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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

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

Atma-Sphere

MA-1

Reviews & Awards

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

AudioReview.com
Various, user submitted

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

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

Input
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 ) 

Gain
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 )   

Distortion
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 )

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

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

Warranty
Three year general coverage
One year for output tubes

Atma-Sphere MA-1

Options

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

Meter Panel finish options

Black
Brushed anodized silver
Brushed anodized gold
Custom finishes available

Accessories

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.

Cables

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.

Address

Atma-Sphere
1742 Selby Avenue
St. Paul, MN 55104
USA

Contact

Email:
ralph@atma-sphere.com
Tel : +1 651-690-2246