Not all Shure SM57 are created EQUAL... or are they?

I try to find out how different Shure SM57s from different eras can be to each other and in general, how large the tolerances between SM57s are.
I take 13 Shure SM57s, starting with vintage made in the USA SM57 Unidyne IIIs, going over various different Mexican made models all the way to contemporary 57s that you can buy today.
Speacial thanks to ‪@lordgraga‬ for letting me borrow two of his mics for this. You're a stud, mate!

SUPPORT:
If you want to support me, you can use my Thomann affiliate link for anything you buy there. I get a small commission at no extra cost for you:
https://www.thomann.de/de/index.html?...
I’ve started a Patreon where you can download full IR packs for the speakers I demo:
  / tojb  

If you want to support me directly:
https://paypal.me/theotherjohnbrowne
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  / the.other.john.browne  


Time stamps:
00:14 Intro
01:31 What's the plan?
02:12 Meet the Mics
02:42 Four different ears of SM57s - What I've learned about 57s
08:38 Meet the Test Rig / Tools

10:02 Graphical Analysis
18:12 Audio AB test with and without normalization

21:36 Audio Samples
21:37 Mic A - Unidyne III USA 1
21:53 Mic B - Unidyne III USA 2
22:09 Mic C - Unidyne III USA 3 (Jacob)
22:25 Mic D - Old Mexican 1 (Jacob)
22:41 Mic E - Old Mexican 2
22:57 Mic F - Old Mexican 3 (Broken)
23:13 Mic G - Intermediate Mexican 1
23:29 Mic H - Intermediate Mexican 2
23:45 Mic I - Contemporary 1
24:01 Mic J - Contemporary 2
24:17 Mic K - Contemporary 3
24:33 Mic L - Contemporary 4
24:49 Mic M - Contemporary 5
25:04 Mic N - Hybrid (F handle, J capsule)

Signal chain:

DI Track recorded with a Charvel So Cal with SD Black Winters into an Audient ID24
Reamped with a Radial Reamp Box into the Lichtlaerm Audio Prometheus
Mesa 412 OS with 2003 Celestion Vintage 30s
All Shure SM57s
Audient ID24
Reaper or REW
Youtube
Your crappy phone speaker
your ears