decibelle wrote:Well, yes, I would definitely consider it, but . . . I may be misinterpreting, but I thought increasing the volume this digital way was less likely to cause distortion?
It's not so much distortion, but raising the noise floor to within an audible range.
decibelle wrote:My system as it is now sounds very good. If I were to introduce a preamp between the turntable and the receiver, could that create problems as well as solve them?
No, it won't so long as you use something that is at least halfway decent, between the Phono Preamp and the Receiver. Fortunately these days, it is possible to do this without the need to spend a fortune.
decibelle wrote:Before making any decisions, is there an objective way I can test to see whether what I tried actually did raise the noise floor?
Yes you can.
I'm not familiar with your particular DAW Software but if it has a facility to observe the recorded waveform and also perhaps a graphic Spectrogram so that you can observe where in the audio spectrum, the noise resides, it can be quite illuminating.
The images below were created using screen dumps of a truncated section from an original low-level recording before any noise reduction was applied. The top image is the original as recorded. The bottom one is the same file but with Normalisation applied.
You can quite clearly see that both the musical passage and the noise floor have been raised and in this instance, the noise floor became quite audible at low listening levels.
Hope this helps a bit...