While using a tube tester is the minimum testing that any tube dealer should do inhouse, we go a step further than other tube dealers. With our large inventory of guitar amps and audio gear we will often burn in and test the tubes in the exact device the tube set is being used in, that's real world testing. If you need pairs, quads, sextets or octets don't worry. All of our tubes for our tube sets are always matched at no additional cost to you. We've just added these amps to our existing testing inventory! Ampeg SVT Classic Fender Twin Reverb Blackface Fender Deluxe Reverb Mesa Boogie 3 Channel Dual Rectifier Marshall JCM-2000 DSL100 Vox AC30HW2 We are currently having a great sale on Genalex Gold Lion tubes. Please see http://analogtubes.com/tubeshop/index.php?main_page=specials for details.