how to make a site

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

Optional Features

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

Meter Panel finish options

Gray hammertone
Brushed anodized black
Brushed anodized silver
Brushed anodized gold
Custom finishes available upon request

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 informations, 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