J2 Power Amplifier


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25 watts per channel, Class A amp, dynamic, and impactful sound More details

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The First Watt J2 power amplifier is a masterpiece of audio engineering designed to bring music to life with unparalleled clarity and precision. The J2 is a stereo amplifier that produces 25 watts per channel into 8 ohms, showcasing Pass Labs' renowned Class A topology. Its symmetrical circuitry and high-quality components ensure a pure and transparent sound signature, allowing the nuances of your favorite music to shine through. With its minimalist design, robust build quality, and exceptional performance, the First Watt J2 is a testament to the brand's commitment to creating audio equipment that sets the standard for excellence. Whether driving bookshelf or floor-standing speakers, the J2 delivers an engaging and immersive listening experience for the most discerning audiophiles.

The J2 power amplifier boasts a clean, minimalist design and exceptional measurements. Its warm, relaxed sound profile offers a unique blend of precision and detail without any hint of sterility. When paired with appropriately efficient loudspeakers, the J2 delivers a toe-tapping experience that sets it apart from other solid-state amplifiers.

Dragon Cable Recommendation: we recommend pairing the J2 power amplifier with our award-winning Silver Dragon Interconnects. The Silver Dragon Interconnect is one of our best-selling cables at Moon Audio. Sold in Pairs, it is our top-of-the-line silver conductor-based interconnect. With a braided geometry and amazing shielding, this interconnect is a remarkable solution where noise isolation is key. The Blue Dragon Power Cable is also recommended to provide the cleanest and unbridled power to your high-end amplifier.

The First Watt J2 power amplifier offers a range of features that contribute to its exceptional performance:

  1. Class A Operation: Utilizes pure Class A operation for pristine sound quality and low distortion.
  2. 25 Watts per Channel: Provides 25 watts of power per channel into 8 ohms, suitable for a variety of speakers.
  3. Symmetrical Circuitry: Ensures balanced and accurate audio reproduction, capturing fine musical details.
  4. High-Quality Components: Meticulously selected components contribute to the amplifier's exceptional sound clarity and dynamics.
  5. Minimalist Design: Boasts a clean and minimalist design that reflects Pass Labs' commitment to simplicity and performance.
  6. Warm and Relaxed Sound: Achieves a warm and relaxed sound profile, blending precision and detail without any sterility.
  7. Efficient Loudspeaker Compatibility: Ideal for use with sensibly efficient loudspeakers, providing a toe-tapping and engaging listening experience.
  8. Reliable Performance: The J2 amplifier is designed for reliability and long-term performance, requiring minimal adjustments.
  9. Solid-State Design: Offers the benefits of solid-state amplification, including efficiency, reliability, and stable performance.
  10. Versatile Connectivity: Features both balanced (XLR) and single-ended (RCA) inputs for flexible system integration.
  11. Robust Build Quality: Crafted with attention to detail and high-quality materials for a durable and long-lasting amplifier.
  12. Musicality: The J2 amplifier is known for its musicality, allowing the listener to fully immerse themselves in the nuances of their favorite music.
J2 Simplified

The J2 is a stereo power amplifier that outputs 25 watts per channel. It is designed with a two-stage amplifier circuit that operates in a pure single-ended Class A mode. The J2 also has signal JFET devices forming the input stage, and power JFET devices for the output stage. JFET transistors are renowned for their excellent sound quality and are the standard for low noise and linearity in the industry. You'll find them on the best phono stages, preamps, and power amps on the market.

Technological advancements with Silicon Carbide (SiC) technology have resulted in new power JFET transistors with higher voltage, current, and power capabilities - as high as 1200 volts, 30 amps, and 273 watts. These new JFETS are designed for fast power switching in solar power and electric vehicle applications, but they also have very low distortion which makes them a great options for linear amplifier applications.

For more than a decade, First Watt has been at the forefront of amplifier design, constantly pushing the boundaries with their simple yet high-performance Class A circuits. The introduction of superior transistors like those used in the J2 amplifier has brought significant advancements. These transistors allow for achieving the same distortion performance with reduced feedback, or alternatively, lower distortion levels with the same feedback amount. The J2 amplifier benefits from these improvements, resulting in a better-sounding amplifier compared to its esteemed predecessors. This enhancement in performance is a testament to First Watt's commitment to innovation and continual improvement in audio engineering.

Pass Labs and First Watt

Pass Labs and First Watt were founded by hi-fi legend Nelson Pass. After co-founding and later selling Threshold Audio, Pass began working out of his Auburn, California, home in the early 1990s to develop prototypes of single-ended Class A amplifier designs under the name Pass Labs. Pass Labs quickly became known for its commercially produced Aleph, X, and XA Series amps, and preamps. Pass later started First Watt as a passion project focusing on low-power amps for a niche audiophile audience. Today, Pass splits his time between the two companies, with production happening in Pass Labs' facility in Foresthill, California.


What is the output power rating of the First Watt J2 Power Amplifier?

The First Watt J2 Power Amplifier is rated at 25 Watts per channel into 8 ohms and 13 Watts per channel into 4 ohms. While this may seem modest compared to some higher-powered amplifiers, the J2's focus is on high-quality, low-power amplification for efficient and detailed sound reproduction. It is designed to excel with high-efficiency speakers and offers a unique sonic signature prized by audiophiles seeking clarity and musicality.

What makes the First Watt J2 Power Amplifier different from traditional amplifiers?

The First Watt J2 is a class-A, single-ended amplifier known for its unique design philosophy. Unlike many traditional amplifiers, the J2 operates in pure class A, delivering its full power output at all times. This design choice contributes to its warm, natural sound signature and ability to maintain sonic purity even at low volumes. The J2 is designed to be simple, with a minimalist approach to circuitry that prioritizes audio quality over features.

Can the First Watt J2 Power Amplifier drive difficult speaker loads?

While the First Watt J2 is not intended for driving highly inefficient or extremely low-impedance speakers, it is capable of driving a wide range of speaker loads effectively. It pairs particularly well with high-efficiency speakers that benefit from its low-power, high-quality amplification. The J2's 25 Watts per channel into 8 ohms is ample for many audiophile-grade speakers, providing an engaging and detailed listening experience.

Does the First Watt J2 require any special setup or maintenance?

The First Watt J2 Power Amplifier is designed to be straightforward to set up and operate. It does not require bias adjustments or regular maintenance beyond typical care for audio equipment. Users should ensure proper ventilation for optimal performance, as the J2 operates in class A, which can generate some heat. As with any amplifier, it is recommended to provide adequate space for ventilation and to follow the manufacturer's guidelines for safe operation.

Who is Nelson Pass?

Nelson Pass, the man behind Pass Labs and First Watt, has been designing and building amplifiers for decades. His early passion, however, was speakers; at age 14, he started assembling loudspeakers. As a college student studying physics at the University of California-Davis, he co-founded a speaker company called PMA. He also worked for ESS, where he designed crossovers and enclosures. After college, with his interest having shifted toward amplifiers, Pass co-founded Threshold Electronics (now Threshold Audio). His achievements during the Threshold years include developing the first dynamically biased Class A amplifier circuit; developing a fully cascode audio power amplifier; and developing the STASIS stereo preamplifier and power amplifier. During the 1980s, Pass designed the Adcom GFA-555 amplifier. Later, after selling Threshold, he started Pass Labs in 1991 and First Watt in 1997. Pass holds several patents related to audio circuits.

How did Pass Labs make its name?

Pass Labs helped popularize solid-state, Class A power amplifiers. Pass Labs' first product, the Aleph 0 amplifier, operated as single-ended Class A up to its 70 watt rating and in push pull Class A at higher wattage. The Aleph series of amplifiers, some of the first solid-state amps that were said to be "tube-like" in sound, operated pure class A and contained internal circuitry using MOSFETs. The Aleph amplifiers had a unique appearance, a cube with heat sinks on all four sides, a solution to the heat generated by the class-A design. This can be attributed primarily to the specific MOSFETs used and the minimum number of gain stages that were implemented in the design. Pass Labs also developed the Super-Symmetry™ ("Su-Sy") circuit, which achieves exceptionally low distortion and noise levels. In 1998, Pass Labs released the X1000, the first amplifier using the patented SuperSymmetric™ topology. The X1000 achieved 1000 watts with high performance, local feedback and only two gain stages: a cascoded differential pair of transistors and a large bank of complementary output followers. This groundbreaking design informed all subsequent Pass Labs amplifiers.

What else does Pass Labs make?

In 2002, Pass Labs unveiled the first XA amplifiers, combining the X and Aleph topologies into balanced single-ended Class A amplifiers with many of the characteristics of both the X and Aleph series. The current Pass Labs lineup includes Class A amps (XA and Xs Series), Class AB amps (.8 Series), line preamps (Xs and XP Series), phono preamps (Xs and XP Series), integrated amps (INT Series), and one headphone amp.

What is the relationship between Pass Labs and First Watt?

When he started Pass Labs, Pass did everything out of his home. In 1997, having outgrown the space, Pass Labs moved into commercial space in Foresthill, California. When Pass started First Watt, it was a "kitchen table" venture, with work once again happening in his home. In 2016, with production demands not leaving him enough time to pursue the vast array of yet-to-be-designed amps, Nelson handed the business end of First Watt over to Pass Labs. Pass Labs took over the building of First Watt amplifiers as well as marketing and distribution. There's a synergy between the two operations, in that Pass Labs gets to gather up some of the more interesting First Watt finds and repurpose them as more commercially viable designs. Today, Pass splits his time between First Watt and Pass Laboratories.


@ 1 watt .025%
Input Impedance
100 Kohm
Balanced input CMRR
-60 dB @ 1 Khz
20 dB
Input Sensitivity
280 mV = 1 watt, 1.4 V = rated power
Damping Factor
Output power 8 ohms
30 watts @ 1% THD, 1KHz
Output power 4 ohms
15 watts @ 1% THD, 1 KHz
Frequency response
- 1 dB @ 4 Hz, 100 KHz
100 uV unweighted, 20-20 KHz
Power consumption
200 watts
3AG slow blow type - 2.5 Amp for 120VAC 1.25 Amp for 240 VAC
Parts and labor for 3 years, not covering shipping costs or consequential damages