Originally Posted by Matt Finley
Others on the market are the CloudLifter, and the one I’ve used for several years, the dBooster from Royer.
Besides boosting, they correct the impedance mismatch that affects Shure and a few other dynamic mics. See below for a link to an excellent article on the subject.

All of the ones you mention are good. Unfortunately, I must caution against the Klark Teknik Mic Boosters. These are brought to you by the same company that owns Behringer. Although some products are now good, I can't say that about the mic boosters which are cheap, poorly made and often noisy. This is too bad since they are the least expensive ones out there.

Triton Audio also makes variations on the FETHead that don't exist anywhere else. Besides owning a quartet of the dynamic mic version, I own a couple for boosting headroom on some of my condenser mics, too.

My favorite is the variable impedance Cloudlifter CL-Z . I only own one and wish it wasn't so pricey. It is my go-to for any of my ribbon mics and I use the variableΩ knob to tune low end response.

It's easy to make the variable Ω box to use between your mic and any other booster. All you need is a small, metal box, a little wire, a pair of surface mount XLR jacks (one each M & F), a 1kΩ variable resistor and a knob. Here's an article on impedance and dynamic mics that explains what such a box does and how to make an in-line version with a fixed Ω.

A properly terminated SM57 can be a really flattering mic with a nice top and smooth bottom—unlike the normal response generated by plugging into a 1300Ω–2400Ω solid state PA system, mixer or interface. Those were designed for the 600Ω Bell telephone standard that tube preamps were normally built to before the 1970s—so was the Vocal Master PA if anyone remembers those.

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