This is the Shure 520SL desk top microphone, otherwise known as "The Dispatcher". It was a very popular microphone in the 50's through the 70's for general PA , amateur radio and dispatch use. It was also used by the military for PA and dispatch. The mic has the same element that was used in the Shure 520 which came with a high impedance CR or CM element. It was also available as a low impedance desk top microphone which had a model # of 520SLB. This desk top microphone was never available as a dual impedance microphone. The Dispatcher was made from 1950 through 1970, with the low impedance 520SLB becoming available in 1951.
This is a Shure model EM8A desk top microphone. It's a high impedance microphone like the 520SL with the only difference being the color. This particular mic has a model 99A86 controlled magnetic element with a date code of the second week of 1961. This is the only one I've ever seen and is part of my collection of mic's. I'm not sure if it was made to come as stock with a radio transmitter or something of that sort, but the model # is very similar to some hand held mic's made by Shure for General Electric. This sort of Navy blue is the original color of the mic.
The Different styles of 707A Microphones
Here are some examples of the different types of tag's used on the Shure 707A crystal bullet mic's from the early 1940's to 1970 when production of the 707A stopped. From left to right they are in order of the oldest to the latest. The first picture of the chrome mic is a tag from a 1943 model 707A that was originally a dark gray shell with a chrome grille, similar to the one next to it. The second picture is also an older model made in September of 1945. The shell has it's original paint which is a slightly lighter gray than the chrome model was. It has a rare light gray colored tag. I acquired it from a guy in Scotland and it's the only 707A that I have ever seen with the gray colored tag. Both of the 1940's models have raised lettering, serial #'s stamped into the tags on the right, and the model # on the left side. The serial # on the chrome 1943 mic is A3934, and the gray tagged mic has a serial # of 5547. The two 1940's models both are the smaller shell models. They are just slightly smaller than a full size 707A which is the same size as a 520 green bullet. To give you an example of the size difference, the smaller grille will fit onto a larger sized shell, but there will be a slight lip because of the larger diameter shell, and the larger grille's will also fit the smaller shells but the grille will have a slightly larger diameter than the shell. The total difference in diameter of the two sizes is about 3/32's of an inch. The early model 707A's used a crystal element with a model # 99-131 which was a Rochelle salt crystal element that was slightly smaller than the famous 99A94 and 99B94 crystal better known by it's replacement model # R7. The crystal element's can be seen on the element pictures page.
The third picture from the left is a 1950's model. I'm not exactly sure when the larger shells came into play but I think it's safe to say right around 1950. It was at this time that the crystal element's were changed to the larger sized R7 crystal which was used right up to 1970 when production of the 707A stopped. These tag's were black with raised lettering. Most of them looked like they were a dark brown color and no longer had a serial # on them. The chrome grille was no longer being used and the grille's were the same brushed nickel type as used on the 520 green bullets. The shells were now being painted light gray. These dark brown or black tag's were not used for too long because the light blue tag's as seen in the next picture were also used in the 1950's. They changed the design of the tag slightly and the lettering was still raised. The 707A was stamped in the box on the left side of the tag rather than in the middle as on the brown tag's. The light blue tag to the right of the black one was used through to the late 50's.
The last picture is of the last type of tag used on the 707A's. This particular mic is a 1964 model. The design remained the same as the previous tag, but the lettering was no longer raised and the blue background went to a darker blue color. This type of tag was used until 1970 when production of the 707A stopped.
This is the second green bullet I ever owned. The first was a Mexican made 520D. I acquired this mic at a hamfest in Rochester, NY for $20. It was owned and used by a local ham radio operator. It's basically a Shure 520 made for the Stromberg Carlson Co. of Rochester, NY. It is a 1954 vintage mic and has it's original black label 99B86 CR element in it. The model number on the tag is MR-34C. These mic's seem to be rather rare as I've never seen another, and only ran into one other guy who said that he also own's one.This mic is the one that turned me on to the true CR tone. Little did I know what I had at the time. I guess you could say that this is the mic that got me so interested in these things that I had to find out everything I possibly could about them, and is ultimately responsible for this website!
MORE PICTURES COMING SOON IF GODADDY CAN FIX THIS PAGE!