1) holographic warm sound reproduction (leading brands: mullard gt britain + telefunken/siemens germany) 
2) pleasant long-listen full frequency extension (leading brands: siemens germany + mullard gt britain) 
3) natural tone w/ flat response transparent mid-range (leading brands: telefunken + valvo + siemens germany)
4) precision bass w/ depth and rich resolve (leading brands: siemens/valvo germany + amperex heerlen)
5) musical linear sound reproduction (leading brands: amperex heerlen + siemens germany + mullard gt britain)
6) clarity w/ layered detail + smooth compression (leading brands: telefunken/lorenz germany + tungsram)
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the sonic top echelon from siemens germany! w/ original rca boxes these 1966 editions are one of the best tone years ever
siemens tubes are regarded as reference grade, musical warm involving and less sibilant than amperex bugle boys
this brings more extension depth especially important for instrument delineation, vocal fidelity, and lush cymbal splashes
the crimped getter neck delivers holographic linear transparency and bass kick, pure uncolored sound reproduction
ga2=6a / ga2=6k, the last of the warm tone years for siemens germany! later production were quite harsher + brighter
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often compared to telefunken, siemens tubes have less compression and more depth resolution, phenomenal mid-band imaging
top ranked must-listen lively upgrades for stereos, preamps, rode k2 ntk mics + hifidelity apps... upgrade your sound today!
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full gm conductance test 94/93~125/125 % mutual gm (65 % good) + useful life test pass! a key longetivity indicator
our unique mutual gm output test applies 225 vdc simulating actual circuit operations w/ filtered dc!
mutual gm scores = current transfer ability, especially important for push pull amps
also twice tested for unparalleled accurary! via legendary tv7/hickok 539c
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full sound auditioned w/ closed back high resolution monitors and aira preamps
we pride ourselves on a proprietary complimentary value-added complete refurb screen and deox process
give 100+ session hours w/ your specific amps voltage to fully cure (break-in is important)
ships well packed worldwide, includes original rca and freebie siemens boxes + free postage!
~authentic vintage hifidelity audio curation by caliacoustics~