Amperex 12AU7A Tubes Long Plate Foil D-getter - Rogers Label - Holland 1958

Perfect matched pair of vintage Amperex 12AU7A Long Plates Foil D-getter tubes - Made in Holland - 1958 - Same date code -  Very Rare Product Summary The "textbook Heerlen sound" has been referenced in several Soundlumia listings of Amperex Holland 12AU7/ECC82 tubes, and many tube enthusiasts asked what that all means. So this is the answer: the late 1950s and very early 1960s tone, the beginning of over a decade's excellence in sound, the classic tonal template for all the great (and greater) Amperex/Philips/Valvo/Miniwatt tubes to be made in the years to come, the timeless Philips radio tone that many of us grew up listening to.  Sound Qualities The most distinctive sound feature of the Heerlen 12AU7's is the transparent, natural and expansive midrange presentation, with a slight touch of warmth that illuminates your music. Every piece of music you play through these tubes sounds like from a vinyl record, whether your sound source is phono or not. The sound stage is spa