The DMA-200S Series 2 High Resolution Amplifier


Thirty years ago Spectral introduced the DMA-200 Class A reference power amplifier. The high-speed, high powered DMA-200 was a new kind of audio amplifier inspired by high technology innovations and instrumentation design in Silicon Valley. A radically different approach to amplifier design, the DMA-200 introduced the first ultra-wideband, high power signal response in the audio industry and was an immediate worldwide success, changing the way serious designers defined amplifier performance. Today, the new DMA-200S builds on the achievement of the original DMA-200 and illustrates Spectral’s insistence on state-of-the-art signal resolution, musicality and high value. 

As the foundation of the Spectral amplifier family, the DMA-200S represents striking progress in the development of an ideal power amplifier for high performance music systems. Drawing on the many design advances developed for Spectral’s ambitious DMA-360 S2 Monaural Reference Amplifier, the performance and technology of the DMA-200S are fundamentally superior to that of conventional SS and tube power amplifiers, achieving significantly lower distortion levels and radically faster signal response. 

The uncompromising high-speed amplifier topology of our DMA-360 S2 Reference Amplifier forms the basis for the remarkable DMA-200S. This new generation topology features innovative input, gain and output driver stages based on a new family of premium discrete silicon devices. The pure class A driver and gain sections now operate up to ten times faster than previous Spectral designs and offer dramatic improvement in transient resolution and an ultra-low noise floor. Amplifier settling and recovery are perfect. The result is immersive sonics of extraordinary purity and detail which emerge from an absolutely uncompressed soundfield, free of artifact or fatigue. 

From much listening and design experimentation, Spectral has consistently pioneered component systems having fast settling, high-speed circuit architecture. These have invariably outperformed more traditional often cumbersome high-end design methods to achieve superlative detail, soundstaging and listener involvement. Indeed, test methodology simulating music waveforms and hearing acuity confirm that quickness of response and rapid signal extinction when reproducing complex dynamics are mandatory for accurate music reproduction. Only then can one preserve instantaneous waveform accuracy to prevent cover-up of delicate musical signals by previous events. Construction and performance of the Spectral DMA-200S Reference Amplifier for this demanding criterion and resulting sonic resolution are unmatched among contemporary high-end amplifier designs.



Unparalleled Resolution, Unprecedented Control 

The very high-speed launch and high current reserves of the DMA-200S are possible with the use of Spectral’s proprietary “Focused Array” construction. This breakthrough topology aligns high-current vertical FET output devices for rapid, pistonic signal launch. The output section is comprised of eight individual V-FET amplifier modules paralleled to achieve a minimum 180 watt RMS /per channel with 60 amp capability. With this “Focused Array” arrangement of parallel FET amplifiers, full rated power is delivered with total load stability at an unprecedented 1 MHz. Like the renowned DMA-360 Reference Amplifier, the DMA-200S utilizes Spectral’s unique “Focused Array” output section design with powerful ultra-fast Mega FET devices. Each device, having vacuum tube like operating character, is energized from its own dedicated high energy storage capacitor, rectifier, and individually powered from an isolated ultra-low coupled transformer winding. Individual teflon bias trimmers are used to calibrate each output device separately. Groups of these individual output device / power supply circuits utilize field folding construction and electronic shielding to further impede propagation of stray interference. The resulting “Focused Array” of individual isolated output sections performs as one with virtually no cross-coupling and energy storage artifacts reflecting between output devices. During extreme program dynamics, this arrangement can launch an instantaneous high current drive of over 60 amps per channel to the most sophisticated loudspeakers with assured precision waveform tracing. Gone are performance damaging magnetic and electrical field propagation problems of conventional multiple device power amplifiers. Without stray radiation, critical small signal paths within the DMA-200S and other sound system components can perform with lowest possible distortion and settle to signal extinction in microseconds. Hence, the DMA-200S works with power and speed yet behaves inert to other electronic parts of the system. Reproduction is highly articulate and resolving yet has all the powerful unlimited character of the finest very high power amplifier designs due to its superb overload and ultra-fast recovery characteristics.















The Power Vault  

The Focused Power output section of the DMA-200S is only one of the many Spectral innovations designed to create the ultimate in amplifier control and resolution. A unique transformer architecture supports the critical requirements for lowest noise and high power capability of the powered output section array. In traditional high-end power amplifiers, output transformers are located away from active amplifier circuitry for purposes of noise isolation and construction ease. This virtually universal method extracts a significant sonic price, however, because of the speed and regulation losses which are imposed by the long power supply wiring harness. In addition, the EMI and noise which radiate from the supply harness invariably contaminate sensitive low level circuitry by noise modulating the musical signal. Spectral engineers have long recognized the problems associated with power supply noise contamination and have proposed a unique solution in the DMA-200S High Resolution Amplifier. The Power Vault electromagnetic field containment system virtually eliminates EMI radiation to the amplifier signal path circuitry as well as power and regulation losses through the traditional power supply harness. 

The architecture starts with Spectral's elaborate high performance custom power supply transformers. These unique designs are the result of years of research and development to maximize isolation and regulation. Each transformer features individually isolated windings to support each individual output transistor in the amplifier output section, a premium technique shared only with the Spectral DMA-360 Reference Amplifier. The twin power transformers are mounted between massive machined mounting plates for damping and resonance control. The combined 38 lb. Transformer structure is then mounted on a constrained rubber floating suspension system employing multiple compliances similar to a fine turntable suspension. The finished transformer assembly is then suspended inside an EMI, RFI tight welded aluminum containment box located directly beneath the DMA-200S output section. The resulting transformer Power Vault containment system results in an uncompromising solution to the universal power supply noise problem. The high-current power transformers are now intimately sited next to their own high-current output devices with extraordinary noise isolation. The high-speed driver circuitry of the DMA-200S operates in a pristine environment free of the noise radiation and phantom signals which plague other power amplifiers. Dynamic range limitations are removed with a sonic clarity and quietude which is palpable.


Premium Discrete High Speed Circuitry 

Small signal circuitry in the DMA-200S is based on Spectral's proven discrete circuit multiple cascode, double push-pull FET technology. Premium silicon array construction, similar to circuitry in the DMA-360 Reference Amplifier, is applied to the DMA-200S to achieve enormous internal dynamic range capability. This reserve is linear class A with many times greater dynamic capability than program demands. It allows high current drive for quick controlled response from the very large output FET's as well as isolation from their internal electronic activity. Unhindered by interferences and slow cumbersome response of conventional practice, these parts operate with unyielding control and exacting precision. Reproduction is absolutely pure, effortless and highly focused and holographic.

Audio amplification paths through the DMA-200S are direct, inherently linear and simple. These minimalist configurations have always sounded and measured the best but normally become ponderous and overburdened when protection and support functions are added. The DMA-200S takes a different route to solve the sonic problems of amplifier protection circuitry. To maintain the pristine signal path, a sophisticated analog computing ancillary system is thermal and optocoupled within the amplifier. This “hands off” operational management system observes device loading and power dissipation as well as speaker damaging out of range signals. It takes control without circuitous cross interfering connections to electronics in the signal path, leaving the musical signal absolutely pure and totally untouched.











Power and Precision In A Unique Marriage

Improvements in high-current FET technology, high-speed amplifier topologies and new protection systems are combined in the DMA-200S High Resolution amplifier to successfully advance the art of amplifier design. Until now, amplifiers could not offer both powerful speaker control capability and the sonic transparency and life possible only with high-speed, fast settling circuitry. Breakthrough circuits backed by Spectral experience have now brought together the necessary combination of speed, accuracy, control and stealth. The DMA-200S High Resolution Amplifier advances the Spectral tradition for uncompromising musical resolution and sonic holography.

The Reference Amplifier For The Rest of Us 

The Spectral DMA-200S Reference Amplifier is a ‘game changer’ just as its revolutionary predecessor was decades ago. With its extreme ultra-low distortion and extraordinary signal response courtesy of the benchmark DMA-360 S2, the DMA-200S sets a very high standard indeed. Today’s DMA-200S distills the essence of what Spectral engineers have discovered over decades of painstaking engineering research in pursuit of ultimate amplifier design. The DMA-200S is also eloquent proof that state-of-the-art performance and ultimate refinement need not cost a kings ransom. Although of moderate cost, the DMA-200S offers uncompromising sonic sophistication and drive precision for the most critical of music system applications. The DMA-200S is the reference amplifier for the rest of us.


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