If you buy used tubes from an unknown source you may score a bargain or you
may get burned. Buying online from unknown sources has both good and bad
aspects. For certain tube types that are no longer manufactured you may have no
other options.
Again, be careful here. Most
people who sell used good tubes just plop them in a tube checker, and if the
checker says the tube is good, they sell it as a "good" used tube.
Best advice is find a reliable source and stay with 'em.
The only foolproof way
to determine if an audio tube will perform well is to use it in an actual live
circuit. Many tubes that check good on a tube
checker can sound bad in an actual live amp. A tube checker cannot tell you if the
tube is noisy. Also, a tube checker cannot predict how a particular tube is
going to sound your amp.
Go to the NOS (New Old
Stock) Tube Source Directory here.
