Those Siemens are not bright at all. They have a very warm tone and they are also very detailed. Old recordings that sounded slightly harsh and brittle on other systems (like the Beatles white LP) sound fuller on the Leben. They temper the highs and make the sound more agreeable and less fatiguing. Very nice. Those Siemens quads weren't cheap and they'll only get more expensive so I should stock up on more of them while they are still available. I've also heard that some older Russian EL84s are good as well so I got a quad of those but haven't rolled them as yet.
Thanks, I shall take note of this.