while our tubes undergo a proprietary refurb process like no other... true nos matsu are revered audiophile crown jewels
literature tells us these had legendary mullard influence and warm tooling via 'transfer of technology' licensing agreements
national tubes feature uniform noise free characteristics, long service life, and superior sound reproduction
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full amplification test 110 % gm (65 % good) + useful life test pass! no meter movement at all
our unique gm output test applies 225 vdc simulating actual circuit operations w/ filtered dc
twice tested! supplier double checked via tv7 for unparalleled accuracy, also leak gas short checked
ships fast well packed worldwide, and free postage
~authentic vintage hifidelity audio curation by caliacoustics~