2x TESLA ECC803S (CV4004 7025) Long Plate lk Siemens E83CC, Prototype Se, 100%++

2x TESLA ECC803S (CV4004 7025 ~5751), ~1960 Prototype Series, 100%/Matched, 124+129.where a new/unused tube should have S/gm = ~1.60 mA/V, good value for transconductance starts at 1.2 mA/V. Selected from a larger lot of NOS tubes.

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