Just started listening to my new-to-me Vali 2 (thanks @RickB ) I'm using the stock tube right now just to get a flavor for it. Plopped my HE4XX on my noggin and my first though was, "wow, that's definitely warmer." I've been listening to it for around an hour and I have already gotten used to it so I can't really tell anymore. Or the tube has warmed up. Either way, I'm a happy listener right now and exicted to try the other tubes I got with it (again, thanks @RickB ).