(assuming there is no impedance matching issues)
when you hook up subs at line level from your tube pre amp
you will drag down the performance by loading your pre amp into a lower input Imp.
Speaker level as Bondmap suggested works best in my experience. like Rel and Vandersteen
The other advantage of the Vandersteen is their easily adjustable High Pass unloads the amp from the lowest frequencies which lowers the whole systems distortion dramatically improves transparency and clarity.
JohnnyR Vandersteen dealer
when you hook up subs at line level from your tube pre amp
you will drag down the performance by loading your pre amp into a lower input Imp.
Speaker level as Bondmap suggested works best in my experience. like Rel and Vandersteen
The other advantage of the Vandersteen is their easily adjustable High Pass unloads the amp from the lowest frequencies which lowers the whole systems distortion dramatically improves transparency and clarity.
JohnnyR Vandersteen dealer