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Hi All, I found an old 1980 Bruel and Kjaer 4125 measurement mic that was given to me, while going through my old bits and pieces. I've never had this mic hooked up at all but it still has me intrigued. I would like to hear it at least once before it goes back into the box. I have the accompanying "type 2810 power supply" that appears to have a "battery" function. I cracked open the box but there is no battery slot that I can see. The mic itself is quite DPA-like, very miniature with a mini lemo connector. I don't see a battery compartment in the mic body either. Perhaps I could have the connector adapted for a more common power supply? The printed info label on the mic capsule storage vial says the following: Type 4125 Condenser Microphone Cartridge, Open circuit sensitivity at 1013 mbar, 23 degrees Celcius and 50% R.H. 140.8 dB re. 1 V per Pa. Capacitance : 14.5 pF (typically), Polarization voltage : 28 V, Frequency : 250 Hz, Date : 3-11-80 If anyone has any ideas about how to power this mic or has used one before, I'd love to hear your thoughts. Thanks kindly and have a great evening. Cheers, Dave