12au7 versus 12au7A

i was just wondering if these tubes are interchangible.if not then what is the difference? thanks.

route907-14-2002 9:37pm

herman Details Discussions Posts This discussion Message User 2,253 posts 07-14-2002 at 11:46pm Copy Comment URL Report Comment Edit Delete The letter indicates a "later and modified version which can be substituted for any previous version but not vice-versa" according to my GE tube manual. It also says the letter does not convey any information about the nature of the modification.
gs5556 Details Discussions Posts This discussion Message User 1,234 posts 07-15-2002 at 02:42am Copy Comment URL Report Comment Edit Delete Both tubes are electrically identical. The "A" is a slightly more rugged construction which results in lower output microphonics (and the "WA" is a military spec version which is made for high vibration environments). I cannot see why they would not be interchangeable.
route9 OP Details Discussions Posts This discussion Message User 55 posts 07-16-2002 at 01:39am Copy Comment URL Report Comment Edit Delete thanx gang for the info.