Help Identifying 12AX7 tubes

Tubes Asylum

Questions about tubes and gear that glows. FAQ

These are 12AX7GAP/R tubes removed from a Philbrick analog computer in the 70's. My father was working at AC Spark Plug and the analog computer was being decommissioned. He brought home a K2-W module including tubes and a couple of spare tubes for sentimental reasons.

Philbrick bought tubes from several manufacturers and had them relabeled as "GAP/R Computor" with a Philbrick part number. I'm not very good at identifying tubes, so I could use your help in understanding what they are and if they are interesting for audio. I have two which were used in the K2-W and two NOS spares. The GAP/R label says "Made in USA", but I would not bet my fortune on that.

Probably a dead giveaway is the gold paint octangle around the 12AX7 label. I've read about a "stop sign" label, but the rest of the description didn't fit these tubes, at least as I understand it.

The thing that is unusual is the getter. It is at an angle rather than sitting perpendicular to the plates. The getter is made from a wire bent in a 'C' with a stamped piece of metal closing the rectangle. The sheet metal has a couple of dimples in it.

Otherwise, it is a long plate (17 mm), ribbed plate 12AX7. On the bottom, in the center of the pins there is a letter in the glass. Mine have A, B, E, and R. There is also a faint number in the glass between pins 1 and 9. It is sometimes unreadable. I think I can see a 3 and a 5.

Any thoughts?

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Topic - Help Identifying 12AX7 tubes - lehmanhill 09:21:52 09/22/20 (7)

RE: Help Identifying 12AX7 tubes - Jim McShane 17:11:01 09/22/20 (6)

RE: Help Identifying 12AX7 tubes - Tom Bavis 07:34:46 09/23/20 (5)

RE: Help Identifying 12AX7 tubes - lehmanhill 08:55:37 09/23/20 (4)

RE: Help Identifying 12AX7 tubes - Jim McShane 11:50:38 09/23/20 (3)

RE: Help Identifying 12AX7 tubes - lehmanhill 15:12:11 09/23/20 (2)

Nice tube! - samstone 07:25:58 09/24/20 (1)

RE: Nice tube! - lehmanhill 11:44:59 09/24/20 (0)

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