An interesting auction of unusual early tubes took place on eBay on Tuesday evening. The seller apparently didn't check common references, and may have been pleasantly surprised by what he had. This picture is rearranged, annotated and re-scaled to fit here, with the full link to the originals given below:



The conical-anode tubes are discussed in Gerald Tyne's Saga of the Vacuum Tube on page 153. The other tube appears to be a VT-11, as it has a Shaw base with what looks like a red wax fill, whereas I believe, CG-890s have ceramic inserts. The conical-anode tubes have their bayonet indexing pins at 45 degrees from the usual location, likely to prevent installation in a standard (navy-type, ~ well, pre-UV) receiver socket. Given the index location, I'll speculate these tubes may have been intended for transmitter applications.

To see the bases up-close, please go to the eBay link below, as I couldn't fit that picture into the above montage. (Next time I'll use multiple pictures, sorry.)

Bidding was rather amazing, and someone sure wanted those pretty things, price be damned. I had to drop out early, knowing $423 + shipping, etc. will do my family a lot more good than those wonderful rarities could ever amuse me. However, those cone-hats are really neat to behold.

Please see:http://www.ebay.com/itm/3-vintage-unknown-brass-base-tipped-globe-tubes-detector-amplifier/391668191010?_trksid=p2047675.c100623.m-1&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D40778%26meid%3D8acc9ab8bf1a4305b1885ac9cf8f39f5%26pid%3D100623%26rk%3D2%26rkt%3D6%26sd%3D201774227067

Comments and corrections would be appreciated.

OTH

WOW! All three have mica inserts in the bases. I have never seen a receiving tube with those, although I have a few early GE transmitting tubes with mica inserts....

That said, while the middle tube has the form of the VT-11, it is not marked as such. These were usually marked on the glass press inside.

Jim Cross