First a simple truth - as long as your preamp is of professional quality and working properly, there is nothing about it that will prevent you making a good recording.
Preamps don't matter anywhere near as much as the currently popular myth suggests. Your musicians are important, their instruments are important, the acoustics of the room are important, your microphone positioning and microphone selection are important, your skills and artistry are important. The microphone preamp comes after all of that in order of importance.
But still, you might have concerns about your preamp, and one common concern is noise.
The correct way to set preamp gain is to increase it to whatever value that is necessary to achieve a good strong reading on the meters of your recording system, without clipping of course.
But you may find that when you do this, there is a lot of background noise.
This may be the acoustic background noise that is present in the room. Raising the gain of the preamp does raise this, but only in proportion to the signal you want to record. So the signal-to-noise ratio from this source of noise stays constant.
But it might also be that the noise generated by the preamp itself increases. This should not happen. In fact, many preamp manufacturers quote their noise levels measured at maximum gain, because this is where the signal-to-noise ratio is greatest.
So here is a simple test...
Now, there are three possibilities...
Of course, we have only discussed noise at high gain settings. But at least in this significant parameter it is possible to see clearly whether your preamp is up to the job.Come on the FREE COURSE TOUR