XA200.5 Owner’s Manual

Nelson Pass has been designing audio electronics since about 1971, first with ESS (remember Heil transformers?), and then forming a new company, Threshold in 1975. Threshold pioneered the design of high power Class A power amplifiers and later, high power amplifiers using only local feedback (the Stasis series).

Pass sold Threshold and created Pass Laboratories in 1991, where he concentrated first on elevating single-ended Class A power amplifiers to new power levels and performance, the Aleph series.

Along the way he found the time to design successful lines of amplifiers for such companies as Adcom and Nakamichi, and has contributed approximately 60 designs (so far) to the public “Do-It- Yourself ” hobbyist community.

Over the years, Nelson Pass has made power, simplicity, and performance his design signature. The hardware tends to run heavy and hot, but elicits high performance and reliability from simple circuits with little or no negative feedback..

In 1998 Pass Labs released the X series of audio power amplifiers, based on the “SuperSymmetric” topology (U.S. Patent #5,376,899) which elicits high power and performance from simple circuits with minimal feedback.

The first X amplifier, the X1000 was intended as the premier example of the power of this principle, delivering 1000 watts rms into 8 ohms at low distortion. By itself of course, this is no miracle, but you have to consider that products with comparable performance have complicated circuits with as many as nine consecutive gain stages and lots and lots of negative feedback. The X1000 had only two stages and used only local feedback.

The difference was the unique balanced circuit topology in which circuit errors are replicated at both output terminals so as to cancel and disappear across the loudspeaker terminals. The high quality of the sound reflects both the low distortion and simplicity of the gain path.

The SuperSymmetric circuit consists of two identical matched circuits arranged like the wings of a butterfly, showing symmetry from left to right, and operating balanced to the loudspeaker. The amplified signal appears with opposing phase across the loudspeaker. Most of the distortion and noise appears in phase across the loudspeaker, and is not seen.

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Pass Labs XA200.5 owner manual
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XA200.5 specifications

The Pass Labs XA200.5 is a distinguished power amplifier that epitomizes high-end audio engineering, renowned for its exceptional sound quality and performance. Designed to cater to audiophiles and serious music lovers, the XA200.5 combines innovative technologies with elegant craftsmanship to deliver an unparalleled listening experience.

At the core of the XA200.5 is its Class A topology, which is celebrated for its ability to produce warm, rich sound with minimal distortion. The amplifier is capable of delivering 200 watts of power into an 8-ohm load, and it can double that output for 4-ohm loads, making it suitable for driving a wide range of loudspeakers, from modest bookshelf models to demanding floor-standing designs. This impressive power reserve ensures that the XA200.5 can handle dynamic peaks effortlessly, providing a sense of authority and control over the music.

One of the standout features of the XA200.5 is its proprietary "current source" design. This technology allows the amplifier to deliver musical dynamics with precision while maintaining a linear response across the audio spectrum. Pass Labs emphasizes the importance of low signal distortion, and the XA200.5 achieves this through meticulous engineering, including high-quality components and a robust power supply. The power supply not only supports the high current demands of the amplifier but also contributes to the overall stability and performance of the unit.

The build quality of the XA200.5 is exceptional, with a substantial chassis constructed from high-grade aluminum. This not only adds to its aesthetic appeal but also enhances durability and minimizes resonance, ensuring that the internal components function optimally. The amplifier features a distinctive design with large heat sinks that facilitate efficient thermal management, keeping the unit cool even during extended playback sessions.

Another notable aspect of the XA200.5 is its single-ended input configuration, which is designed to enhance musicality. This input sensitivity allows for direct connection to source components without the need for a preamplifier, ensuring a pure signal path. Additionally, the amplifier includes balanced input options for those who prefer using balanced connections.

In summary, the Pass Labs XA200.5 is a powerhouse of an amplifier that beautifully marries technological innovation and elegant design. With its Class A operation, proprietary current source technology, and exceptional build quality, the XA200.5 delivers a remarkable audio experience that is both impactful and refined, making it a top choice for discerning audiophiles.
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