Old schOOl mIc qUEstIOn


Well-Known Member
Dec 28, 2001
Hey all,
I purchased a very old mic on ebay recently and was suprised to find the connection on it is something that I've never seen before. Instead of your standard XLR, it has a round, screw on connection with metal in the center and some sort of insulating material between the middle piece and the outside area. I'm guessing pos. and ground. It resembles that of an antenna connection. The mic is a dynamic mic, made by a company called "Calrad". (made in Japan) It says 50ohms on it and has an on/off switch on the top. That's all I can tell you. I could not find anything online about the mic or the company. Does anyone have any ideas?


Well-Known Member
Feb 23, 2001
:) Hi Michael! That type of connector is called an amphenol type 2 conductor. It has been used on coax cable on everything from CB radio mics, antennas, small house PA systems like early Bogan products used for industrial systems, also in early TV broadcast equipment for video coax, home type tape recorders. It predates other connectors like the BNC, and XLR for common use. It provided a secure connection because most of the early mics were high Z, although some had lower impedance's at about 1 to 2k, providing a little extra cable run. The transformer is actually inside the mic rather than at the head of the pre.

Very good cable was needed for any serious runs, and even then there was considerable roll off in the highs. Unless you plan on just collecting this mic, for runs longer than 10' to 15', you may want to modify the mic by by-passing the internal transformer, and fitting an XLR pigtail at the mic end, with pins 2 and 3 to + and - respectively on the diagram, and 1 to case ground. I remember our first bands could only afford a Bogan PA amp, and all our mics had those connectors, EV's, early Shures and many other brands. There was always some noise getting in on the stage from something.