History of the “Green Bullet” Microphone
The Green Bullet mic, also known as the model 520, was introduced in mid 1949 by Shure Brothers Inc. of Chicago, Illinois. It was intended for use as a high quality, moderately priced microphone to be used mainly as a communications, recording, and public address microphone. It became popular with ham radio operators as well as commercial use as a dispatch mic for police, fire, and other commercial dispatch uses, as well as military use. The mic was tailored for good speech response, and was made to withstand temperature extremes, and to be practically moisture proof. It is unaffected by weather extremes and salt spray making an ideal choice for coastal areas.
The mic was offered in 1950 with a stand and a handle with a built in “squeeze to talk” handle, which was known as the model 520SL. It was the exact same 520 mic with a built in desk stand and a squeeze to transmit switch. Shure also introduced a medium impedance mic, model 520SLB in 1961, which was meant for use where a long cable was needed between the transmitter and the microphone. The 520 mic without the stand was also available as a medium impedance mic called the 520B in 1952.
Element Impedance
Impedance is a measurement of a microphone’s resistance when certain voltages are applied to it and is measured at certain frequencies. It’s a rather complicated formula and is difficult for the average person to completely understand. In just about all instances when it comes to people asking someone with a mic for sale what the impedance of the microphone is in ohm’s, what they are really asking for is the DC resistance of the microphone’s coil, or in the case of the Shure 520 Green Bullet, the DC resistance of the built in transformer winding.
Impedance is often refered to as “Z”, such as High Z or Low Z. So just to make things clear, throughout this website, when I refer to “impedance”, I will be refering to the microphone’s element DC resistance as measured in ohm’s. For example, when I say an element has an impedance of 1,100 ohm’s, I am refering to the DC resistance with no load or voltage applied to it. This is not the real definition of impedance, but it is what just about everyone is asking about when they ask for an impedance reading of a mic or element.
The high impedance model’s had an impedance (DC resistance) of about 1200 to 1350 ohms in the first few years of production. The medium impedance models were 150 to 320 ohms, but later on in 1961 became available in a 15 ohm model in which the element model was labeled 99C86. The medium impedance models had an element model # 99E86. Over the first 10 years, the high impedance elements had model #’s that were 99A86, 99B86, 99G86, and 99H86, although the first green bullet mic’s were made using the model 99A86, and later on in the early 50’s changed to 99B86, and then 99G86 in the late 50’s.
Multiple Element Models, Same Build
These models were all basically built the same way, with the same materials, although they were used in many different types of mics including mics made for other companies such as RCA, Wilcox Gay, Bell & Howell, General Electric, Revere, and Telectro, to name some of the more popular companies of the day. Shure also made mics for many other lesser known companies, as well as the military.
The majority of the mics made for other companies were made for reel to reel tape recorders, console units that had recording capabilities, and mobile or base station radio applications. Not all of these mics incorporated high impedance CR or CM elements. In fact, many had crystal and ceramic elements. The mics carried many different model #’s, way too many to list. The Shure models that came with a desk stand and PTT switch were known as “The “Dispatcher” (models 520SL & 520SLB).
Green Bullet Shells
The green bullet mic shells were made of die cast zinc, and had a green painted body and a brushed, or “satin finish” nickel plated grille. The very first shells did not have an ID tag on them, but very few without a tag were produced. These were the very first 520’s made in mid 1949. The element was mounted in a rubber gasket that had a metal “shield” ring glued into it. The rubber gasket provided an airtight seal around the shell, and around the element itself. Being pressure actuated elements, this helped with the response of the element especially in the lower frequencies.
Shure also made a few different types of handheld mics using these same element’s, but used a different way of mounting it. They put a small plastic cup on the back of these elements and sealed them with tape to provide an airtight chamber on the back of the element to help increase low frequency response. Although some people do use them in the green bullet shells, they did not come that way from the factory and are not needed since the shell itself makes for the airtight chamber behind the element provided the mic has the proper gasket in it.
I’m not exactly sure when they were added, but I do know that the 1950 models did come with a 39K carbon composition resistor across the leads of the elements. The 1949 models did not, at least the very first ones didn’t. I was told by the guys at Shure that this resistor was put on to roll off some of the high frequencies. From what I’ve seen, most harp players like them better with the resistor removed.
Shell Tags
Sometime in, I believe, late 1949, Shure began to put a metal tag on the shell with 2 small pins to secure it to the shell. The very first tags had the lettering embossed in silver, and the background of the tag was painted the same shade of green that the shells were painted. I have only seen this type of tag on models that were dated 1950. I have only seen one 1949 model in green, and it had no tag, or holes to mount the tag.
The only other 1949 model I’ve seen is one that I own, which I believe is a rare introductory model made for Shure management or employees upon the introduction of the model 520, or something of that nature because I have never seen another like it. Its shell is all brushed nickel, and is the old 40’s style smaller version of the 707A style shell, which as far as I know, was never used to make any production models of the 520.
The smaller version shells were used only for older Shure crystal mics such as the early 707A’s, and 7A’s as well as the all brown bullet mics with the “Specially Designed for Recording” tags on them. The crystal mic shells had no small vent holes in them as do all the 520 mics.
The Controlled Reluctance Elements
From 1949 to sometime around June of 1958, the microphone elements were called “Controlled Reluctance Transducers“. They were described as being a magnetic unit, with its stability assured by unique control of the reluctance of the magnetic system, with good response, high output, and high impedance without the need for an external transformer (1949). Shure claimed to have a frequency response of 100 to 7,000 cycles per second, or Hz. The list price for a 520 in 1949 was $16.50. In 1959, the price went up to $22.50, and the 520SL had a list price of $45.00.
Over the first few years of production of the controlled reluctance transducers (which I will refer to as “CR‘s” from now on), Shure experimented with different materials, but only minor changes were made. The construction of the element remained the same, but they used different glues to secure the metal foil diaphram to the center pin of the magnetic armature assembly, and also experimented with different sized windings on the built in transformer.
In the very first few years of production of the CR element’s, Shure used a plain black piece of cloth tape with the model # and date code stamped on the tape with silver ink as the elements label. Sometime around early 1954, Shure started to use a white label with the patent #’s and other information on the labels with the model # and date code stamped in red ink on the label.
It appears that Shure started making the windings smaller over the first several years, thus reducing the impedance readings slightly. An improvement was also made to the magnet holder assembly making it much easier to assemble by switching from a 4 piece magnet holder, to a 2 piece magnet holder. I’ve seen 1949 elements with impedance readings close to 1,400 ohms, and it seemed that over the first 6 or 7 years, the readings consistently went down and settled at about 1100 to 1150 ohms in the late 50’s. Most of the white labeled CR’s will have an impedance reading in this range.
From 1960 on, the readings for the high impedance models dropped even further then remained pretty consistent at roughly 1050 ohms. Contrary to some peoples belief’s, the impedance reading (DC resistance!) has nothing to do with how “hot”, or how much gain the element has, at least not at differences this small as used on this type of magnetic element. There are many other factors that affect the gain and tone of these elements which I will explain in the Elements section of this website.
The CR elements first used in the 520’s had a black tape label over them with the elements model # and date code stamped in silver ink on them. There are a bunch of different model #’s on these elements which we’ll get into later, but the very first model # used in the 1949 model 520 had 99A86 stamped on it with an obvious date code that looked like this for example: “10-49”, stamped right beneath the 99A86. All of the 1950 models that I’ve seen are also very obviously dated in the same fashion. I believe it was in 1951 that Shure went to a date code system using a 3 digit date code beneath the model # on the element. In 1961, Shure went to a two letter date code system. (More on element dating later).
There seems to be some big hype about the black label CR’s these days that really, I think, is just that, hype. Granted, they do sound great, but so do the white label CR’s and CM’s (controlled magnetic transducers). I really wouldn’t go so far as to say that they are superior tonally than the white labeled CR’s, or even the CM’s.
Generally, CR’s tend to be slightly grittier sounding than CM’s, due I believe to the metal disc that is glued to the foil diaphram. Other than that, there is no difference in construction of the CR’s as compared to the CM’s. The black labeled CR’s are more resistant to the heat of a soldering iron since they have a phenolic bobbin for the built in winding (transformer) which also supports the main leads of the element which do get hot enough to melt the plastic bobbin’s used on the white labeled CR’s and CM’s. If this happens, the main leads can become loose or may melt right through the plastic bobbin and become detatched from the bobbin if you’re trying to pull a wire off the element lead that is wrapped around the loop at the end of it.
Many mics were made with the wires connected to the element wrapped around the loop. If you happen to have an element like this and you’re trying to remove those wires, it’s best to clip the wires as close as you can to the loop with wire clippers without cutting into the looped end of the main leads of the element. Then heat them again and remove the remaining wire as quickly as possible. It’s a good idea to have a small wet sponge available to quickly cool the element leads once the loop has been cleaned, or when attatching the leads to a mic shell.
The black CR’s are tonally about the same as the white ones. As I mention many times throughout this site, this type of element, because of the way they are constructed and the way they work, will sound different tonally from one to another even if they are of the same model # and even the same date code.
However, sometimes you’ll come across one or two elements that stand out from all the rest. This goes for all types of this element from the black CR’s to the Mexican made CM’s. When you happen to find a really good black CR element, they do have a fantastic tone and really strong output. They may be slightly stronger in gain and may have a very strong mid presence which is a bit stronger than a good strong white CR or CM, which I think is why some people rave about them. However, finding one like this is not so easy. A very small percentage of them stand out from the rest and they are not easy to find these days.
In my opinion, an average black labeled CR is about as good tonally as an average white labeled CR. Keep in mind that they all will differ in some way from one to another, so if you find one of a certain model that sounds outstanding, don’t expect all others with the same model # to sound just as good. Their model #’s really have nothing to do with how they sound as long as they are of the same impedance. There are many different factors that determine how these elements will perform which I do mention later on.
The black labeled CR’s were made from mid 1949, up until some time in late February, or early March of 1954, when Shure started using a white label with the Shure name, model # and patent #’s as well on them. The black labeled elements had a small white sticker on the side of the elements with that same info on them. These elements were all made with a transformer bobbin made of a phenolic material that could withstand a lot of heat. This was a great design that kept the main element leads in place because the phenolic bobbin also supported them.
At about the time the company changed to the white element labels, they also switched from using the phenolic bobbin to a plastic bobbin. The plastic material cannot handle much heat before it starts to melt, which did nothing to improve the quality of the elements, but were likely much cheaper to produce. There is really no other logical reason to switch to the plastic bobbins other than to cut the cost of production because the phenolic bobbins would not melt and cause the lead wires of the element to become loose, or possibly detached from the bobbin itself.
The elements were still being called controlled reluctance transducers when the label change was made in early 1954. Although almost all the white labeled CR’s you’ll see have a plastic bobbin, some white labeled CR’s with a phenolic bobbin were produced, although they are not common. White labeled CR’s with the phenolic bobbins were only made for a couple months.
The white labeled CR’s were used in the green bullet mics up until roughly March of 1958, usually with a model # of 99G86 before Shure started calling the elements “Controlled Magnetic Transducers”. The difference between the early black labeled elements and the white labeled elements is minimal as far as tone goes. There were physical differences such as the phenolic bobbins, and the magnet holder assembly which was refined over the years. Electronically, the early black labeled elements had slightly larger transformer windings, which is why the elements in the fist few years of production had slightly higher impedance readings. This didn’t make them tonally any better than the later white labeled elements or any higher in gain.
As I mention throughout the text on this site, all these elements will differ tonally from one to another based on many different factors. However, if you happen to come across a black labeled CR that really stands out from the masses of all the others, it’s likely to be one of the hottest, best sounding elements of this type that you’ll ever use, but coming across one like this is not a common occurrence. Why this is I really can’t say for sure. It may be something to do with the magnet assy, the armature gap or something of this nature. You could go through 100 of these elements before you find one that really stands out, so don’t set out to find one without expecting to spend a small fortune.
If you do happen to come across one of these elements, you’ll know it right away. If I could compare one to another element, I would say that a really good CR would sound similar to a new 707A crystal, better known as an R7, but the CR’s are grittier sounding and don’t have quite as good high end sparkle as the R7’s, and not quite as good bass response but the mid presence and overall tone, and gain are about the same.
So you don’t get confused with the statement under the black label picture, the 99A86 model # was used in the Green Bullet mics in 1949 only. The 520 was introduced in mid 1949, and the very first 520’s had this model in them. They did not have the resistor on them as seen in all the models built from 1950 up until they stopped producing Controlled Magnetic Transducers in 1996. Sometime in late 1949 or early 1950, Shure began putting a 39K resistor across the element leads to roll off some of the high end response. Most harp players like the tone better with the resistor removed.
At about that same time, the 520 element model was changed to 99B68. The model 99A86 elements were made well into the 1980’s and were used in many different types of microphones. The 99B86 elements were used in the Green Bullets up to the time that they changed to the white label in 1954. The element model was then changed to 99G86 and was used up until sometime in late 1958 or early 1959. Most of the white labeled CR elements used in the 520 were labeled 99G86.
When they started labeling them as Controlled Magnetic Transducers in 1960, the model number was changed back to 99B86. Physically, there is no difference between the 99B86 and 99G86 models. The 99A86 models are identical physically as well, but the negative lead on the element is not grounded to the body as it is on the 99B86 and 99G86 models. Why this was done I don’t know. They all sound about the same tonally, and there are no ground hum problems with any of the models that are not grounded.
Typical white labeled Controlled Reluctance Transducer
CR-CM, What’s the Difference?
In mid 1958, Shure changed the description of the elements and started calling them “Controlled Magnetic Transducers”, which I’ll refer to as CM’s. The model # was also changed to 99B86, from 99G86. The two models were identical in construction for the most part, but the metal disc in the middle of the diaphram was no longer being used. They were described as being, “pressure operated units using the balanced armature, controlled magnetic principle”. They were also described as having a high output level, smooth response, and a semi-directional pickup. Frequency response remained the same as the early CR’s at 100 to 7,000Hz.
The only physical difference between a CR and a CM is that the CR’s used a small, cymbal shaped metal disc to glue the foil diaphram to the center pin of the magnetic armature assembly, whereas the CM’s simply used a small blob of white glue that hardened like modern day epoxy. I would imagine that it was some type of epoxy glue that they used in place of the small disc being glued to the diaphram, that wasn’t available previously. The glue used on most of the early black labeled CR’s, these days tends to become brittle and will often come loose from the foil diaphram making the element sound weak. This is something that I see often and it can be repaired if done carefully without damaging the diaphram. The only other thing that I know of that is different from the CM’s is the location of the transformer wires where they come off the transformer and head over to the copper lead wires. I doubt this has any affect on the tonal qualities of the elements. The metal disc found on the CR’s on the other hand I would think would have some affect on the tone, being that it’s right on the center of the diaphram. What affect it has if any I really can’t say for sure, but it seems to be that the CR elements have a slightly raspier tone to them than the CM’s. The CM’s have a blob of glue in that exact spot and probably has the some affect as well, whatever it may, or, may not be. I can say this with confidence, I’ve had many CM’s that sounded as good as any CR, but a bit less raspy.
The tonal qualities of both CR’s and CM’s will vary from one to another in one way or another. Most of the time, the tonal difference will be very minor, but other times it can be drastic. It’s due to the nature of the beast. In other words, it’s due to the materials used, and the way they are made and work, (more on the way they’re made later) but they generally all have the same flavor if you will, just that some will sound a bit different than others, even those that have the same model # and date code. This is more often seen in the oldest elements these days because of age deterioration, and corrosion that can form under the magnet assembly which knocks the armature out of alignment. The magnets themselves can also loose strength if exposed to strong magnetic fields too, (from being stored inside amp’s with big ceramic magnets) or many drops to the floor, which will also make a magnet go weak and will affect the performance of the element.
THE LATER YEARS
The Different Shell Tag’s
In 1961, Shure had pretty much settled on the winding size, keeping the impedance at somewhere near 1050 ohms. Over the past 5 or 6 years, Shure changed the appearance of the tags that were used on the shells. After the first tags that were the same green color as the shells, they changed the tags to a deeper sort of “Hunter Green”. The lettering was still embossed on the tag. Shure made a move from Chicago to Evanston, ILL sometime in 1956. It was during this period in time that the deep green colored tags were used. You will find them with both Chicago, and Evanston,ILL on them, which can help clue you in onto when a mic was made. I suspect that Shure started using the deeper green embossed tags shortly after 1950. A large majority of the CR tags are the deep green color rather than the same shade of green that the mic shell was painted. When Shure made the change of names from CR to CM, the tags changed again as well. The tag no longer had embossed lettering. They were a deep, sort of emerald green color with the same information on them as the old tags, with the model # and impedance stamped in the blank boxes.
In 1970, Shure began production of the 520D, which is a dual impedance microphone. The very first 520D’s were made in Evanston, ILL. The green tags were still used for these mics but Shure now was putting a serial # in the box on the tag where the impedance used to be. When Shure move production of the 520D to Mexico, the appearance of the mic tags was changed to the silver tags with black lettering that are still being used on the newest version of the green bullet mic, the 520DX, which is still being used today
520D
Dual Impedance Model
In 1970, Shure designed a dual impedance controlled magnetic transducer, and began to use them in the green bullet mics which were now being called the 520D. The element was labeled as model 99S556. The first 520D’s were made in Evanston, and for the first time, the tags now incorporated a serial # where the impedance used to be stamped. The tags were still the dark emerald green, smooth surfaced, and basically the same as the previous tags, except for the serial #. The grille’s on the US made 520D’s have a brushed nickel finish just like the older 520’s, and the shell’s were exactly the same color as the 520’s as well. The Mexican made 520D’s were painted a slightly darker green and didn’t have a glossy finish like the US made models, and the grille’s were no longer brushed nickel, rather they were painted silver giving the 520D a whole new look. I don’t know exactly how long the 520D’s were made in the US, but judging from the very few that you see around these days I would think that not very many were made in Evanston before Shure decided to retool the factory and get rid of the 1940’s machinery still being used to make the elements, then contracted the work out to a Mexican plant. So my guess is that shortly after 1970 when the 520D was introduced, the dual impedance CM elements being used in the green bullet mics were now being assembled in Mexico with US made parts. If you have an American made 520D with a readable serial number on it, I would like to know what that number is and the date code on the element. Please send me an email along with a picture of it if you can. I can’t post information that I can’t confirm. I’d like to see how high the number’s will go.
I have seen quite a few elements with labels that said “Made in the USA”, with the “Made in the USA” blackened out with marker and a stamp on the side that says “Assembled in Mexico”. I guess they wanted to use up what labels they had left before changing them to a new, totally different looking label. The tag on the shell was also changed dramatically. They were no longer green at all. They changed it to a silver aluminum tag with black lettering, the same as the present day 520DX tags but of course without the X.
I have heard many people say that the CM elements made in Mexico are inferior to the US made counterparts, but I have played many of them and can tell you that this simply is not true. In fact, my first 520D had a Mexican made element and it is just as strong, and has just as good tone as the vintage elements I’m used to hearing. I’ve had many, and played quite a few of other peoples Mexican made CM’s and I can’t say that they’re inferior at all. To me, I would say that they may be a bit brighter sounding, but not so much that they sound like a whole different element. Take into consideration that they all will differ tonally in one way or another too, no matter where or when they were made. I have heard some fantastic sounding Mexican made CM’s that could pass for a good CR even to someone familiar with these elements. So do not judge your mics by where they were made. Use your ears, not your eyes!
I’m not sure if it was in 1980 or later that Shure stopped production of the 520D in the US. There is a Shure web page that indicated the 520D being made from 1985 to 1996, but I know that the first 520D’s were made in Evanston, ILL. I would have to believe that this would indicate the 520D production in Mexico, because the 520D’s made in the US were being made in 1980. The one that I have is dated August 1980 and was made in Evanston. Its serial # is 511. I do not know how many 520D’s were made in the US, but it appears that production of the 520D did stop for a period of time until production was resumed in 1985 in Mexico until 1996.
520DX
In 1996, Shure began production of the newest version of the green bullet which is now the model 520DX. This microphone, according to Shure, is based on the old 520 we all know and love. The mic now came with a built in volume control in the stand hole, and a whole new element. Unfortunately, the 520DX does not quite stand up to the older green bullets tone. The new mic is a whole different animal. The 520DX has a dynamic element made with a plastic diaphram with a large plastic housing mounted behind it, and a transformer mounted to it with high and low impedance hookup leads. It claims to have a frequency response of 100 to 5,000Hz. Its tone is much cleaner than the metal foil diaphramed CR and CM elements, and just doesn’t have the bite and grit of a vintage green bullet element.
I wouldn’t toss it in the trash though, it’s better than many of the so called harp mics out there today. It does have a tone that is usable for blues players who don’t want that much grit, or for certain styles of music other than blues. Many guys do like the mic and having the volume control, but as you probably already know, a volume pot can be put onto just about any type of harp mic. The pot that comes with the 520DX is not exactly what I would call a high quality pot. It’s very small, sealed, and does get dirty even though it is a sealed unit and can’t be properly cleaned. I’ve replaced quite a few of them because of scratchy noises heard when turning the control. .Other than this, I can’t say much about them because I don’t use one at all. I believe they are still being produced today. In case you’re wondering, they can easily be converted to accept a vintage CR or CM element to turn it into the real deal.
The Popular Shells & Crystals
There are very many different mic shells out there today that make for great harp mics. The most popular are the Shure green bullet, the Astatic JT30, and the Astatic model 30 better known as “The Biscuit”. These three mic shells will accept just about any element you want in them including the vintage Shure CM and CR’s. The Astatic mic’s were mostly crystal mic’s, but some used ceramic elements, of which both have more of what I consider to be a “tinny” tone to them, and lack bottom end. They have an extended high end which really doesn’t help much if you have no bottom end, and this will increase amplifier feedback at higher volumes.
There are however some very good sounding crystal mic’s out there that do have a big fat bottom end. Most are older crystal’s, MC151’s from the 70’s and 80’s, and the best crystal’s ever made in my opinion, the Shure 99A94,99B94, and 99A47 which are the later versions of the 99-131 crystals used in the 707A mics made from 1940 to 1970. These crystals are better known by their Shure replacement model #, R7. Unfortunately, these crystals were not made well enough to last, and finding one today that’s still delivering it’s full potential is near impossible. There are still some good MC151’s around that seemed to hold up over time better than the R7’s but as far as I’m concerned, the R7 was the best crystal ever made. It had a big fat bold tone with plenty of grit and punch, with excellent low end as well. They sounded very similar to a very strong, fat sounding CR element, with a more refined high end that is slightly crispier.
The drawback to crystal mics is that they are fragile, and cannot withstand moisture and temperature extremes. Leaving a crystal mic locked up in a car on a hot sunny day can kill it dead. Being fragile, I don’t think you’d want to leave one out in the cold either. A Shure 520 will be unaffected by any of this. You can pull one out of the freezer and start playing. Heat is no problem for them either, and they will survive numerous drops. Don’t expect this from a crystal mic. Don’t get me wrong, I’m not downing crystal mic’s. The good ones have great tone, you just need to be very careful with them. I own about 6 crystal mics in my collection that all sound very good. It is a good idea for any gigging harp player to have at least 2 different mics to work with, to get different tones, and to have a backup should one fail. A green bullet and a good crystal mic is a great combination.
As I said, there are thousands of good mics out there that will sound great for harp so look around. You can get a good idea of what’s out there by visiting the vintage mic and amp museum at the Harmonica Masterclass Company website. You’ll see my rare 1949 520 there too! Read more about crystal elements on the “ELEMENTS” page.
OTHER BULLET SHAPED MICS FROM SHURE
Early Shure Bullets
The very first bullet shaped mic from Shure was the model 705A, otherwise known as “The Rocket”, because of its streamlined shape and the fins at the rear of the shell. This was a crystal model, and was made in 1938 only. It had a swivel base attached to it like many of the later larger mics.
In 1939, Shure introduced the model 50, which was identical to the 705A but was a dynamic version of “The Rocket”. There were 3 versions of this mic, the 50A, which was a low impedance model (35 to 50 ohms), the model 50B, which was a medium impedance model (200 to 250 ohms), and the model 50C which was a high impedance model of the dynamic version of “The Rocket”. This dynamic version of the rocket was made only in 1939 and was an all brushed nickel plated shell like the 705A.
Some of the other bullet shaped mic’s that Shure made starting in 1939 were the Series 5 mic’s. These mic’s were made only in 1939, and all except the model 5G were made in all brushed chrome. The model 5 mics were all dynamic mics. The 5E being a low Z model (35 to 50 ohms), the 5F was a medium Z model (200 to 250 ohms), and the 5F being a high Z model. The 5G was also a high Z model, but it came in iridescent grey paint.
The model 7 mics were also made only in 1939. The model 7 mics were crystal mics also known as the “Streamliner”. The model 7A was an all satin chrome model. The model 7S came in iridescent grey paint. Both were high Z crystal microphones.
The model 500 microphones were made in 1940 only, except for the model 500C, which was the high Z model also made in 1941. The model 500 was a dynamic microphone, with the model 500A being a low Z model, the 500B a medium Z model, and the 500C which was the high Z model. All were available in iridescent grey only.
The model 52, also called the “Econodyne”, was also a high Z dynamic model which was made in 1947 only. It came with an all brushed chrome body and grille, and had a very high output.
The Shure model 707A was a high output crystal microphone made from 1940 to 1970. There were a few different versions of this mic. The earliest models having the slightly smaller shells. The later versions had the full sized shell. Most were available in either a light or dark grey color with a brushed satin chrome grille. Another of the smaller versioned shelled mics was the model 9822A, and the 9922B. Both of these models were all brown including the grille although some were available with a chrome grille. These were also crystal mics that had a tag on them that said “Shure Crystal Microphone, Specially Designed for Recording”. These mics along with the 707A’s and other early crystal mics had a very high output crystal element with a huge bottom end. Unfortunately, it’s very rare to find any of these in good working condition these days.
In 1940, Shure introduced the 708A, a crystal mic also known as the “Stratoliner”. This mic was not really bullet shaped. It looks more like a miniature “bomb” that you might have seen falling from a plane in WWII. It was made from 1940 to 1958. It came on a stand and really didn’t make for a very popular harp mic because of it’s size and shape.
Some of the other bullet shaped mics made by Shure are the model CR41, the CR20, and the 440, which I may have mentioned before. These were just variations of the 520 and all had the full sized shells. The CR41 came in a robin’s egg blue color with a brushed satin grille and were made in the late 50’s. The CR20’s that I have seen were mostly low Z mic’s although I believe there were high Z models. These mics had CR elements in them. The 440’s were made from 1960 to 1970, and like the 520 were available as a 440SL and 440SLB meaning that they came with a desk stand with the squeeze to talk handle for dispatch and PA use. The 440’s came with the same 99B86 controlled magnetic transducer that was used in the later 520’s. They were grey, with the brushed satin grille and had a single larger vent hole in the bottom as opposed to the two small vent holes as on the 520’s. Shure also produced various bullet shaped mic’s for other companies to use with home console units that had recording capabilities. Two that I know of were RCA and Bell & Howell. These were usually the older, smaller shelled crystal mics.
Shure also made a full sized high Z bullet mic identical to the 520 for the Stromberg Carlson Co. of Rochester, NY. It had a model number MR-34C on the tag which was silver with a black background. These were made in the early 50’s and had the black labeled CR elements in them. You can see some of these other mic’s made for other companies in the pictures section.
MICS FROM OTHER COMPANIES
Turner
Another company that has produced a few mics very popular with harp players is the Turner Co. Turner produced a few mic’s that had fantastic tone for harp, and produced one of the better crystals for harp mics as well. The most popular of the Turners are the CD and CX mic’s, which were dynamic (CD) and crystal (CX). The CD has a strong output and very good tone. They had a very good low end, strong mid’s and decent high end, although not as gritty as the Shures. The CX has a very strong output with a good bottom end as well as a responsive high end. The mics were available in an all brown, or brushed nickel finish. The all brown mics had different model #’s which were BD, and BX. The CX and CD had the brushed chrome finish. The CX and CD both had a frequency response of 50 to 7,000 Hz, whereas the BX and BD had a response of 50 to 5,500Hz. Why the difference in Frequency response, I don’t know. As far as I know they used the same dynamic elements and crystals. Both the CD and the BD were available in low and high impedance versions. They have a rounded grille (high dome), and a fin on the top of the shell that make them hard for some people with small hands to get a good seal on. The fin seemed to be the Turner signature, as many of the older Turner mics also had the fin as well. The CD and CX are also about the same diameter as a green bullet, so they would be best suited for players with hands large enough to handle one of the larger mics, given the high domed grille and the fin.
Electro-Voice
Another popular company who made a few mics popular with harp players is the Electro-Voice Co., better known as just EV. The most popular models for harp were the model 605, and 606, which were much smaller than most of the other more popular harp mics in the 50’s and 60’s. They are both dynamic microphones having a plastic diaphram and a built in transformer. They have high output, a good bottom and mid presence with less high end response and grit than the Shure and Astatic mics. I believe both were available in high and low impedance versions. The 605 seems to be the most sought after of the EV’s, likely because of its small, streamlined shape and high output. The 605 and 606 are similar looking except that the 606 has openings on the sides of the mic near the top, probably making it less directional than the 605 which has a small grille opening. These shells seem to be popular with players with small hands as they are much smaller than most of the more popular shells and very easy to hold. Many players will use these shells with their favorite element as they will accept just about any of the more popular elements with a little custom work.
EV also produced a couple other mics popular with some players but they were too large and hard to handle for most players. They had a large, cumbersome and heavy piece of metal attached to them that housed an on-off switch, and a stand mounting piece that turned a lot of players off. Some guy’s had the stand mounts cut off to be able to use them easier and bypassed the switch, but the EV’s other than the 605 never really made it big into the harp scene of today, although they were quite popular years ago as vocal mics. There were as I mentioned earlier, so many different companies who made mics that made for great harp mic’s. Unfortunately, it’s impossible for me to mention all of them out there, (mainly because I don’t know about many of them), but you can get an idea of how many different shapes and sizes they came in by visiting the harmonica masterclass website and checking out the vintage mic and amp museum.