Whilst it may seem like a strange time to be jumping into the tube market, Apos has been working behind the scenes on a number of additional tubes including the new Ray 12AU7 tubes that were sent to me in advance of their release.
Scarcity and excess demand is never a good situation for consumers and the past few years have not been kind to audiophiles looking to purchase new tubes for amplifiers and pre-amplifiers.
The availability of more common tubes; especially the ones used in pre-amplifiers and DACs may not be a huge problem — but it has become much more difficult to source really good tubes and not go broke in the process.
Output tubes are available from a variety of vendors and it’s not an issue to source EL34s, EL84s, KT88s, 6550s, and KT120s, but the prices have become almost stupid depending on the brand and quality. A matched pair of Western Electric 300Bs cost more than some amplifiers.
There is also the issue of counterfeit tubes that have flooded the market which is never a good experience for anyone. Quality dealers also don’t love the concept of returns when it comes to tubes because even they don’t know what they’re getting back from the purchaser.
Matched Pairs…
The description gets tossed around a lot by vendors but is there really a standard for how closely matched, two tubes need to be in order to be sold as a “matched pair?”
Some sellers do little more than test leakage and transconductance, and if both tubes show roughly the same results they are a matched pair.
Other sellers use curve tracers like the Tektronix 576 to provide measurements as well as plotting the anode and screen currents at a range of biases. Even among those using the same testing procedures, there isn’t a consensus on how tightly matched two tubes (or more) need to be to be sold as a matched set.
As a buyer, you’re almost throwing your money at something blind unless the seller has a proven track record of offering reliable and legitimate tubes; especially when it comes to NOS tubes that are very scarce and expensive at this point.
Most hardcore tube enthusiasts have some form of tube tester, but often they do little more than leakage and transconductance testing themselves. When you take a look at the price of the testers and the learning curve involved — it probably doesn’t make sense for most audiophiles to invest that much money into something they may only use rather sparingly. Buyers want something reliable that will give them thousands of hours of playing time.
Ray of Light…
So how does Apos fit into all of this?
The company is cherry picking the best available tubes from specific factories and offering the top 4-5% of the output under the Apos Ray branding. Some might even recognize the OEM behind the 12AU7s under review but when they are put on a tester — the differences become rather apparent.
The pair that I received was as closely matched as any pair I have in my collection with transconductance within 50 μ-Mhos for all 4 triodes. Likewise, the plots from eTracer overlay each other nearly perfectly.
So far so good but I can tell that some will still say that this is nothing more than Apos rebranding the best tubes available and upcharging for all of them.
Apos, however, is offering a 90-day warranty on the tubes and a money-back return policy if you don’t like how they sound. Remind me again how many independent sellers or “highly rated” audiophile retailers offer those terms.
The packaging is another point of differentiation; each tube is packed in closed cell foam inside a book-fold box that keeps matched pairs together (another issue with old-style packaging).
The only wish I have is that they would have put the tube model on the end of the box as well as the lid; those of us with dozens or hundreds of tubes in storage hate having to go through them to find the specific one you need. A bizarre nitpick but that’s why we’re audiophiles.
The Tubes
The tubes have a halo getter, short gray plates, dual mica supports, and gold plated pins. On one side of the tube is the “Circle A” logo in gold, and the reverse features “RAY” over 12AU7 which is finished in gold lettering as well.
The 12AU7 can be used in a rather wide variety of products and that flexibility is another element of their appeal; we used the supplied pair in a phono pre-amplifier, stereo amplifier, and headphone amplifier.
Each scenario required something slightly different from the tubes and it also allowed us to judge how reliable they were.
The driver stage in both the headphone and stereo amplifier require the tube to function as the voltage (gain) amplification before the signal is fed to the power tubes for current amplification.
In the phono pre-amplifier, there is no second pair of tubes in the signal path so the 12AU7s need to be quieter and cleaner or they will negatively impact the overall sound quality.
Sound
The Apos Ray 12AU7 proved to be somewhere in the middle from a tonal perspective; not as warm as my Mullards, and not even remotely as clinical sounding as my Telefunken and Siemens 12AU7s.
The Ray 12AU7s presented music with rather good soundstage depth, a slightly forward sounding lower midrange with less coloration, and greater top end extension.
In many ways, it proved to be a good option that offers some of the warmth you might want from a tube but without a loss of detail or clarity. It is definitely not a lush sounding replacement. They were also not noisy at all and I found that they were a very solid addition to the phono pre-amplifier even when used with low output MCs.
Conclusion
The Apos Ray 12AU7s are not the least expensive options out there which is going to raise the ire of some. However, if you can find me a better option that delivers excellent sound quality, reliability, superior packaging, a 90-day warranty, and proper matching — I’m more than interested to compare them.
We’re anticipating 6922s, 6SN7s, 7199s and hopefully other options offered with the aforementioned attention to detail and quality.
If Apos can continue to deliver this kind of quality long-term, buying premium audio tubes might be a less risky venture going forward.
Where to buy: $179.99 at apos.audio
Related reading:
