Skylab
Reviewerus Prolificus
Those short-bottle, halo-getter, offset T-plates are generally indicative of much later than 1956, aren't they? I have some like that I'm pretty sure are from the late 60's or early 70's. They sound pretty good, yes, although I prefer the earlier Sylvanias that are tall-bottle, bottom getter, and have the regular t-plates (not offset).