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Atma-Sphere MA-1

The best tube amplifier worldwide, 2 x 140 watts OTL monoblocs, Mk 3.3

Atma-Sphere MA-1

Recipient of The Absolute Sound's prestigious "Golden Ear Award" in 2000, the MA-1 enjoys an enviable reputation. Now the Mk. 3.3 series builds on proven technology. An improved output section and enhanced driver circuit contribute to superior low-level detail, smoother sound, wider bandwidth and AC power immunity. The rugged, non-magnetic chassis features classic looks with superior layout. Setup of the amplifier is simple with it's automatic biasing system. The controls and switches are ergonomic without sacrificing performance. 

The MA-1 is extraordinary in every way. Not only is normal operation easy on the vacuum tubes, the effect of a tube failure on the unit is entirely inconsequential. Despite its extreme performance, the MA-1 is known for remarkable ease of setup, ease of operation, day-to-day consistency and of course extreme musicality. 

Featuring our new custom wire, V-Cap Teflon coupling caps, custom resistors, and all the other extras for which we are known, the MA-1 shines as an example of why our amplifiers are the best amplifiers worldwide, regardless of cost.

Prix The Absolute Sound


- 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



Reviews & Awards

Marc Mickelson, Feb. 2002
Audio measurements, 2000
Sounds Like...
Laura Dearborn
Page 1Page 2Page 3 • Page 4Page 5
Various, user submitted

Output power
140 watts per channel into 8 Ω load 
135 watts per channel into 4 Ω load

Input Impedance: 100 KΩ single-ended, 200 KΩ balanced Output Impedance: ~2.3 Ω (power method standard measurement)

2.8 V sensitivity 
RCA and XLR true balanced input

Tube complement
14 x 6AS7G output tube ( per channel ) 
5 x 6SN7 driver tube ( per channel ) 

25dB (for 8 Ω)

Power Bandwidth
2Hz-200 KHz within ½ dB

Frequency response
(1 watt, open loop) 20 Hz squarewave Tilt, unmeasureable
1Hz-300KHz within 3 dB

Power supply storage
600 Joules ( per channel )   

Total Harmonic Distortion (THD) typically 0.5% at full power.
Intermodulation (IM) distortion typically under .005% at full power.
Phase shift less than 1° @ 20KHz 

Output section risetime 
600 V/µs 

Power consumption
500 watts ( per channel )

18" deep x 17" wide x 8.5" tall ( 46 x 43 x 22 cm)
per chassis  

36 lbs. ( 16.3 kg ), per chassis, without tubes 

Three year general coverage
One year for output tubes

Atma-Sphere MA-1


Power Supply Boost
V-Cap Copper Foil Teflon® coupling caps
Caddock® resistor package  

Meter Panel finish options

Brushed anodized silver
Brushed anodized gold
Custom finishes available


Jumper plugs for high efficiency speakers - Replaces tube in the voltage amplifier section of Atma-Sphere
power amplifiers, thus reducing gain for high efficiency speakers. Recommended when efficiency of speaker is over 100.


Balanced Interconnects
Balanced phono cables
1 meter, DIN to XLR or RCA with ground post to XLR 

For additional information, audition and pricing, contact our worldwide dealers or our headquarters.


1742 Selby Avenue
St. Paul, MN 55104


Tel : +1 651-690-2246