Reddit mentions of PreSonus Studio 6|8 USB 6x6 192 kHz, USB 2.0 Audio/MIDI Interface with 1 Year Free Extended Warranty and Microfiber

> Shure MVi

Seems close although a deal breaker for me is an interface that uses it's USB input as both communication and power. In the case of the Shure, it limits what amount of phantom power can be used when plugged into an iPhone.

I also looked at PreSonus AudioBox and AGAIN it seems to piggy back it's only USB interface as power without a discreet power source, also it's totally unclear if it works with iOS.

Same thing with the entry level focus rite scarlet... until you get to the Focusrite Scarlett 6i6 (at $250), which finally seems to have a discreet power source form it's USB input. However, no idea if the pre-amps are good enough to boost an SM57.

This Tascam interface seems to be a bit cheaper at $150, takes two inputs and has discreet power. https://www.amazon.com/Tascam-US-16X08-channel-Audio-Interface/dp/B00MIXF2RS/ref=pd_day0_267_4

This higher end Presonus https://www.amazon.com/PreSonus-Studio-USB-Interface-Extended/dp/B073PT77HC/ref=sr_1_8 (although at $299 is more than I'd like to spend), also has a built-in sound meter, which is really handy for setting levels when plugged into an iPhone recording video with literally no software aids to check your sound levels. SUPER HANDY.

Finally this ludicrously cheap monstrosity from Behringer for like $99 https://www.amazon.com/Behringer-UMC404HD-BEHRINGER-U-PHORIA/dp/B00QHURLHM/ref=sr_1_5 no visible sound level meter, no clue if the preamps are shit