It always sucks to have to give a client some bad news; but hopefully this can serve as a warning for folks to be careful about buying SM57's from unreliable sources to send them in for upgrading. These SM57's looked absolutely authentic through and through... packaging, metalwork, mechanicals, weight, feel, paint job, print literature, everything... until I extracted the 'transformers' only to find that they are fake empty bobbins not connected to anything, just designed to look authentic under the glue inside the mic body. and the wires ran straight through from the moving coil to the XLR. I believe these mics do work out of the box, but sound more bright and nasal than a real SM57. And they cannot be modified. They are built in such a way that the moving coil element cannot be loaded with a transformer... it has to run transformerless if you want to get anything out of it at all. If you want to be able to identify these without taking them apart, you can do so with a meter. A real SM57 will have an output XLR impedance (measuring pins 2 and 3 with an Ohm Meter) of about 30-50 ohms. These fakes will measure about 600 ohms, give or take, because you are measuring the impedance of the moving coil element directly.
Caveat Emptor.
If you see an SM57 being sold as 'new' for anything less than $99, and esp if its being sold on eBay or Reverb or anywhere out of Asia; I would say avoid that sale. Pick up a new one from Vintage King or Sweetwater, its frankly worth the peace of mind.
Chad
Hello here!
Just got one from Amazon... I did not recognize the sound of « my » SM57 because I had one before, but I had loaned it and it was never returned to me.
I just thought that Shure had drastically lowered its quality standard, and that this latest evolution of the SM57 was - at least on the aesthetics - very disappointing: Satin body (the old one was matte), gray-yellow and flat grille (neutral gray front and curved grille on the old one), different SM57 and DYNAMIC silkscreen font (thinner on the counterfeit). Looking at the two SHURE logos with a magnifying glass, we notice that on the original is clear, while the counterfeit is smeared, which cannot be seen…