STC Coles 4119 - Very Rare High Quality Double Ribbon Mic - like Beyer M160 M500

I have not found a way yet of opening the mics and having a look at the ribbon, so I do not know whether they use a normally corrugated ribbon or a piston one like the Beyer M160 does. The specs are relatively similar, frequency response from 50hz to 15 khz (less than a M160 but if you look at the frequency response curve they look very similar) and similar sensitivity.

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