Andre VE3SP / VA3AGV
The were not design to be recording units,but for amateur\non-critical\radio use. In that role, and coupled correctly, the D-104 is a great communications microphone. Clean, CRISP, highly intelligible audio that makes each syllable perfectly understandable.
Larry King audio... nope.....ESSB audio...nope, but if you want that, spend a ton of money or use AM or FM. SSB was designed ( and works well ) to be an efficient, narrow bandwidth mode. The audio part of it was deemed acceptable ...and still is.
They always had crisp, CLEAN, and understandable audio.
Used D-104's usually need to be re lubricated, and it does not hurt to re-solder all contacts. Adding a electret element to replace a working UNDAMAGED original element is pure folly, and there are those that have done it. Kind of like putting a Ferrari engine in a Corolla and then hoping somehow that it will be a Ferrari.
There is NOTHING wrong with the audio of a D-104 if one remembers what it was designed to do, AND if it is not over driven AND is electrically and mechanically working.
Most new hams, however, have no idea of the tonal design plan that was incorporated into this mic and think it should sound like a studio mike. Then again, even experienced hams still believe that somehow, someway, SSB can become and deliver AM or FM quality audio easily. Sorry folks but there is one word preventing that.......BANDWIDTH!!