June 13, 2005

I have made my first steps into the world of tube audio equipment, and I find the whole thing a bit confusing, especially where new-old-stock tubes are concerned. Q: How do you know if a tube you are buying is new old stock, and how do you know if it's any good?

Peter Coleman

A: The realm of new-old-stock (NOS) tubes isconfusing, for the reasons you mention. First, whether a tube really is new old stock (and not old nearly used up stock) can't be determined in most cases. You simply have to rely on the fact that the tube tests within the limits of a new tube. The best sellers of NOS tubes test them prior to sale. As to the question of whether a particular tube is "any good," there you are on your own. Many tube audiophiles prize the sound of NOS Amperex and Telefunken tubes, and the prices of these tubes reflect this. I've had very good luck with other brands, some of which were made in the same plants as the Amperex and Telefunken tubes of yore. Experimentation is required to find tubes whose sound you like most. You can often buy tubes cheaply on eBay, some of which are tested before sale and some of which are not. You will generally pay more for tested tubes, and you can determine popularity based on the number of bids some tubes will garner, and what the selling prices are. You can find tube testers on eBay too.

...Marc Mickelson