TONEAudio Magazine
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<p><strong><a rel="attachment wp-att-12495" href="http://www.tonepublications.com/review/first-watt-j2-power-amplifier/attachment/1-92/"><img class="alignleft size-full wp-image-12495" title="1" src="http://www.tonepublications.com/media/1110.jpg" alt="" width="600" height="338" /></a>The First Watt J2 is an absolute honey of an amp. Hooked up to my Zu Essence speakers, the sound isn’t merely spectacular; it regularly keeps me up long after I should have gone to bed. The J2 is sublime, but I don’t think this point can be made often enough: when a reviewer says an amp is “great,” what he’s really saying is that it’s great with the speaker (or speakers) he’s auditioned it with. The same logic could be applied to speaker reviews because you can’t listen to speakers without listening through an amp. So it’s really the combination of the two – speaker and amp – that we hear. Sure, the rest of the system, namely the preamp, sources and cables, all play their parts. But the interactions between amp and speakers can make or break the sound – and with the high efficiency Zu’s it’s a winner.</strong></p>
<p>The First Watt J2 and Zu Essence are both made in the United States. Zu is a new wave, youthful audiophile company. First Watt is a Nelson Pass enterprise, and he’s the founder and CEO of Pass Laboratories. In the 1970s, his first venture, Threshold, broke new ground in solid-state designs, and he’s still advancing the state-of-the-art. First Watt exists because Pass wants to explore a variety of amplifier-design strategies in what he thinks of as “neglected areas:” amplifiers that might not fit into the mainstream and are probably not appropriate for Pass Labs.</p>
<p>The J2 is a stereo power amplifier rated at 25 watts per channel into 8 ohms, and 13 watts into 4 ohms. The clean, compact design measures 17 by 5.5 by 16 inches, and it weighs about 25 pounds. It has a two-stage circuit and operates in pure single-ended Class A mode, with signal JFET devices forming the input stage and power JFET devices for the output stage. What’s that, a JFET output stage? That’s special. Every solid-state amp you or I have ever heard used bipolar or MOSFET transistors in the output stage. The J2 sports JFETs, and that’s way cool.</p>
<p>Yes, I recall that Sony and Yamaha made JFET amps ages ago, but then power JFETs were MIA. Now they’re back. Pass heard that SemiSouth Corporation of Missouri had started making new power JFET transistors with high voltage, current and power capabilities – as high as 1,200 volts, 30 amps, and 273 watts. These new JFETs were designed for very fast switching in solar-power and electric-car applications. Pass bought a few of these JFETs and found they had a very low distortion characteristic. Compared with MOSFET-type power transistors, JFETs can achieve 10 to 20 dB improvements in distortion performance. So a JFET doesn’t need as much feedback to keep distortion low. It’s low from the get go.</p>
<p>Pass aims to design what he calls “simple circuits” because, as he once so eloquently put it, “Complexity tends to be the nemesis of musicality…” As he refines a design, he listens to how individual parts – capacitors, resistors, semiconductors, etc – change not only what he can measure but how they put their “signatures” on the sound.</p>
<p>Low-power, singled-ended tube amps have been popular with some audiophiles, especially those with highly efficient speakers, so you might assume Pass was trying to build a solid-state amp that would appeal to that crowd. But that’s not the J2
[Source: http://www.tonepublications.com/review/first-watt-j2-power-amplifier/]
<p>The First Watt J2 and Zu Essence are both made in the United States. Zu is a new wave, youthful audiophile company. First Watt is a Nelson Pass enterprise, and he’s the founder and CEO of Pass Laboratories. In the 1970s, his first venture, Threshold, broke new ground in solid-state designs, and he’s still advancing the state-of-the-art. First Watt exists because Pass wants to explore a variety of amplifier-design strategies in what he thinks of as “neglected areas:” amplifiers that might not fit into the mainstream and are probably not appropriate for Pass Labs.</p>
<p>The J2 is a stereo power amplifier rated at 25 watts per channel into 8 ohms, and 13 watts into 4 ohms. The clean, compact design measures 17 by 5.5 by 16 inches, and it weighs about 25 pounds. It has a two-stage circuit and operates in pure single-ended Class A mode, with signal JFET devices forming the input stage and power JFET devices for the output stage. What’s that, a JFET output stage? That’s special. Every solid-state amp you or I have ever heard used bipolar or MOSFET transistors in the output stage. The J2 sports JFETs, and that’s way cool.</p>
<p>Yes, I recall that Sony and Yamaha made JFET amps ages ago, but then power JFETs were MIA. Now they’re back. Pass heard that SemiSouth Corporation of Missouri had started making new power JFET transistors with high voltage, current and power capabilities – as high as 1,200 volts, 30 amps, and 273 watts. These new JFETs were designed for very fast switching in solar-power and electric-car applications. Pass bought a few of these JFETs and found they had a very low distortion characteristic. Compared with MOSFET-type power transistors, JFETs can achieve 10 to 20 dB improvements in distortion performance. So a JFET doesn’t need as much feedback to keep distortion low. It’s low from the get go.</p>
<p>Pass aims to design what he calls “simple circuits” because, as he once so eloquently put it, “Complexity tends to be the nemesis of musicality…” As he refines a design, he listens to how individual parts – capacitors, resistors, semiconductors, etc – change not only what he can measure but how they put their “signatures” on the sound.</p>
<p>Low-power, singled-ended tube amps have been popular with some audiophiles, especially those with highly efficient speakers, so you might assume Pass was trying to build a solid-state amp that would appeal to that crowd. But that’s not the J2
[Source: http://www.tonepublications.com/review/first-watt-j2-power-amplifier/]