I bought a pair of these on a whim from Ebay a few years ago. No date code, triple mica Raytheons. Really fell in love with the tube's sound. Using them on the input stage of my Manley Shrimp, in lieu of the 12AT7's. I have quite a few NOS brands, Mullard, Brimar, Bugle Boy, Sylvania. I also own most of the new production offerings, even the Psavanne's sold thru Grant Fidelity.
Anyhow, I think the 6414 bests them all at a very reasonable price from Ebay. I have since picked up 2 additional pair of Raytheons as well as 2 pair of GE's.
Thought I would share since they fall in between the price of new production and the low end cost side of boutique NOS.
Also have read that they can be subbed as a 12AU7, but have not tried them in this application.
I can verify that they work and work well in the 12AT7 slot.
