atelier 13 audio
SWISSONOR RS
A CAREFULLY SELECTED LINE OF AMPLIFIERS AND PREAMPLIFIERS
DESIGNED AND BUILT WITH GREAT CARE AND ATTENTION TO DETAIL
TRUE TESTIMONIES OF THE SWISS TRADITION OF TIMELESS
DESIGN AND UNCOMPROMISED QUALITY
HAND MADE - PRODUCT OF SWITZERLAND
General Intro
RS=Radically Simple
If you need more power to drive medium efficiency loudspeakers, without giving up the radical fidelity of Swissonor tube amps, this item is for you. The strictly double monophonic design using two huge toroidal transformers enhances an ultra sober design, composed of a passive line preamplifier and a single chip OPA per channel, without any intermediate stage.
An optional OP Phono amplifier in passive RIAA design, or an optional Digital to Analog Converter (DAC) make this a really versatile integrated component.
The Circuit
As an accessible high performance Swiss Made unit, the RS's rugged construction on a cast iron mainframe with decoupling elements translates the Swissonor philosophy into the universe of solid state technology :
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Shortest signal path, connectors and cables used for connecting separate components are eliminated.
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A design that eliminates impedance and gain mismatch and reduces the number of active circuits.
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One oversized power supply for each channel.
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Separate ground wiring together with central ground connection and ground lift for best signal purity and lowest hum and noise.
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Passive line amplifier followed by a single 3886 OPA power amplifier per channel
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High quality components all around, such as Block toroidal transformers, very long life low inductance capacitors, ALPS blue velvet volume control and double layer gold plated cardboards.
SWISSONOR RS SPECIFICATION
Class of Operation
Solid State Class A/AB
Operational Amplifier
1x single-chip 3886 OPA per channel
Input Voltage
120V/60Hz
Output Power
50 Watts @ 8 ohms / 80W @ 4 ohms
Input Sensitivity
500 mV
Input Impedance
50 Kohm
Frequency Bandwidth
5Hz - 100KHz (+/- 2dB)
b
Inputs
4 x RCA
1 x RCA Coax (digital-ready)
Price $ 5,199
SPECIAL OFFER (contact us) $ 4,780
MM / MC Stage $ 750 Special Offer $ 650
Handmade in Switzerland
About the 3866 Operational Amplifier ... and the RS
Making the best of a great Chip Amp
The National Semiconductor (now Texas Instruments) LM3886 chip amp is a pretty nice chip....so much so that folks like Jeff Rowland uses this chip (actually multiple LM3886 chips for higher power) in his highly respected amplifiers. 47 Labs, famous for the Gaincard used a stable-mate of this chip, the LM3875. However, for compatibility with 4 ohm speakers - and with more complex loads in general - the LM3886 is a far better choice, as the LM3875 is not well suited for loads below 8 ohm.
With headline specs touting nearly 70 W of output power at 0.03 % THD and the ability to source over 11.5 A, what’s not to like?
Well, as with any high-performance IC, it takes some careful and competent engineering to get the circuit to live up to the data sheet specs. In particular with power op-amps, such as LM3886, the PCB layout (or point-to-point wiring routes) make a significant difference in the circuit performance.
Urs Frei at Swissonor, whose amplifiers (except for the RS) are all tube-based, was not about to design a solid state amplifier that was not representative of the quality level of its tube brethren ... and in true Swiss tradition - meaning a no compromise and rigorous approach to design and Quality -- he "aced" the solid state circuit design challenge ... a challenge which requires very careful attention to key performance parameters, namely : stability, bypassing, grounding, layout, and thermal design ... all supported by a high cost dual-mono toroidal transformer power supply with a very generous current capability.
In a contradictory "twist" of logic, Urs named this amplifier the RS which stands for "Radically Simple" ... which sort of tells the story behind the effort and time he put into its development.
What is also fascinating - but perhaps not really surprising - is that the solid state RS has very appealing tube-like sound characteristics ... resulting in a magical "best-of-both worlds" sound ... a character also much loved by another notorious American design guru ... a certain "Nelson".
Handmade in Switzerland
