All tubes are tested on a Jackson Dynamic Tube Tester Model 115. Recently discovered New/Vintage old stock from one of Long Islands premier amplifier repair technicians. This was part of his own private stash used for vintage guitar amps and HiFi stereos. I recently bought the contents of a local repair shop.As such i will have a ton of vintage amps, guitars. The item "Quad Of Vintage Electro Harmonix 12AX7 Tubes NOS Matched Guitar Amplifier Amp" is in sale since Monday, June 14, 2021. This item is in the category "Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Parts & Accessories\Vintage Tubes & Tube Sockets". The seller is "wolfnsx" and is located in Hicksville, New York. This item can be shipped worldwide.