Probably been discussed many times, but I must not be searching properly. I recently began running a stereo rig using preamps & a power amp and am wondering if the power amp attenuators should always maxed or set as needed? Based on preference? I've been running the attenuators at ~ 12:00-2:00 and utilizing the preamp's level control as the volume control. Only been in pretty low volume rehearsal situations, but we go live & loud Saturday. If it matters, the preamps are a B7k for the treble and a DHA VT1-EQ-Bass-Drive for the bass to a Crest Pro 2.0. Both drive the amp decently (at least in my world of zero experience). The VT1 has a bit of a hiss. I'm assuming it's because of the tube. Suggestions?