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I ordered a set of omni mics from sound pros that came with a preamp, but someone said that I needed to amplify the resulting wav file a lot to have it listenable.
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(Ive been using a damn dictaphone with a minicassette since 97...lol)
Should produce a much better recording than a dictaphone + mini-cassette! Only one way to find out if you'll need to add gobs of gain in post: give it a try.
The problem with adding lots of gain in post: noise. The lower your recording levels, the lower your signal:noise ratio (SNR). With a low SNR, when you add gain in post you're amplifying the signal (music) AND the noise by the same relative level. With higher recording levels you achieve a higher SNR. Since you have higher signal levels, you amplify less in post production, which means you're amplifying the noise (and the signal) less. To illustrate, and since I never pass up an opportunity to do a little ASCII diagram. Full scale represents your desired signal levels.
Recording with low levels, low SNR
Raw Recording Amplified in post
_____________ Full Scale _____________
------------- Amplified Signal
~~~~~~~~~~~~~ Amplified Noise
------------- Raw Signal
~~~~~~~~~~~~~ Raw Noise
With very low recording levels and a low SNR, amplifying the signal by a LOT - to get your signals up to Full Scale - also amplifies the noise by a LOT. And since you're applying the same amount of amplification to both the signal and the noise, and the ratio stays the same, you now have a strong signal, but also plenty of noise. B-a-d.
Recording with high levels, high SNR
Raw Recording Amplified in post
_____________ Full Scale _____________
------------- Amplified Signal
------------- Raw Signal
~~~~~~~~~~~~~ Amplified Noise
~~~~~~~~~~~~~ Raw Noise
With higher levels and a high SNR, the noise is relatively quieter to the signal. So if you do need to amplify after-the-fact, [1] you can amplify less, and [2] since the SNR is higher, even with added amplification the noise will still remain significantly lower relative to the signal.
If memory serves, you're recording unamplified voice/piano or some such, right? If you have the option, use the high-gain setting on your SP preamp, run line-in to the JB3, and see what happens.