Ribbon microphones produce low level electrical signals and need preamplifiers with enough gain to amplify that signal without degrading it.  The preamplifier you use needs to have enough gain to amplify the microphone to a suitable level to efficiently drive the recording equipment (equalizers, compressors, A/D converters, recorders, etc.). If the gain is too low, the signal will not be strong enough to operate the following stages at their optimum level. The resultant performance will be lackluster, devoid of punch and possibly noisy. Obviously, for recording loud sound sources like guitar amplifiers, horns or drums, more signal is produced by the microphone and less gain is required from the preamplifier. But if the source signals are soft, as is often the case with acoustic instruments or voices, much more gain is needed. For maximum versatility we recommend that a preamplifier have at least 60 dB (or more) of usable gain capability. For very quiet sound sources, 70+ dB of gain may be required.