The legendary SM57 microphone from Shure is turning 55 years old, which is a grand age for a piece of tech item still in production. It is allegedly the most used microphone of all time and if you ever held a microphone in your hands you have a good chance that it was (or some sort of derivative of) the venerable SM57.
Currently, it costs roughly in the region of about 100 GBP/USD/EUR new and in exchange you get a microphone which is basically indestructible. You can give it to Iggy Pop and unless he figures out to do something very extreme with it, you can be aSHUREd (apologies for that) that the microphone will still work after the gig. It is great for instrument recording and a fun fact that it was (is) the preferred microphone of all the US Presidents since 1965, except of course the POTUS whom wanted one, which picks up more of his wimpy low voice volume levels.

It is basically a simple dynamic microphone in a very sturdy metal case. It features a small dynamic diaphragm and a tiny transformer for a bit of amplification, so your preamps do not need to be cranked up too much. Actually, I believe there is a popular DIY mod what a lot of users seemingly suggests is to remove the transformer altogether and the mic will still be good, with improved frequency response. Modded SM57 owners are claiming that by removing the transformer makes the mic softer, quieter sounding and picks up more of the low-end frequencies etc. It just that it needs a little bit more amplification.
If you are a frequent bargain hunter on Chinese sites, such as Ali Express, you might have noticed the various clones of popular microphones, usually for about less than half of the money, what an original would cost you.

Some time ago I have bought two SM57 clones and I have to say I was quite impressed of the quality of the goods which I have received. Everything looked like the original, all the documentation, stickers, cases, everything. I still could not understand how it is less than half the price even after paying duties, etc. It works great, no complaint about it whatsoever.
So a few days ago I was researching microphone transformers for a project where I try to recreate a simple loose contact carbon microphone with a home-made transformer coil. I have bought a replacement SM57 transformer for experimentation and out of interest I wanted to see how it was wired in the microphone itself, so I have started to take one of the mics apart. After disassembly, I have discovered a little trick about these SM57s. When you unscrew the case and look towards where the transformer should be, there is a big blob of hot glue and somewhere underneath – you would expect – where the transformer can be located. It is almost visible under the glue.

I was thinking first, that this is a bit inconvenient if you would need to make repairs, etc. So then I have started to pry the glue out, when I have discovered that this SM57 has no transformer in it at all. The capsule is wired directly to the XLR socket and under the glue there is a fake transformer, basically just the plastic bit of the part, but without the windings and the iron core.

So there you have it. The answer how they can keep it cheap despite, I am Shure sure, that everything else is in fact the same as the original. I cannot really understand the effort to put a fake part in, but hey-ho. You can buy a ready modded SM57 from Ali for half of the money. (please call the rhyme police)
