Hi. I realize this thread is about 7 years, but it’s very relevant to me as I’ve just got the same amp (StereoKnight Lancelot S40) Just as the thread starter, I’m not able to find any information about this integrated amp. Would really like to know a bit more about it, and also info conserning the bias system So therefore I respond to this old thread. Hope someone has some info about it (What a beauty of an amp this is 😊) |
Congrats aasbakk, you have found a great amp. I didn't know anything about StereoKnight or the S40 when I got mine, but after having it for a decade, and having bought several other amps, I do know now, how special this amp is (still have it, probably never let it go). Sooo... I did some digging to find out how to bias it. I discovered one of the two StereoKnight principles (the tech guy), started another audio company in Australia, and I was able to find out from him how to set the bias. You do use the four RCA connectors that are behind the little square panel on the left side of amp. Each RCA connector correspond to an output tube. The RCA connector is used with an external voltmeter. RCA + connects to meter +, RCA - connects to meter -. (Note: the built-in amp meter does not work on the S40 - it's not even wired - I looked.) Basically, the RCA connector lets you connect a voltmeter across a 10 ohm (cathode resistor). The bias specification is 45ma, so 45ma across the 10 ohm resistor produces 450mV. This is what you'll read on the meter, 450mV or .45 volts. So the bias steps are; 1) Hook up voltmeter to RCA connector #1 (to bias tube #1 - tube furthest right) 2) Turn on amp with no input signal, volume at 0. Let tubes warm up for 5 minutes, and take measurement on meter. If not 450mV, use the tweak (potentiometer) next to tube #1, and set the voltage to 450mv. 3) Turn off amp and move voltmeter to RCA #2, and repeat. That does it. Hope you enjoy your amp as much as I've enjoyed mine. I'm currently running a set of Gold Lion KT88, NOS Mullard E188CC, and NOS Amprex 7316. Man-o-man does this thing sing! (FYI - Good NOS tubes in the front end really made a difference.) |
Thank you very much 😀 I really appreciate your help 😀 i god this amp in replacement for my Rogue eighty-eight, and man did those speakers come to life. The sweetness an dynamics are superb 😀 I run a pair of Audio Physic Virgo 1. Source is Roon server with Qobuz for digital, and a heavily customized Lenco L75 for analog very happy with my setup, and I’ll try biasing later this week btw. Do you know any technical specs for the S40?, and if there buildt riaa (I suspect there is only the name of the input, and not a built-in?) Again. Thank you very much for your response. It’s quite enjoyable being the owner of such a wonderful, and rare amp 😀 all the best Jon Anders |
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As this is the only info I find about this amp, I thought I’d share my findings over the years. Including specs Now running: This works very nicely I also have found specs on the S40 👍 Here it is: (quite a lot reading)
Specifications
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. 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:
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.
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