  4 X 6922  4 X KT88
  • Power output:  2×45W (8Ω ULTRALINEAR); 2x 80W (4Ω ULTRALINEAR)
  • Input: 4 x RCA
  • Frequency response: 10Hz60kHz
  • THD: 1%(1kHz)
  • Input sensitivity: 180 mV
  • Input impedance: 50 KΩ
  • Output impedance: 8Ω, 4Ω
  • S/N ratio: > 88dB
  • Dimensions: 450×430×240mm
  • Weight: 34Kg
  • Power consumption: 550W

The S-40 Integrated Amplifier is designed for those who seek the simplicity of a single chassis system with which the performance and the beauty of appearance are combined perfectly. 40 watts (8Ω)or 70W (4Ω) per channel is not a power monster, but heavy duty monster output transformer used in this unit makes it a great exception among mid power peers.  The net weight of the unit is over 80 lb, most of which come from enhanced StereoKnight output transformer.           

                     Click to S-40 high definition gallery

The S-40 looks pretty, modern, but built sturdy like a new age tank. With the enhanced transformer heart, it is capable of driving a wide range of loudspeakers. The sonic characteristic is crystal transparent, musical 3-D sound, and solid bass support.  

 Tubes in S-40

12AU7 is used for first stage amplifying and 6922 tubes for second stage. Both tubes are popular small tubes that have plenty of stock in the market at low cost. KT88 or 6550 are used for power amplifying. We favor the KT88 or 6550 not only due to its superior reliability nature, but also becaue we are so confident of making high power output tubes like KT88/6550 to deliver dynamic sound with most SET characteristic by applying zero negative feedback technology in high power pushpull frame. ZERO-NEGATIVE-FEEDBACK concept and technology are fully applied in both preamp and poweramp stages in S-40's design and engineering. This unique feature brings single ended class A only sonic characteristic to S-40's push-pull based nature.



Technology & parts

MOSFET technology is used to stabilize voltage most precisely, which offers faster rectification, and has the ability to address a much higher capacitance than the older tube rectifiers. Tube rectifiers are designed to handle only 50 microfarads (mf) at maximum, while MOSFET rectifiers can handle capacitances greater than 4000 mf. MOSFET also offer far better reliability and don't age as quickly as tube rectifiers. Tube rectifiers age and eventually short out the power supply cap, which is an expensive repair. It can also help to reduce electro-magnetic noise ( dead silent background) and operate unit more stably and reliably.

 Actually, all components and each measurement which may improve sound performance or enhance the reliability of the unit will be under careful consideration. StereoKnight do design and manufacturing all from picky and ambitious audiophiles’ view.  For example, most wires connecting parts inside chassis were covered by TEFLON tube --- (Teflon insulated wire is more suited to the higher working voltages. High voltages run on separate wires avoid copper crystallization (whiskers, due to high voltage) --- between layers of fiberglass when high voltage is run on PC board traces. Teflon wire also has better thermic stability and can withstand higher current for a short time).

In addition, some wires were hand made by compositing several kinds of selected enameled wires in proportion.  We also widely used Japan made POCC rectangular solid core copper wire as the wire inside the unit for passing the signal, which is usually used by big brand to make high cost interconnect cables.

 The following are some feature highlights:                                                                

  • High quality and heavy duty StereoKnight power supply components, output and power transformers.

  • High end components (Nichicon and Hovland capacitor), parts (StereoKnight designed heavy duty gold-plated binding post) and wire (TEFLON insulated wire and Japan made POCC rectangular solid core copper wire) all the way.

  • ZERO-NEGATIVE-FEEDBACK in both preamp and power amp stages.

  • Relay switching resistance volume and mute control technology with custom remotewand–high cost but least damage to sound, and reliable.

  • MOSFET voltage stabilization.

  • All-tube full preamp line stage

  • High control power, capable of driving a wide range of loudspeakers.

  • Easily accessible individual output tube bias measurement and adjustment points on side chassis.

  • Detachable IEC power cord, high quality gold-plated StereoKnight custom binding posts and RCA jacks.

  • Full high quality aluminum alloy body construction, modern style curvaceous faceplate and acrylic enclosure cover design: sturdy built with art. 

And do not forget modern style appearance designed by StereoKnight, full armed with high quality aluminum alloy faceplate, chassis and acrylic, the art of metal and crystal.

SIMPLE, BEAUTIFUL, RELIABLE is the compact oath StereoKnight born for. With 18-MONTH WARRANTY, the S-40 will give you lasting value and listening pleasure for years to come.




Copy right® 2007 Stereoknight HiFi Technology LLC. All right reserved, the art of design & engineering / 7890 Grove Ct. E. / Germantown, TN, USA 38138 
Phone: 1-901-283-0073 / Fax: 1-901-248-6866 / email: info@stereoknight.com / sales@stereoknight.com