pair of used old stock mullard 12at7 ecc81 preamp audio tubes, blackburn gt britain vintage production
these are lower gm yet still usable emission = lower gain / bass response ...lots of life left in the right circuit
rare 1955 special track-tip square getter milky ring top b5l code w/ mullard glass imprint in base
1967 halo o getter b7g5 code w/ mullard glass imprint in base
vintage production w/ the most precious warm metallurgy of the tube-era
direct british import carefully curated screened and twice tested!
full amplification test 66/64 ~ 70/55 % mutual gm (65 % good) + our useful life and leak short gas check
our unique mutual gm output test applies 225 vdc simulating actual circuits plus filtered dc
also supplier checked via tv7 for conductance, while your results will definitely vary...circuit test = best test
all tubes undergo an added-value proprietary complimentary refurb process, one of a kind seller qc!
nos w/ no mica flashing = give 100+ session hours at your specific amps voltage to fully cure
ships fast well packed worldwide, combined postage is available
~authentic vintage hifidelity audio curation by caliacoustics~