Atma-Sphere Music Amplifier MA-3

Atma-Sphere Music Amplifier MA-3is a project Atma-Sphere began in 1998 at the behest of one or its customers. It was 7 years in design; 15 chassis and 7 circuit designs were explored in depth. The idea behind the project is to build a larger version of Atma-Sphere amplifiers than the world has seen before, while at the same time keeping it easy to live with.

One of the biggest problems with amplifiers of this much power output is performance. Tube amplifiers are traditionally best sounding in low power embodiments and high power tube amplifiers often have such poor bandwidth that credulity is strained to call them high fidelity! Transistor amplifiers regardless of price retain the artifact that continues to identify them as transistor amplifiers to the casual listener, regardless of power or cost.

So there is clearly a dreadful need for an amplifier that can actually make serious power yet remain utterly musical. Fortunately, our OTL technology is well suited to the task since we are not limited by issues that plague conventional amplifier designs. At last it is possible to build a truly high power amplifier that is all-tube and has wide bandwidth at the same time. No transformer-coupled amplifier can produce 200, yet alone 400 watts and get it right at every audio frequency; the MA-3 makes 500 watts easily, without electronic artifacts: a high power amplifier that is actually musical.

The MA-3 has all of the features as our other models, plus a few not seen in any amplifier ever produced before. It is class A, all triode, and fully differential, with Atma-Sphere’s patented direct-coupled output circuit. There is only a single gain stage in the amp, so the signal path remains very direct, a feature unknown in amps of this class. Construction is point to point handwired with our custom wire.

What’s new are several features that make the amp very easy to own and operate: There is a built-in on-the-fly tube tester, allowing one to test (and if desired, match) the power tubes in circuit with ease. The output power can be varied, by turning output tubes banks on and off. One can operate the amp on 1/3, 2/3 or all of the output tubes. This saves on the life of tubes and is a useful tool for managing the heat output. Even at lower power levels, the MA-3 retains the innate musical character that defines it as state-of-the-art.

Bias and DC Offset functions are automated. Meters are supplied to monitor the tubes, output power and other features. The amplifier power supply has a built-in AC line processor that regulates the AC line. Line voltage has virtually no effect on the MA-3- it will make full power even if the line voltage is only 100 Volts.

Meters functions include: VU level, tube condition, Bias and DC Offset status and automatic AC line voltage condition. The amp is built on four chassis. The amp unit can be stacked on the power supply unit (as seen above) or operated side by side. Dual speaker posts are used for more flexible operation. Other features are standard per our other amplifiers:

SPECIFICATIONS

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