Time to liven things up in here!

My intuition is that a modest sized, untuned, unamplified loop, fed
with a matching transformer, should be quieter and yield a better S/N
ratio than an amplified loop--even when the amplifier is itself very
'clean'. However, my attempts to build an unamplifed loop that is
quieter than--or even as quiet as--my Wellbrook suggest otherwise. Why
is this? Why doesn't an unamplified loop beat an amplified loop every
time when it comes to S/N ratio, assuming of course that it's large
enough to gather a healthy amount of signal to begin with? I'm
especially puzzled by this in light of the fact that the Wellbrook
appears not to be shielded in any way (or at any rate, that's what I
gather from a previous thread on that topic).

Steve