Further liquidation of my over-sized tube collection. Here's every type of 12AU7/A Tung Sol vacuum tube/valve ever issued From their first 12AU7, the one with the darkened envelope, to the last, a tube with an O-getter, gray plates and four crimps/staples per triode section, and everything in between.There're a lot of very nice 12AU7s here to try, and Tung Sols are a bit on the rare side compared with availability of other US tube manufacturers, like GE, RCA, and Sylvania. Here's a rough (based on visual features) evolution of the Tung Sol 12AU7/A: - Their first tube, circa late-1940s/early-1950s. Of particular note due to it's darkened envelope. Under that dark bottle were/are gray plates (though some very few may be black) and an angled, bent, raised getter ring and two plate crimps/staples per triode section. - Next up is a tube that looks like the above tube, minus the darkened envelope. Early-1950s. - Mid-1950s Tung Sol 12AU7s sporting D-Getter, but still with gray plates with two plate crimps/staples per triode section. - Mid-/late-1950s is a bit of mixed bag on construction details. Some D-getter tubes but now with four plate crimps/staples per triode section. The "A" type shows up around this time. - Late-1950s to early-/mid-1960s. This is the last of the Tung Sol 12AU7As. Gray plates, round getter ring, four plate crimps/staples. Here's what I've got: - 12AU7, D-getter, 2 plate crimps, 7 tubes available, $22.00 each
- 12AU7A, D-getter, 2 plate crimps, 10 tubes available, $18.00 each
- 12AU7A, D-getter, 4 plate crimps, 2 tubes available, $25.00 each
- 12AU7, O-getter, 2 plate crimps, JAN, 6418 date codes, 4 tubes available, $25.00 each
- 12AU7A, O-getter, 4 plate crimps, 3 tubes available, $22.00 each
See the pictures of each type in this ad. All are tested on one or more of my professionally serviced/calibrated testers (Dan Nelson and Roger Kennedy) - Hickok RD1575, Hickok 6000A, Heathkit TT-1, TV-7D/U. Some're used, some may be new (always hard to confirm NOS more than 40+ years on). Of course, test results and pictures will be provided for the actual tubes you're interested in. Contact me and we'll talk about what you're looking for. As always, negotiation is welcomed. Let's chat! Cheers. - SJ
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