Short Answer: NOS tubes means “new old stock” — made years ago, but never used. And yes, some NOS tubes sound better than many of the tubes being made today. However, there are many things you need to know before you just start buying NOS tubes. For example, many NOS tubes aren’t really “new” — they are actually used. But unless they have been used to the point of failure, they can still in some cases sound better than tubes that are made today.
Full Answer: It’s a bit hard to say with certainty whether one class of tube is better than another. It’s like telling somebody which red wine is the best — everybody has their own unique taste, so a definitive answer is hard to state. Let’s start with current-production tubes. Are any of them worth investigating?
The Best-Sounding “New” Tubes — 12au7
To see which new-production tubes we like, check out our article on this topic here. As a quick summary, we like the Gold Lion gold pins (which also say ‘Genelex’ on them), the Mullard re-issues, and the Psvane “ART” series tubes.
If you have other new production tubes that you like in the 12au7 format, let us know by email at:
NOS Tubes: Better? Are There Disadvantages?
There are also many NOS tubes (and used tubes) that can be purchased, which were made anywhere from the 1940s to the present. Many tubes were made even earlier, but popular preamp tubes such as the 12ax7, 12at7 and 12au7 were developed in the late 1940s. These tubes were made under countless brands, in factories all over the world, including in the U.S., Holland, England, Germany, France, Yugoslavia and Japan.
Advantages
Not every NOS tube will sound better than the best of the current-production tubes mentioned above. But some do. In what way? Well, NOS tubes can provide more of a layered soundstage. A bit more three-dimensional. And a little more natural, almost “touchable” sound quality. For example, hearing Louis Armstrong’s gravelly voice…. With a new production tube, it might sound like a stunningly good recording. With a NOS tube, it might sound like Louis is even more “there” in the room with you. NOS tubes can also provide an amazing sense of space in, and around, the performers on a recording.
Disadvantages
However, there are several disadvantages or at least red flags that can pop up as you try to “beat” the sound quality of newly-produced tubes:
- NOS tubes are sometimes just flat-out noisy (hiss, intermittent static, microphonics, pops, humming, etc.)
- tubes sold as “NOS” are sometimes used, and can even be near the end of their lives
- NOS tubes are often very expensive, with some 12au7 tubes commanding over $1,000 a pair
- when you buy a pair of NOS tubes, although they will hopefully match in terms of the brand of tube, you will sometimes receive tubes that are different from each other, either in construction or date of manufacture
Despite these difficulties, in many cases (but not all) NOS tubes really can sound better than current-production tubes.
In the next article, we will discuss some of the best-sounding NOS tubes that come in the 12au7 format.
