PASS LABS CLASS A

SOLID STATE CLASS A AMPLIFIERS

"These are Pass Laboratories ultimate expression of Power Amplifiers, the perfect blend of science and visceral emotion. If there’s a more emotionally satisfying amplifier anywhere, we’re not aware of it"

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BY NELSON PASS - MADE IN THE USA

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Xs300

The Xs series monoblock power amplifiers represent the reference-quality, state-of-art amplifiers from Pass Laboratories. Through years of "spare no effort" endeavor, they represent the true pinnacle of music reproduction. The Xs 300 delivers 300 watts, employs separate power supply and amplifier chassis' for lower noise and utilizes higher-power constant-current source. Single-ended bias current not only lowers distortion, but facilitates better control of its harmonic structure, tweaked and optimized through endless listening tests for your musical pleasure.

Xs 300 SPECIFICATIONS

Class - A

Type - Mono

Gain (dB) - 26

Inputs - XLR / RCA

Power /ch (8 ohm) - 300W

No Output devices (/ch) - 112

Power Consumption (Watts) - 900

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 2

Dimensions / in. (WxDxH) - 19 x 27.5 x 11 x 2

Unit Weight (LBS) -  134 / 172

$ 85,000

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Xs150

Like the Xs 300, this amplifier was developed through constant and thorough innovation.

 

After years of SIT device experimentation, followed by deployment in Nelson's First Watt designs, circuit modification captured the unique tube-like sonic footprint of SITs from much higher-output MOSFET devices used in the Xs series.

 

The result is unparalleled, fatigue-free listening enjoyment

Xs 150 SPECIFICATIONS

Class - A

Type - Mono

Gain (dB) - 26

Inputs - XLR / RCA

Power /ch (8 ohm) - 150W

No Output devices (/ch) - 112

Power Consumption (Watts) - 700

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 2

Dimensions / in. (WxDxH) - 19 x 21.5 x 11 x 2

Unit Weight (LBS) -  102 / 132

$ 65,000

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XA200.8

Are fabulous-sounding 400-watt-plus per channel class-A peaks attainable without loss of the musical detail or audible meltdown? Yes, through repeated listening tests and continual technical innovation that push performance standards, the XA200.8 achieves what most amplifiers can only dream about.

 

Even for the most demanding, complex musical passages in larger rooms at high sound pressure levels, this model offers headroom to spare

XA200.8 SPECIFICATIONS

Class - A

Type - Mono

Gain (dB) - 26

Inputs - XLR / RCA

Power /ch (8 ohm) - 200W

No Output devices (/ch) - 72

Power Consumption (Watts) - 760

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 1

Dimensions / in. (WxDxH) - 19 x 27.5 x 11

Unit Weight (LBS) -  157

$ 42,000

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XA160.8

More of just about everything: 72 output power-MOSFETs, higher input impedance, higher capacity power supply and the ability to deliver over 320 watts per channel in class A with greater dampening. The 160.8's deliver power and finesse in spades. Voices take on shape and depth, piano notes arrive with full acoustic integrity and the rest of the rhythm section is delivered with both powerful attack and holographic sustain.

 

The effortless conveyance of musicality and realism must be heard to be believed.

XA160.8 SPECIFICATIONS

Class - A

Type - Mono

Gain (dB) - 26

Inputs - XLR / RCA

Power /ch (8 ohm) - 160W

No Output devices (/ch) - 72

Power Consumption (Watts) - 580

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 1

Dimensions / in. (WxDxH) - 19 x 21.5 x 11

Unit Weight (LBS) -  123

$ 27,300

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XA100.8

The middle sibling of the XA.8 series, the XA100.8's realize a muscular yet highly refined sonic profile, and features single-ended and balanced inputs, Furutech five-way binding posts and a convenient ground terminal for safe subwoofer connection. Improved constant-current sourcing, precise voltage references and current-feedback all represent new benchmarks in state-of-art amplifier design. The result is a larger, more realistic soundstage, sharper transient response and the prized ability to reach concert-hall dynamics and realism without strain..

XA100.8 SPECIFICATIONS

Class - A

Type - Mono

Gain (dB) - 26

Inputs - XLR / RCA

Power /ch (8 ohm) - 100W

No Output devices (/ch) - 56

Power Consumption (Watts) - 420

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 1

Dimensions / in. (WxDxH) - 19 x 21.5 x 9

Unit Weight (LBS) -  99

$ 20,300

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XA60.8

Offering all the sonic benefits of the .8 amplifier line, a pair of XA60.8's also grace the listener with mono-block performance: dedicated power supplies for each channel, dedicated circuitry for each channel and dedicated chassis' for each channel offer a cleaner, better defined image and soundstage.

 

Beautiful to the ears and eyes, this model achieves levels of focus and intimacy normally associated with the finest tube amplifiers. The XA60.8's do all of this while providing greater control and power.

XA60.8 SPECIFICATIONS

Class - A

Type - Mono

Gain (dB) - 26

Inputs - XLR / RCA

Power /ch (8 ohm) - 60W

No Output devices (/ch) - 40

Power Consumption (Watts) - 400

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 1

Dimensions / in. (WxDxH) - 19 x 21.25 x 7.5

Unit Weight (LBS) -  88

$ 13,500

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XA30.8

An exceptional stereo power amplifier on many levels -- high-biased MOSFETs providing higher-power class A operation, direct-coupled front-end circuitry for exceptionally high stability and larger, more robust heats sinks similar to those of the larger .8 amplifiers.

 

The list goes on, but listening may tell you the XA30.8 represents a value high-point -- quite possibly your particular optimal balance between performance and cost.

XA30.8 SPECIFICATIONS

Class - A

Type - Stereo

Gain (dB) - 26

Inputs - XLR / RCA

Power /ch (8 ohm) - 30W

No Output devices (/ch) - 40

Power Consumption (Watts) - 400

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 1

Dimensions / in. (WxDxH) - 19 x 21.25 x 7.5

Unit Weight (LBS) -  88

$ 6,800

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XA25

The new XA25 offers great sound at slightly lower power, without frills, at a lower price. It embodies new components and innovative circuits coupled with the best elements of the previous generation.

 

Degeneration, “the other form of feedback”, has been eliminated. The output stage consists of a single pair of 800 watt new generation output transistors operating push-pull Class A. The result is faster, lower distortion, lower noise, higher damping and larger Class A operating envelope into low impedance loudspeakers, all in a simple 3 stage circuit with total of three pair of push-pull gain transistors.

XA25 SPECIFICATIONS

Class - A

Type - Stereo

Gain (dB) - 20

Inputs - RCA

Power /ch (8 ohm) - 25W

No Output devices (/ch) - 4

Power Consumption (Watts) - 240

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 1

Dimensions / in. (WxDxH) - 17 x 17.25 x 6

Unit Weight (LBS) -  48.5

$ 4,900

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INT25

At Pass Labs we build Fet amplifiers with excessive output stages, huge heat sinks and massive power supplies. We use the highest quality components in simple linear topologies, assembled and tested with care and subtlety. They measure well, sound great, and are reliable. Twenty plus years of ongoing innovation have kept the X and XA amplifiers at the forefront of high-end audio.

 

The INT-25 embodies all this and less. A smaller stereo Class A amplifier at a lower price, it takes advantage of the lower power requirements to have simpler single-ended circuitry and fewer parts in the signal path. This also allows elimination of degeneration, “that other negative feedback”.

Simpler and fewer gain stages improves speed and stability. Lower voltages means the ability to run gain devices at higher bias currents, more deeply into Class A. Newer power Fet technology replaces banks of parallel small transistors with a single pair of industrial devices, each having a 700 watt / 40 amp rating.

 

With no current-hogging issues and a new constant-current bias circuit to compensate for temperature drift, they connect directly to the loudspeaker without ballast resistors for lowest possible distortion and highest damping factor. No degeneration also increases the efficiency and Class A operating current, allowing greater Class A operation into low impedance and reactive loads.

 

The simple front end circuit uses two pairs of our favorite NOS complementary Fets in common-source mode in a current feedback (CFA) configuration. 

 

The preamp section is a simplified single-ended version of the one used in the INT-60 and INT-250 with three line level inputs and no line level output.

 

Everything done in the signal chain from the microphone to the loudspeaker, forever leaves an indelible mark on the music. The XA25 amplifier section is direct coupled requiring no DC servos or frequency compensation, neither adding too or subtracting from the experience.

 

As with all Pass amplifiers, the technology and construction are strictly in the service of the listening experience. The INT-25 measures superbly, but its subjective qualities are most special. In an industry where products with great specs are often found to be dry and boring, this amplifier breathes new life into the music.

INT25 SPECIFICATIONS

Class - A

Type - Stereo

Gain (dB) - 29 / 35

Inputs - 3 x RCA

Power /ch (8 ohm) - 25W

Remote  /  Volume Control 63 x 1db steps

Power Consumption (Watts) - 200

Standby Power Consumption (Watts) - < 1W

Number of Chassis - 1

Dimensions / in. (WxDxH) - 17 x 17.375 x 6

Unit Weight (LBS) -  49

$ 4,900

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