Atma-Sphere S-30 Mk.3.3


[Contact us for a price]

In stock

Minimum quantity for "Atma-Sphere S-30 Mk.3.3" is 1.


S-30 Mk.3.3

Stereo Music Amplifier

Features :

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 audiophiles who seek the ultimate in amplifier design and are realistic about their budget, the S-30 gives you the same precision and sound quality that Atma-Sphere is known and recognized for. Featuring automatic bias and a large VU meter, operation is elegantly simple.

And 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.

  • 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

Specifications :

Output power

30 watts per channel into 8 Ω load
45 watts per channel into 16 Ω load


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


3 V sensitivity
RCA and XLR true balanced input

Tube complement

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


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)


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


2 dB

Power consumption

400 watts


13" deep x 17" wide x 8" tall ( 33 x 43 x 20 cm )


( without tubes ) 24 lbs ( 10.9 kg )