j k, could you describe the differences in the LS-25 you experienced with these NOS tubes? I would like to try these with my LS-25 as well. I saw that Kevin has several models available on his site. Do you know which would offer a more harmonically rich sound with less treble detail than the factory tubes provided, as my Von Schweikert VR-6's are a bit much in the treble. Thanks very much for your suggestions. Also would you suggest replacing the output tubes to the same in my VT-100 Mk II? Thanks again.