Atma-Sphere S-30

High End OTL Tube Amplifier, 2 x 30 Watts, Mk 3.3

The S-30 is the unchallenged state-of-the-art in low power vacuum tube amplifiers. With its simplicity of operation, small footprint, and all the features of our larger amps, the S-30 represents the high-water mark of compact OTL design.

For those who seek the ultimate in amplifier design the S-30 gives you the same precision and sound quality for which Atma-Sphere is known. Featuring automatic bias and a large VU meter, operation is elegantly simple.

Because it utilises decades-proven patented handwired circuitry, it is stable with any load and both performs and sounds better than any single-ended amplifier ever produced, let alone conventional push-pull designs. Its fully-balanced design and proven class-A triode operation make the S-30 the ideal choice for the discriminating audiophile.

FEATURES

– Balanced Differential Design®
– Class-A operation
– Patented Circlotronic® direct-coupled (OTL) output stage
– Dual-mono chassis construction
– Automatic bias – no adjustment needed
– Built in VU meter for tube and output monitoring
– Easily monostrapped for greatly increased power
– Uses only one gain stage for supreme clarity of sound
– Proprietary precision components used throughout
– Low-noise “star” grounding topology
– Fully hand-wired point-to-point electronics – no circuit boards!
– Stable with all input and load conditions
– Exclusively uses Octal-Triode based vacuum tubes
– Classic open chassis construction with Wrinkletex™ finish
– Three-year general coverage warranty, one year warranty on output tubes

Output power
30 watts per channel into 8 Ω
45 watts per channel into 16 Ω

Impedance
Input Impedance: 100 KΩ single-ended, 200 KΩ balanced Output Impedance: 7 Ω

Input
3 V sensitivity
RCA and XLR true balanced input

Tube complement
10 x 6AS7G output tube
6 x 6SN7 driver tube

Gain
23dB (for 8 Ω)

Power Bandwidth
2Hz-75KHz within ½ dB

Frequency response
(1 watt, open loop) 20 Hz squarewave Tilt, unmeasureable
1Hz-200KHz within 3 dB

Hum and noise
Less than -75db below 1 watt,
-95db below full power (30 watts)

Distortion
Total Harmonic Distortion (THD) typically 1% at full power.
Intermodulation (IM) distortion typically under .04% at full power.
Phase shift less than 1° @ 20KHz

Output section risetime
600 V/µs

Feedback
2 dB

Power consumption
400 watts

Dimensions & Weight
13″ deep x 17″ wide x 8″ tall ( 33 x 43 x 20 cm )
24 lbs ( 10.9 kg ), without tubes