1) true holographic sound reproduction (amperex usa/heerlen holland + telefunken/siemens germany + mullard/brimar britain)
2) full frequency pleasant extended warm dynamics (heerlen holland + siemens germany + mullard/brimar britain + tesla czech) 
3) natural organic tone w/ flat response, warm rich imaging (telefunken/siemens/valvo/lorenz germany + mullard mitcham britain)
4) precision bass w/ depth and lush musical resolve (heerlen holland + siemens/valvo germany + ei yugo + tungsram hungary)
5) dynamics, musical warm sound stage (amperex usa/heerlen holland + siemens/valvo germany + mullard blackburn britain)
6) clear layered detail, subtle tone compression (telefunken/lorenz germany + tungsram hungary + tesla czech + toshiba japan)

reference grade 1960/1961 philips amperex are musical holographic gems you can feel in your fingertips, the breath of life
these rare 7dj8 versions have a bit more linear presentation compared to 6dj8 variety, w/ even more upper-register nuances
not to be confused w/ later builds, these early editions feature the most precious metals, like a live concert in your living room
the low-bass is also better w/ additional kick and depth, often compared to 7308 sound stages full frequency detail reveal
these limited run large halos provide warm lush airy ambience, sought after highs w/ immersive involving vinyl-style intimacy
the textbook 'dutch house' cymbal-style sparkley resonant sonic resolve is revered by audiophiles for vocals + instruments
the euphoric sound stage is also incredibly expansive, offering up more head room extension ~ a popular tuning choice

for amps that are tough on 6922/e88cc tube lifetime, 7dj8/pcc88 are a very popular plugin long life sub
whether tube mics / preamps or hifi stereos, upgrade your resolution and fidelity w/ grail ranked listening
authentic⊿  delta heerlen holland etch codes, 1961 dj/⊿ 1e ~ 1960 dj/⊿ 0j + amperex boxes included
all tubes are twice tested! plus sound circuit studio audio noise-free auditioned, and include free postage!
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full conductance test balance 114/113 ~ 110/108/ % mutual gm (65%) + useful life test pass! (key longetivity indicator)
our unique gm output test applies real world circuit voltages and has an impeccable gas short and leakage test
finding an audio grade 6dj8 can be daunting! most sellers don't check for phono-level noise or mic certify them
we also pride ourselves on a proprietary value-added complimentary complete refurb screening deox process
full studio sound auditioned w/ ultra high-res closed-back monitors and premium aira preamps
give 100+ session hours w/ your specific amps voltage to fully settle in (break-in is important)
ships well packed worldwide w/ boxes and free postage
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vintage authentic hifidelity audiophile / preamp / tube mic curation by caliacoustics
see our official site! rarities, new arrivals and reserve/request options 
+ limited special editions + rare true-nos sealed box + pinched waist +high-resolution headphones