X1 Owner’s Manual

If your signal source is unbalanced, input will always occur through the RCA input connector. Inputs 1 and 2 give you a choice or either single ended or balanced inputs. When single-ended inputs are used on input 1 and input 2, a shorting plug, which is provided, should be inserted between XLR pins 1 and 3 of the associated connector. This plug shorts the negative input to ground thus optimizing the input connection. You can run the X-1 without this shorting plug, but performance will not be ideal. (NOTE: inputs 3 & 4 are single ended only and do not have XLR’s associated with them.) You are free to use any combination of balanced and unbalanced connections with the X1. The unbalanced input impedance of the preamplifier is 33 kOhms. In balanced mode, the input impedance is higher, with a differential impedance of at least 66 kOhms.

Next to the inputs on the rear panel, the preamplifier offers tape inputs through both XLR and RCA connectors. This output is a direct connection to inputs 1, 2, 3, and 4 when they are selected from the front panel. Input 5 (TAPE IN) is deliberately not available through the tape output connection. Input 5 is designated for use with a tape recorder if you have one, and we have arranged that it will not place its output on the tape out, which will prevent you from accidentally creating a feedback connection with your tape machine.

The main outputs are located at the left-hand side (viewed from the rear) of the rear panel, two male XLR connectors, and two RCA connectors, “R” (right) and “L” (left). The RCA connectors ground is in parallel with pin 1 of the XLR outputs and the RCA hot is fed from an independent summing junction that maximizes the X circuit benefits. The RCA, single-ended, outputs are buffered from the balanced outputs. You may use both the single ended and balanced outputs at the same time. On the XLR, pin 1 is ground, pin 2 is positive, and pin 3 is negative.

The X1 takes maximal advantage of four identical gain paths (two identical paths per channel) very much unlike the typical two gain path (one signal path per channel) pre-amplifier you may be familiar with. Almost without exception traditional audio pre-amplifiers, unlike their science and industry counterparts, have maintained single signal path per channel (two identical paths in a stereo pair).

In order to manage balanced signals these two gain path pre- amplifiers must utilize phase combining networks to process incoming signals and subsequently drive outputs via phase splitting circuits to re-establish a quasi-balanced signal. This manipulation of signal typically adds additional gain stages and degrades the inherent

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Pass Labs X1 owner manual
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X1 specifications

Pass Labs X1 is a high-end preamplifier that embodies the very essence of cutting-edge audio engineering, combining advanced technologies with superior craftsmanship to deliver an exceptional sonic experience. Known for its neutral and transparent sound signature, the X1 is designed to serve as the heart of a high-fidelity audio system, providing precise control over volume and input selection while ensuring signal integrity is maintained.

One of the defining features of the Pass Labs X1 is its fully differential architecture. This design not only enhances noise rejection but also minimizes distortion, resulting in a clean and accurate reproduction of music. The X1 employs a direct-coupled topology, allowing for a wider bandwidth and increased dynamic range, essential for capturing the subtleties of any audio performance.

The X1 also integrates a sophisticated power supply, utilizing separate transformer windings for the analog and digital circuits. This isolation reduces cross-contamination between sections, which is crucial for maintaining the integrity of the audio signal. The power supply is supplemented by high-quality capacitors and regulators, ensuring that the preamplifier operates with stable voltage and low noise.

In terms of connectivity, the Pass Labs X1 offers a comprehensive array of inputs and outputs, including balanced XLR and unbalanced RCA connections. This versatility allows it to interface seamlessly with a variety of sources and amplifiers, making the X1 suitable for both audiophile and professional environments. Additionally, the preamp features a remote control for added convenience, allowing users to adjust settings from a distance without compromising sound quality.

Another notable characteristic of the Pass Labs X1 is its rugged build quality. Constructed using high-grade materials and meticulously tested, the unit not only looks elegant but is designed to last, providing years of reliable performance.

Ultimately, the Pass Labs X1 is a testament to the brand's commitment to excellence in audio reproduction. Whether used in a dedicated listening room or as part of a professional setup, the X1 delivers a listening experience that is both immersive and true to the original recording, making it an invaluable component for any serious music enthusiast or audio engineer.
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