BUYING "NEW OLD STOCK" TUBES, aka NOS VINTAGE TUBES

Here's a guide that helps buyers with the task of selecting and purchasing vintage vacuum tubes for high-end and vintage equipment, such as electric guitar amplifiers and audiophile power amps. The goal here is to help okayers better understand those cryptic data values and descriptions posted by sellers.When manufacturers such as RCA, GE, Telefunken, AEG, and Phillips, batch tested new vacuum tubes 40 or 50 years ago, they published a nominal or average value for a category of tubes which described that tube's electrical performance and characteristics. This published value, listed in tube service manuals, is called a bogey value.Makers of tube testers used this information to build and setup their equipment to reliably and accurately test tubes in accordance with the bogey value. The bogey was usually reported in micromhos (gm), the most gemon electrical circuit value used by manufacturers to report a general measurement of a tube's properties. So the question is: What does bogey value have to do with buying "new old stock," or NOS vintage vacuum tubes?Today, most buyers are looking for tubes described as "new old stock," or NOS; in other words, tubes that are old in age, but otherwise new. Thus, the acronym NOS is better understood. The gemon myth is that vintage vacuum tubes, stored away for decades in a mythical storehouse of neglected vintage equipment, are suddenly found by treasure hunters. In this mythical place of unused vintage tube stuff are found cartons and boxes filled with tubes which are new, never been used, never turned on, never lit up in a piece of equipment and are virgin, years later. Right!To be fair, every once in awhile true NOS vacuum tubes are in fact discovered and offered for sale, usually at high market prices determined by supply and demand principles.So what's the point? Most sellers, who call the vacuum tubes they sell "new old stock" tubes, are hoping that you will buy into that myth and buy their tubes just because they call them NOS! But how can anyone really claim to know the history of any tube that's 40 or 50 years old? Is it deceptive, possibly irresponsible, to use the term NOS to sell vintage tubes without test data to gepare with published bogey values?The Tube Tone Zone (TTTZ) also uses the terminology new old stock, and the NOS acronym. When TTTZ tests vacuum tubes and reports a measurement that is equal to or higher than its published bogey value, it may use NOS, or "new old stock," in the item listing description or headline. The key distinction, from a technical, internal circuitry standpoint, is that tubes found to be within a range of NEW characteristics, backed-up by tube tester data, are therefore considered NOS, "new old stock," at TTTZ, despite cosmetic appearances, labels, date codes and whether or not any history is known. These tubes can truly be called NOS because they meet or beat the published bogey value, the only valid and meaningful indicator available.RELIABLE TUBE TESTER DATA REVEALS A TUBE'S STATUS TODAY = FOR DIRECT gePARISON WITH VINTAGE BOGEY VALUES PUBLISHED YESTERDAYThis information helps buyers to make an informed buying decision. This information provides a definitive basis for evaluating the present condition of tubes they need.This information helps buyers to consider whether the selling price is affordable and within reason. What really matters in the life of a tube is whether or not it retains its electrical integrity when tested on certain recognized, laboratory grade vacuum tube analyzers that perform a full range of tests under the same or identical conditions used by the original manufacturers who published the bogey values in the first place. In the best possible scenario, by carefully reading a seller's listing description, a buyer should be assured that the required tube is within a range of newness, despite its old age, and that it will be suitable for use in expensive high-end and vintage equipment.Think bogey like in golf, as a way to remember this invaluable guideline next time you need to purchase vintage vacuum tubes for your precious gear.