If your interface doesn’t have enough clean gain for an SM7B, the recording is hissy. The fix is a $150 in-line booster called a Cloudlifter. Here’s how it works and what else exists.
A microphone preamp takes the very low-level signal coming out of a microphone and boosts it to a level your audio interface can record cleanly. Every audio interface has preamps built in. The question is whether they have enough clean gain for the mic you want to use.
Quiet mics like the Shure SM7B and the Electro-Voice RE20 need around 60–70dB of clean gain to sound right. Many sub-$200 interfaces top out at 50–56dB, which sounds hissy when you push them hard. The fix is an in-line preamp booster.
Beyond simple boosters, the world of standalone microphone preamps is enormous. Names like Universal Audio (Solo/610), Neve (1073, 1084), API (512c, 312), Avalon, and Grace Design represent a different category entirely — preamps that add their own sonic character to anything plugged through them. These start around $700 and go to $5,000+. They’re what professional studios use in front of even the best Neumann mics.