The EV RE-20 and Shure SM7B are two great microphones. They are used by many broadcasters. Dynamic microphones like those don’t always have high outputs. That means you are going to have to find a way to amplify your recordings. These 4 in-line mic amplifiers can help:
Cloud Microphones Cloudlifter CL-1: this is quite popular among audio professionals It provides your microphone with a +25dB boost. It is compact and comes ready to go out of the box.
Sanken HAD-58 In-Line Amplifier: provides your microphone with 20db or 40dB in gain. The amplifier is built into a XLR-F/XLR-M adapter. You don’t need a battery to operate this.
Fethead Broadcast: a low noise amplifier with a rugged enclosure. It offers 23dB of amplification and has reverse polarity protection.
Cloud Microphones Cloudlifter CL-2: similar to the first one but can handle two microphones. It has lifetime warranty.
Which one should you choose? It really depends on your taste. We have had a lot of success with Cloudlifter and Fethead amplifiers. These are more than useful if you are experiencing low output when using your dynamic microphone.