Atma-Sphere MA-1 MK3.1 amplifier

Atma-Sphere MA-1 MK3.1 amplifier is recipient of Golden Ear Award from The Absolute Sound in year 2000. The MA-1 has enjoyed an enviable reputation. Now the Mk.3.1 series builds on the advances of our decades-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 new, rugged, non-magnetic chassis features classic looks with superior layout. Setup of the amplifier is simple with automatic bias. The controls and switches are ergonomic without sacrificing performance.

The MA-1 Mk.3.1 is easy to live with. It is easy on tubes and and tube failure is inconsequential. Despite its extreme performance, the MA-1 is known for remarkable ease of setup, ease of operation and day to day consistency. Atma-Sphere’s new custom wire, V-Cap Teflon coupling caps, custom resistors and the features below are why Atma-Sphere amplifiers are the best worldwide, regardless of cost.

FEATURES

• Balanced Differential Design®
• All triode
• No tube matching
• Class-A operation
• Automatic bias
• Patented Circlotronic® Output transformerless operation (OTL)
• Handwired mono construction
• Easily monostrapped for more power
• Standby switch for long output tube life
• Simple, reliable circuit –one stage of gain
• XLR and RCA input connectors
• V-Cap Teflon coupling capacitors- standard
• Custom built wire and resistors
• Precision components used throughout
• “Star” ground circuit
• Neo-classic chassis is available in custom finishes
• Three-year warranty – One year on tubes

OPTIONS

• Caddock Resistor package $1100
• Power Supply Boost (uses custom built filter caps for MA-2) $2400
• Meter panel color options: brushed anodized gold, black or silver, no charge

SPECIFICATIONS

• 140 watts/channel into 8 ohm load/135 watts into 4 ohm load
• Power bandwidth: 2 Hz – 100 kHz within 1/2 db
• Frequency response (1 watt): 1 Hz – 200 kHz within 1/2 db
• IM distortion: less than .05% at full power
• THD: nominally less than 0.5% with proper setup
• 20 Hz Square Wave Tilt: unmeasurable
• Phase shift: less than 1 degree @ 20 kHz
• Power supply storage: 600 Joules/chassis
• Input impedance: 100K single-ended, 200K balanced
• Output section risetime: 600V/micro-second
• Output Impedance ~2.3 Ohms (power method standard measurement)
• Power consumption: 500 watts/chassis
• Tube complement: 14 6AS7s and 5 6SN7s per channel
• Weight: 36 lbs./chassis
• Dimensions 18″ L x 17″ W x 8.5″ H