My earliest encounter with vacuum tubes came at about age ten, when I suddenly had become completely mesmerized by music. My family had a vintage Philco console stereo that was in good working order and boasted surprisingly great sound, especially from its FM tuner. My growing fascination with the console aroused my curiosity regarding its inner workings, empowering me to ignore the prominent “Electrical Shock Hazard!” warning on the rear panel and have a look inside the cabinet. The internal amplifier was populated by an impressive array of vacuum tubes, and I’ll never forget the hypnotizing glow of those brilliant bottles. Fortunately, all I did was look, as the amp’s lethal voltage levels could easily have killed me! When one of the console’s channels unexpectedly died, it very likely only needed a new power tube, but the conventional logic of the day was to consign the Philco to the scrap heap. Its eventual replacement—a GE close-and-play record player—provided years of reliable service, but its sound quality was a pale shadow of the tubed goodness delivered by the Philco.

By the time I started building my own audio systems, tubes were no longer part of the mainstream. I never considered anything other than solid state amplification for decades, until about five years ago, when a new gig at Stereophile found me in dire need of a tube amp for an upcoming loudspeaker review. The speaker manufacturer, Volti Audio, preferred tube amplification, and strongly recommended PrimaLuna as a brand that paired well with its high-efficiency horn designs. I reached out to an old friend, Alan Jones of Atlanta’s HiFi Buys, who kindly connected me with his PrimaLuna distributor, Kevin Deal of Upscale Audio. Kevin quickly assessed my needs, then overnighted an EVO 300 tube integrated demo amp that already had about 100 hours of burn-in time. With the amp already fully run-in, I could immediately proceed with my review, and the EVO 300 has been in my system ever since. Following my relocation to Charleston, South Carolina, in 2022, I had the luxury of setting up an additional system that featured all-analogue source equipment, and the EVO 300 has become its centerpiece. I’ve been reviewing a steady stream of new and reissued LP releases since then, and the EVO 300 now sees almost daily use.

I’d been working with John Soriano at Apos Audio on several review projects last year, and was particularly interested in evaluating a matched pair of the new RAY Tubes SELECT 12AU7 that he carried. The plan was to place them in the EVO 300’s input sockets, where they’d have the greatest impact on the amp’s overall sound quality. That’s when the wheels just about came off in the all-analogue room. I ended up replacing the full quad of PrimaLuna-branded EL34 power tubes—you can read about that convoluted process HERE. In the aftermath, the EVO 300 was fitted with alternating matched quads of Gold Lion and Sovtek power tubes, in combination with matched pairs of NOS Brimar and the RAY SELECT input tubes. The changes resulted in my complete reevaluation of the EVO 300’s worth, and its newfound ability to portray music in ways that thrilled me like never before. I was now hearing a significantly more musical amplifier, and the differences wrought by the upgraded tube complement couldn’t have been more dramatic.

A Chance Encounter with the CEO of RAY Tubes

I spend a fair amount of time on social media, especially Instagram and Facebook, where my posts are typically evenly split between audio-related commentary and personal rants on hot-button issues. In early January, I began to notice a fairly steady stream of Instagram stories and posts from RAY Tubes. I followed the company’s account and frequently Liked its posts, along with leaving occasional comments, mainly to express my love for its small signal tubes and to offer my support. RAY Tubes is a fairly new company, and helping spread the word made perfect sense to me, especially after I’d discovered its SELECT 12AU7 tubes came within an eyelash of matching the sonic NOS goodness of the much more expensive British-made Brimars I’d been interchangeably using them with in the PrimaLuna EVO 300’s input sockets. I was finding it increasingly difficult to hear significant differences between them!

One evening in early January, I commented on a quite visually stimulating Instagram post that highlighted RAY’s new RESERVE range of power tubes. To my surprise, the OP (original poster)—who I assumed was the company’s social media administrator or some low-level functionary—messaged me and started a conversation that stretched across a week or so. He eventually identified himself to me as “Nelson,” and in my zeal to find out more about the new RESERVE tubes, I inadvertently determined from another post that “Nelson” was actually Nelson Wu, the CEO of RAY Tubes. Nelson also made the connection that I’d been the guy who had raved about the SELECT 12AU7s in a Positive Feedback review I’d written about them. Following a string of congenial calls and conversations, Nelson expressed serious interest in having me hear his new RESERVE tubes and arranged to send me a full complement for the PrimaLuna EVO 300.

RAY Tubes Arrive in the Low Country!

The PrimaLuna EVO 300 can support a broad range of power tubes—even monstrous designs like KT120’s and even KT150’s—but its stock configuration features a quad of EL34 power tubes and six 12AU7 tubes. Four of the 12AU7 tubes are drivers, with the remaining pair placed in the input sockets. It’s no surprise PrimaLuna chose the EL34; it’s a classic pentode power tube design that’s equally at home in triode and ultralinear amplifier configurations, and is generally considered to possess a longer lifespan than certain other output tube types. And they’re revered for possessing sonic attributes that have entranced audiophiles and musicians alike for generations, including: a level of inherent musicality that many competing tubes can’t seem to touch; an increased level of midrange sweetness that adds articulation and refinement, especially to vocals; a abundance of detail that isn’t overly-analytical; and a really good musical balance of firm and deep bass, along with liquid mids and highs that are not overly “soft.”

While I was initially intrigued by the RESERVE KT88’s I’d seen on Instagram, Nelson quickly questioned my attraction to the KT88s versus EL34 varieties. My response was that while I was generally completely happy with the performance of EL34s in the EVO 300, I’d been wondering whether using a higher-biased tube like the KT88 might give me a bit more of a dynamic presentation when needed. Nelson mentioned that an EL34 variety was also being made available in the RESERVE series, and that might be a good starting point, in addition to replacing all the small-signal tubes in the EVO 300 with SELECT 12AU7s. He was convinced I would hear things in the RESERVE EL34s that I wasn’t hearing from other manufacturers’ versions, and I couldn’t argue with that, especially based on my already good experiences with his small-signal tubes. The EL34s would be coming from the factory in China, and while Nelson was confident that I’d have them within a few weeks, they showed up in only ten days!

Nelson gave me a lot of background on RAY Tubes and their manufacture; they’re sourced from a factory in China, in a relatively rural setting just outside of a sprawling urban area. Even though vacuum tubes no longer drive the industrial and military complexes of the Western world, they’re still in fairly common use around much of the globe, and many of the tubes produced at the factory in China are intended for non-audio uses. Much of the factory’s output follows a quantity-over-quality formula, where most of the tubes will easily fall within the specifications to perform whatever job they’re intended for. That process completely changes for the production of RAY Tubes, where RAY engineers onsite continually check the production runs to guarantee the finished tubes meet their high standards. The tube tolerances fall into the three categories they offer: the CORE collection (small signal tubes); the premium SELECT collection (a mix of small signal and power tubes); and the ultra premium RESERVE collection (power tubes only at this point). Only tubes that meet RAY’s strict tolerances are chosen for use. Once the individual tubes have been sorted and matched, they’re screen-printed with the appropriate logo that corresponds with each tube’s tolerance specification. It’s a fairly involved process that guarantees that every matched set of RAY Tubes is exactly that: perfectly matched.

RAY Tubes arrive encased in a “beauty box” that’s unlike anything I’ve seen from any tube manufacturer at this price point. Most ship their tubes in fairly nondescript paperboard boxes, packed in shipping peanuts inside a cardboard box—but not RAY Tubes, whose tubes arrive encased in very cool, hinged-lidded, foam-lined boxes with magnetic catches. Compared to the competition in this price range, based on packaging alone, the RAY Tubes are obviously a cut above the rest, but not only that; the tubes are strikingly beautiful! Most Chinese or Russian tubes, by the likes of Psvane, Ruby, Svetlana, Sovtek, Mullard, Tung Sol, and even premium brand Genelex/Gold Lion, tend to have rather pedestrian appearances with haphazardly screen-printed labels. The RAY Tubes are more uniform in appearance and more elegantly realized. The SELECT and RESERVE tubes also feature gold-plated pins, which add not only to their aesthetic, but their impressive functionality. They simply exude perfection!

Premium SELECT tubes are manufactured and tested to meet a higher tolerance standard, and will provide superior and more nuanced sound than tubes from the CORE collection. Only the best tubes from any manufacturing batch will ever emerge from the factory, and the SELECT tubes are the cream of the crop of any given batch. SELECT tubes are not only tested for their superiority, but placed in amplifiers and listened to under real world conditions by audio engineers. RAY Tubes insists that for most listeners, tubes from the SELECT collection are the best they’ll ever need, and will allow your amplifier to perform at its highest level.

Opening the box containing the RESERVE EL34 tubes revealed another surprise: the shape of the RESERVE EL34 is unlike any other EL34 or variant I’ve come in contact with, and more closely resembles the shape of a KT88. I did an online search, and could only find one EL34 variant, the Shuguang S6CA7-T, that looked anything like the RESERVE EL34. The RESERVE tubes are also coated with a layer of monocrystalline carbon for improved electron flow, increased heat dissipation, and reduced noise. The additional dissipation of heat provided by the coating also helps to extend tube life, which is always a very welcome benefit. Ray Tubes’ level of quality control is so intense, the company offers a one-year replacement warranty on all tubes against manufacturing defects, which is pretty astonishing for a vacuum tube manufacturer. When I ordered the new set of Genelex/Gold Lion KT77s last year, prior to their arrival I stumbled across several online threads that maintained that new Gold Lion tubes would randomly fail within the first week of operation—and one of mine did! That makes RAY Tubes’ one-year warranty golden for tube users’ peace of mind.

Use and Listening Tests

I use two distinctly different audio systems for equipment and music evaluations—one with an all-digital source, the other an all-analogue one. So far, the RAY Tubes have only been used for evaluation in my analogue-based system. That system features a pair of standmount XSA Labs Vanguard compact monitor loudspeakers, an updated homage to classic British monitor loudspeakers like the LS3/5A, running in tandem with a pair of Vera-Fi Caldera 12 subwoofers that supplement the bass response of the monitors with a couple of extra octaves. Also in the system is PS Audio’s superb Stellar phono preamplifier powered by the PrimaLuna EVO 300 tube integrated amplifier that now exclusively uses SELECT and RESERVE tubes. These have helped elevate the analogue system’s performance to a remarkable new level of goodness. Both mono and stereo LPs spin in this system, with a ProJect Classic EVO turntable mounted with an Ortofon Quintet Bronze moving coil cartridge for stereo LPs, and a highly modified Rega Planar 2 ‘table fitted with an Ortofon 2M Mono cartridge for mono playback. This is unquestionably the finest analogue playback I’ve experienced in any system that’s ever occupied one of my rooms, and that’s due in no small measure to the upgraded performance of the EVO 300 with its new complement of RAY Tubes.

Attributing specific changes in a system’s sound quality based on tube upgrades can be a bit of a slippery slope; there are no measurements that you can point to that would indicate any kind of quantifiable or empirical improvements. But I’d had months and months of listening to the same basic setup with no real changes other than to the tubes. That included fairly frequent swaps between the pair of NOS Brimar 12AU7s and the SELECT tubes, which I’ve grown to believe are much closer in character than I might have previously attributed. I’m still resolute on this: after only a couple of months, the full complement of SELECT and RESERVE tubes has resulted in a clear overall difference in the sound of my all-analogue system. My impressions have been consistent in every listening session since their arrival: the RAY Tubes imbue everything that plays with a perfect balance of analogue delicacy and impressive dynamics, with every listening session providing an almost ethereal experience. They add a new level of magic to my music I never dreamed possible. And I’ve been listening to music of every genre, including not only LPs I’m intimately familiar with, but new records that have been arriving for review nearly daily. Everything sounds amazing over this system.

With the new full complement of RAY Tubes installed, a small oddity occurs the moment I flip the PrimaLuna’s power switch to on: there’s a pronounced whoosh followed by what sounds like an exhale, or ahhhhhhh. I attempted to make a voice recording of the phenomenon for Nelson and his team, but my android cell phone didn’t do a very good job of capturing the event. Regardless, the entire duration lasts about 5 seconds, then everything else is as normal, and when the amp reaches stasis and is ready for playback, the sound is always superb. It’s not at all troubling, just slightly curious, and I’ve never experienced anything like it with any other tube brand.

Final Thoughts

Prior to my analogue system meltdown last year, where the entire quad of stock PrimaLuna power tubes failed simultaneously, I’d never given much thought to upgrading the tubes in the EVO 300; I thought the stock tubes provided playback that was as good as it gets. That is, until I received a pair of the SELECT input tubes. Suffice to say that from the moment I used them with either the Gold Lion or the Sovtek power tubes in tandem with either the NOS Brimar or SELECT input tubes, the latter sounding surprisingly close to the nearly twice-as-expensive NOS Brimars, the transformation of my sound quality was immediate and obvious. I couldn’t believe my ears; with new power and input tubes, I was hearing greater dynamics and midrange liquidity, improved levels of detail, and an impressive step up in musicality. I was astounded by the differences, even more so when I paired the SELECTs with a new set of RESERVE output tubes. And while no one seems to talk about hearing worthy improvements from replacing the driver tubes, I can’t help but believe that replacing all six 12AU7s with identical SELECT tubes has contributed an extra measure of goodness to my system’s sound.

RAY Tubes are sold worldwide, and are distributed for purchase in the US by Apos Audio. Many thanks to RAY Tubes’ CEO Nelson Wu for his generosity of spirit, and for making this evaluation happen. RAY’s SELECT and RESERVE tubes aren’t inexpensive, but compared to the pricing of some of the more esoteric brands out there, they’re an absolute steal, especially considering how very much they’ve transformed my system and enhanced my listening pleasure. Very highly recommended!

Price: SELECT 12AU7: US$ 179.99/matched pair,  RESERVE EL34: US$ 399.99/matched pair

RAY Tubes
raytubes.com

Apos Audio
apos.audio

All images supplied by RAY Tubes and the author.