Interconnects and Speaker Cables

and the energy reserve held in the capacitors will do its job. As a practical matter, it will not make a lot of difference. Just don’t call us up and complain that you only measured 1900 watts in your living room. If you do, we’ll want to know what speakers can take it.

We have a general recommendation about interconnects, which is that they should cost less than the amplifier. We have tried a lot of products and most of them work well, but as a practical matter we cannot make blanket recommendations.

The amplifier is not sensitive to source interconnects. It is also not sensitive to radio frequency pickup, which allows some flexibility in choosing source interconnects without shields.

We prefer speaker cables that are thick and short. Silver and copper are the preferred metals. If you find any cable made of gold, please send me a couple hundred feet.

Fortunately the amplifier is not sensitive to the capacitive/inductive character of some of the specialty speaker cables, so feel free to experiment.

We have found that about 90 per cent of bad sounding cables are really bad connections, and we recommend that special attention be paid to cleanliness of contact surfaces and tight fit.

Speaker cables should be firmly tightened down at the speaker output terminals, but do not use a wrench. They will not withstand 100 foot-lbs of torque. Hand tightening without excessive force is plenty.

Source Interaction

The amplifier does not care what the source impedance is, although its gain will drop a bit with high source impedances. Since we have 30 dB of gain (26 dB in the X350), we can afford to throw a little bit away, since the quality is unaffected. Using a balanced source attenuated through a balanced passive attenuator is perfectly OK, and we often use this approach ourselves to minimize components in the signal path and also to reduce bit loss in CD players with digital volume controls.

The differential input impedance of the amplifier is 22000 ohms, although this drops to 2000 ohms when the amplifier is in stand-by mode. 22000 ohms is not a problem for any balanced source circuit we ever heard of, and will not be a problem for you.

As pointed out elsewhere, this power amplifier is the first ever to truly take advantage of the concept of balanced operation for more than just noise reduction. As such it prefers balanced input symmetry for optimal operation.

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X600, X350, X1000 specifications

Pass Labs is renowned for its high-quality audio amplification equipment, and their amplifiers—like the X350, X1000, and X600—exemplify their commitment to exceptional sound reproduction and advanced engineering. Each model reflects innovative technologies and distinctive characteristics that cater to audiophiles seeking premium performance.

The Pass Labs X350 is a powerhouse that strikes a balance between power and finesse. It is a Class A amplifier, delivering 350 watts per channel into an 8-ohm load, which translates to incredible clarity and dynamic range across a variety of music genres. One of the standout features of the X350 is its use of the innovative Front End Circuitry, which enhances both linearity and low-frequency response. This ensures that the amplifier can handle complex musical passages effortlessly while retaining the natural timbre of instruments. The X350 also employs the renowned "Pure Class A" operation, resulting in minimal distortion and a warm, engaging sound signature that is particularly pleasing for long listening sessions.

In the range, the X1000 takes performance to the next level. With a staggering output of 1000 watts per channel into 8 ohms, it is designed for those who demand uncompromising power. The X1000 features a fully balanced design, providing superior common-mode rejection and eliminating unwanted noise. This model leverages advanced MOSFET technology, allowing for refined audio reproduction without sacrificing power. The robust build quality, including heavy-duty heat sinks, ensures optimal thermal management, which is vital for maintaining performance during extended use.

If you're in search of an amplifier that combines muscular performance with fine detail, the X600 is a noteworthy option. With 600 watts per channel into 8 ohms, this amplifier takes advantage of Pass Labs' patented technology to deliver nuanced sound without harshness. The X600 also incorporates a unique bias system that automatically adjusts based on the demand of the signal, maximizing efficiency and maintaining sound fidelity. This attention to detail helps in preserving the dynamic range and depth of the audio, making it suitable for both critical listening and casual enjoyment.

In summary, Pass Labs’ X350, X1000, and X600 amplifiers are masterpieces of audio engineering. They each showcase unique technologies and features that cater to a wide range of audiophile preferences—from the balanced performance of the X350, the sheer power of the X1000, to the nuanced detail of the X600. Whether for a sophisticated home theater setup or a dedicated stereo system, these amplifiers stand out for their ability to provide immersive listening experiences that are rich, dynamic, and true to the source.