First of all there's something that at least I miss:
1. What kind of preamp?
2. Where's the initial lowest volume setting? 6:00? noon? 3:00?
Otherwise I wouldn't understand how far you're turning your volume knob. If you turn it on maximum or connect your fixed volume source directly to an amp you have you'll probably get EXTREAMLY LOUD even on quiet passages.
If you still get your signal low either preamp or amp is at fault.
1. What kind of preamp?
2. Where's the initial lowest volume setting? 6:00? noon? 3:00?
Otherwise I wouldn't understand how far you're turning your volume knob. If you turn it on maximum or connect your fixed volume source directly to an amp you have you'll probably get EXTREAMLY LOUD even on quiet passages.
If you still get your signal low either preamp or amp is at fault.