Hands-On Review: Lewitt PURE TUBE Condenser Microphone

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Hands-On Review: Lewitt PURE TUBE Condenser Microphone

In this modern age of digital convenience and computer-controlled audio production, the vintage sound of analog vacuum tubes remains highly sought after by musicians, recording engineers, and producers around the world. While many companies today recognize this fact and produce a seemingly endless array of clones of classic tube microphones, Lewitt has taken the rare path of bucking this trend and delivering brand new tube mic designs.

Aiming to marry the warmth and smoothness of vintage tube tech with the clarity and precision of modern mics, the Lewitt PURE TUBE is designed to deliver the nearly magical, premium sound of a tube mic that would normally induce instant bankruptcy in a (somewhat) more affordable, modern-style package.  But how good does it really sound? Does it live up to the hype? In this article, we will attempt to answer that by subjecting the PURE TUBE to a variety of sound sources, revealing just how well this modern take on classic technology gets the job done.

Lewitt PURE TUBE
Lewitt PURE TUBE

The Specs

Before I get into my experience with the PURE TUBE, let’s take a look at some of the specs. The PURE TUBE sports a gold-sputtered 1" mylar condenser capsule in a fixed cardioid polar pattern. Some users may groan at only one pattern for the price point (the mic alone retails for about $1K), but the reality is that few multipattern tube condensers can be found for anywhere near this price, and the cardioid pattern certainly gets the job done, being the most-used pattern in many studio recording applications.

Lewitt claims that the PURE TUBE features a “puristic” signal path free of semiconductors and capacitors, relying entirely on its hand-selected 12AU7 vacuum tube (ECC82 for British readers). Some of us audio veterans might find this a bit confusing, since the capsule of a condenser is by its very nature a capacitor, but I digress. The reality is that it lacks any capacitors, diodes, op-amps, or transistors in the signal path that might alter the expected tube sound.

The most impressive specs for this microphone are its self-noise and maximum SPLs. These two specs are the most common shortcomings of tube mics, because most celebrated vintage designs suffer from high noise levels and a delicate sensitivity to loud SPLs, making them typically unsuitable for very loud sounds like amplified instruments or drums. This is, after all, the reason why manufacturers began switching to solid-state designs in the 1980s. With some modern wizardry, Lewitt has managed to pack in an exceptionally low noise level of 7 dBA and an impressively high 132 dB SPL limit, which really extends the versatility of this mic beyond the typical tube condenser.

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In terms of frequency response, Lewitt markets the PURE TUBE as specially optimized for vocals. Looking at the tech graph, you can see that the designers achieved this by tuning the capsule for a gentle bass roll-off, starting at around 63 Hz with some light peaking in the 4 kHz range, with stronger emphasis in the very high 12.2 kHz range. These are, more or less, the fundamental frequencies for the human voice at typical recording distances (around 10"), although at greater distances that avoid the proximity effect, the bass roll-off is much more pronounced, starting at about 200 Hz. This ensures that the mic will capture and enhance the warmth and high-end response of the human voice, while avoiding excessive bass on instruments like acoustic guitars or strings. Good stuff.

Unboxing

I must admit that when my manager dropped the demo model off at my desk, the size of the package was quite surprising. I got to try out the Studio Set variation, which includes a shockmount, magnetic pop filter, external power supply (more on that later), 7-pin XLR cable, and soft case, all housed inside an utterly tank-like hard case.

This case is no joke, contributing significantly to the weight of the whole package and neatly holding the mic with all its accessories. While it was no small feat carrying this over long distances to my studio in Queens, I have to say that it was quite a nice feature, almost a requirement in my opinion, given the beautiful, if vulnerable, glass window at the front of the mic which proudly displays the 12AU7 tube. There was not a minute that I felt the mic was in even the most remote danger of being damaged, thanks to the extremely well-built case that even includes an air vent and gasket. 

Though a bit tight, the Studio Set hardcase is sturdy and convenient.
Though a bit tight, the Studio Set hardcase is sturdy and convenient.

The microphone itself is quite hefty, featuring a large body composed of durable, die-cast zinc alloy. Once again, Lewitt is taking steps to make sure this mic can survive the test of time, which you want to see in a major financial investment such as a tube condenser.

The technology may be vintage, but the design is ultramodern, with a sleek, black paint job that one of my musician subjects humorously described as “Batmobile-like.” She’s not wrong! This is further supported by the unique shockmount and pop filter design that, unlike most shockmounts, does not wrap entirely around the mic, allowing you to view the glowing vacuum tube in its full glory during a recording, while the pop filter magnetically latches to the top of the shockmount bracket. This equipment was extremely fast and easy to set up, with the pop filter design, in particular, being very convenient to “pop” on, literally, in an instant.

Like most tube mics, the PURE TUBE uses an external power supply, rather than simple phantom power. Unlike most tube mics, the external power supply is quite compact and easy to move around your studio. With all the connectors (including power and both XLR connections) on the front face of the power supply, it’s easy to put the PSU up against a wall, on top of a desk, or anywhere else, simplifying cable management.

In the Studio

I tried to throw a decent range of sound sources at the PURE TUBE with the limited time (and musicians) I had available. This includes vocals (the ideal subject), acoustic guitar, and electric guitar cabinets (not the typical tube mic subject). On almost all of these, I was fairly impressed with the mic’s performance, finding that it most certainly delivered on at least two features Lewitt markets it for: very low noise and silky, smooth high end.

One area in which the microphone excelled particularly was in recording an acoustic singer-songwriter. For these sessions, I recorded into a Universal Audio Apollo Twin Duo MKII Thunderbolt™. Obviously, since the mic is tuned for the human voice, it did very well at capturing the warmth of her voice while maintaining a pleasant, air-like quality in the high frequencies. It produced professional-level results on the singer’s voice, as expected of a quality tube condenser.

However, with the rich depth it produced along with a focused low end and supremely clear detail, I found it interesting how the mic's tonal characteristics seemed more akin to a high-end FET mic, like the classic Neumann U67, than what I’m used to hearing on a tube mic. This is not necessarily a bad thing though; it merely highlights the fact that the PURE TUBE is more than just a vintage-style mic clawing at past glories―this is a truly modern microphone designed for the styles, sounds, and applications of today’s artists.

This focused low end also did well on acoustic guitar, bringing out a warm and punchy sound on the player’s smaller than average miniature guitar. I was very curious how this small-bodied guitar would come through, and I was very pleased with the results. The guitar recording sounded full, with oodles of dynamics. The musician I recorded was particularly enamored with the way the PURE TUBE seemed to capture all the fundamental details and tonal qualities she was looking for while leaving out a lot of the fretboard noise, creaks, and other unwanted noises inherent in an acoustic guitar that she felt often plagued her recordings through other condenser mics.

The PURE TUBE was smooth and impressively detailed on acoustic sound sources.
The PURE TUBE was smooth and impressively detailed on acoustic sound sources.

Even when used to capture voice and guitar simultaneously, all the expected detail and nuance came through with plenty of depth. Usually, it’s difficult to do things this way because of limitations in mic placement, forcing you to sacrifice some detail on either the guitar or voice. The simultaneous recording not only sounded great to my ears, but it also had a real “recorded in a studio” sound with sonics so full and smooth, it almost sounded like a finished production, despite being raw.

Finally, I moved on to electric guitar. This was captured a little differently, with the recording taking place in the home studio in my apartment and through my MOTU 838 interface. The space was not ideal for this mic, with too much room noise, like my computer fan, being picked up by the ultra-sensitive PURE TUBE capsule. But having gotten a feel for the sound with the acoustic session, I knew that this mic, while capable of high SPLs, would do much better on jazzier and more alternative electric guitar, rather than high-gain rocking.

Though not a typical target of tube microphones, the high max SPLs of the PURE TUBE worked favorably on my beloved Princeton Reverb.
Though not a typical target of tube microphones, the high max SPLs of the PURE TUBE worked favorably on my beloved Princeton Reverb.

I recorded a few takes using my Stratocaster through some drive pedals and into a vintage 1977 Fender Princeton Reverb, a classic recording amplifier. I dialed in some spring reverb and on one track some tube-driven vibrato and tried to keep the tone floating around the “at the edge of breakup” range.

In the end, I found the results surprisingly good, with tons of warmth retained from the tube amp and a nice, full sound that would truly shine with a little compression. The picked parts with the bridge pickups sounded particularly well rounded and benefited from the inherent warmth of the PURE TUBE, while the modern-style clarity captures the bite and details for a fantastic balance.

Conclusion

The Lewitt PURE TUBE really impressed me. I admit, when I first saw the design, with its glass-bound tube front and center, I thought it might just be a gimmick and would amount to a nice, if slightly overpriced conversation piece in a studio. I was wrong. The results were just too good to ignore, and while I don’t think its quite as warm as some other (more expensive) options, it strikes an ideal balance between tube warmth and rich detail that makes it an optimal choice for acoustic or electric guitar, especially in jazz, funk, soul, or RnB, piano, strings, and male or female vocals in any genre.

The PURE TUBE was smooth and impressively detailed on acoustic sound sources.

It’s also worth noting that my recording subject loved the look, from the sleek design to the prominent tube. While producers can sometimes have a cynical view of things from years of working with countless pieces of gear, each touted as the best, we can forget what it feels like to experience the wonder of coming into a studio. In her words: “It makes me feel like it’s doing something magical to my voice as I sing!”

For more information about this tube condenser microphone, including additional features, specs, and highlights, be sure to check out the detailed product page for the Lewitt PURE TUBE. Or drop us a line below, and we’ll do our best to reply to your comments and questions.

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