[Silverface]

med - you could, but only if the plate voltage the measurements are made with are the same as the amp you're using.

One note - depending on the source, many online tube sellers (mostly of the eBay variety) match the tubes using some sort of Hickok (or other brand) tube tester. The plate voltage in these testers usually only tops out at 165-180 volts or so, making the "matching" with them pretty irrelevant for guitar amp applications.

That being said, I'm one of those that will match my own tubes with that type of tester and then check 'em with a bias probe in an amp...but I also agree with eman's statement about slight mismatches often being more toneful. Matching can be overhyped. Heck it *is* overhyped - as long as you don't have hum problems and the amp sounds good (and you're biased in a safe range) up to 10% can sound pretty darned cool in some cases.

Remember one other caveat - if your driver isn't balanced you might as well buy your tubes at the electronics swap meet. Hehe, but then sometimes I'll intentionally unbalance a driver....

It's a sickness.