Mesa/Boogie SPAX7 preamp tubes are a premium-grade 12AX7 that possess an even higher standard of overall performance due to their incredibly low sensitivity to microphonic noise. This is a go-to preamp tube to use in critical gain stage applications, particularly in first stage/input positions or other high-gain stages in the preamp tube string. These tubes go through a rigorous 12AX7 testing process and, when found to be substantially more stable and quiet in extreme high-gain applications, are then fitted with a shrink-wrap shielding, further stabilizing the tube and reducing external interference and noise. Mesa/Boogie SPAX7s deliver the lowest noise floor for the highest gain output, providing an excellent option for tubes to have on hand as spares and for any applications where the absolute lowest noise floor and low-microphonic response is needed.
 
UPC: 809404004603