I have the Littledot LD-Y2 300B headphone amp. And the pre-amp tubes are 6SH7, normally with metal shells. They are not expensive, about $5-$10 for a single and $10-$20 for a matched pair. Recently, I have dropped the metal shell tubes a few times to my desk while handling them. Though I can't...

There have been a few discussions of these tubes and related on here, so @UntilThen suggested I create this thread. I also know @Monsterzero and @whirlwind have some nice variations of these tubes. I have spent quite a few years learning and collecting these tubes, and I'd like to share that...