EVH ECC83/12AX7 tubes pass rigorous testing for microphonics, hum, physical characteristics and function. An exceptional 9-pin triode preamp tube - specifically designed and tested for modern, high gain amplifiers and standard equipment on EVH 5150 III® amps. Outstanding and consistent performance for mixing and matching to get beefy, high-gain attitude and tone from your amp. This tube has a huge amount of gain, with terrific output that makes it a great choice for driving modern, complex high-gain circuits. It has a tight, strong and relatively bright tone that can really liven up a weak or tired old vintage amp or a new amp with stock tubes. FEATURES Pair of EVH ECC83/12AX7 preamp tubes 9-pin triode design Perfect for modern, high-gain amp circuits Bright tone to liven up a weak amp Used in the 5150 III® signature amplifiers