2 Matched NOS Matsu/Mullard 12AT7 ECC81 Vintage Hifidelity Preamp Audio Tubes

2 matched old stock matsu japan hard vacuum 12at7 ecc81 preamp audio tubes. Legendary tone regard w/ mullard'transfer of technology, unique angle halo getters similar to rare valvos. Vintage'60s production w/ the most precious metallurgy of the tube-era = more accurate sound reproduction + warmth.

Direct japan import carefully curated screened and auditioned + twice tested! Full amplification balance test 101/100 103/101 % mutual gm (65 % good). + our life leak short gas check.

Our unique mutual gm output test applies 225 vdc simulating actual circuits plus filtered dc. Also supplier tested via tv7 for conductance, while your results will vary... Circuit test = best test. Nos w/ no mica flashing = give 100+ session hours at your specific amps voltage to fully cure. Authentic vintage hifidelity audio curation by caliacoustics.