Pass Labs X350.5 specification

Speaker Interface

Interconnects and Speaker Cables

X350.5 Owners Manual

The Pass Laboratories™ X350.5 is optimized for loads nominally rated at 4 ohms and above. You can run the amplifiers into a lower nominal impedance without difficulty, and we are not aware of a speaker on the market that presents unusual difficulty with these amplifiers.

The X.5 series amplifiers do not care particularly about the reactivity of the load. Reactive loads typically will have slightly less distortion at a given voltage/current level than resistive loads, but will make the amplifier run a little hotter. The X.5 circuit was designed to be quite happy driving electrostatic and other difficult speakers.

When driving transformer-coupled loads directly, as in some elec- trostatic and ribbon designs, some attention must be paid to the DC character of the situation. If the transformer primary is being driven raw with no protection from DC and your source has DC voltage, or in cases where the small offset of the power amplifier is still too much, you may create distortion in the transformer and get less than optimal performance from it. Generally this is not the case with transformer- coupled loudspeakers, but it does occasionally surface. In these cases, take special care that the source does not contain a differential DC component, and confirm the differential DC offset of the pre-ampli- fier is sufficiently low. This differential voltage is easily adjusted by a qualified technician armed with the appropriate service documents.

We have a general recommendation about interconnects, which is that they should cost less than the amplifier, and be flexible enough to work with. 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 or ground loops. It is also not sensitive to radio frequency pickup, which allows some flexibility in choosing source interconnects without shields, though shields are always in good taste.

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 gift us a couple hundred meters.

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

We have found that about 90 per cent of bad sounding cables are in reality bad sounding connections, and we recommend that special at-

X350.5 specifications

The Pass Labs X350.5 is a high-performance power amplifier renowned for its exceptional sound quality and cutting-edge technology. Designed by acclaimed audio engineer Nelson Pass, the X350.5 embodies a commitment to delivering a rich and immersive listening experience, making it a favorite among audiophiles and music enthusiasts alike.

One of the standout features of the X350.5 is its Class A/B amplifier design. This brilliant configuration allows for a balance between high efficiency and class A sound reproduction. The amplifier operates in pure Class A mode for lower power demands, providing a pristine audio signal with reduced distortion. When power requirements increase, it seamlessly transitions to Class AB operation, ensuring consistent performance across a wide range of playback levels.

The X350.5 is rated for 350 watts per channel into 8 ohms, which provides ample power to drive even the most demanding loudspeakers. Its ability to deliver 700 watts into 4 ohms ensures that dynamic peaks in music are handled effortlessly, preserving the integrity of the audio signal. This capability is further enhanced by the amplifier’s robust power supply, which features a substantial toroidal transformer and large reservoir capacitors, ensuring adequate power is always available for high transient demands.

Another defining characteristic of the X350.5 is its innovative thermal management system. The amplifier utilizes a patented biased circuit that keeps the output devices within an optimal temperature range, enhancing longevity and reliability while maintaining sound performance. The unique design also incorporates oversized heat sinks that dissipate heat efficiently, allowing the amplifier to operate cool under heavy loads.

The X350.5 features a balanced and unbalanced input configuration, making it versatile enough to integrate seamlessly into various audio setups. The careful attention to detail in the internal component quality and layout reflects Pass Labs’ dedication to minimizing noise and maximizing signal integrity.

With its sophisticated design, the Pass Labs X350.5 offers audiophiles an unrivaled listening experience, characterized by rich timbre, precise imaging, and expansive soundstage. This amplifier is not merely a piece of equipment; it's an invitation to experience music as it was meant to be heard, bringing recordings to life in the comfort of one's home. The X350.5 exemplifies Pass Labs' philosophy of combining art and precision in the pursuit of audio excellence.