addo_00

It's probably easier to rekindle this thread than start another! I'm looking to do the same thing as OP - I'm hoping to use a headset with an electret mic with a beltpack that expects a dynamic mic, usually that would be a Tecpro beltpack. It's rare for the companies I work for to use posh comms unless there's an external sound company involved. I'm hoping to use a Riedel Run Headset. Before I found this thread, I had been looking around all over the place to find a circuit that I could buy/use just so that I could pop it in a box with the necessary I/O cable connections. I've seen various boards for sale on Ebay that look like they might fit the bill, but they all seem to list themselves as preamps so if I went down this route I'm guessing that I'd need to probably pad the output down 40db as it would otherwise be a too high a level for the beltpack? These boards also have an adjustable output - In my mind that sounds like a useful feature (forgetting about the level being too high) as then I could turn the mic down so as not to be too loud for the other comms users. I'm not sure if I can add links to the boards on Ebay so I won't, but I searched 'Electret bias voltage adjustable gain' and the ones I'm looking at were some of the red coloured boards. For the power source, I was planning on using a 9V battery but is there any reason to use a lower voltage? On the spec sheet the operating voltage is 3-10V but could I, for example, get away with using a couple of AA batteries instead? If the boards I've mentioned above aren't suitable is there other methods of getting the mic voltage biased and with an adjustable output - does anyone even think an adjustable output is necessary?!