John Eppstein wrote:
Ah, the sticky label, yes. As to the rest of it, it didn't used to be different at all -
No John. The actual cartridge itself is constructed differently, and has a different type of perforated metal than the 57 one - throughout ALL ERAS, and some other small details including the difference in voice coil.
Look, it's OK to be wrong sometimes.
You are correct, it's easy to be wrong sometimes. This time I am not. I started doing surgery on these mics in about 1967, when I was still in high school, and continued doing it professionally until the ea4rly '90s. For one thing, changes in design made a lot of the repair technoques I had developed to be obsolete, as the cartridges became more reliable when they changed the design of the lead-out wires and solder terminals. That was in the mid to late '80s.
I ask again, how many years have you spent doing actual cartridge surgery on these microphones?
As far as "the actual cartridge being constructed differently" NOW, I wouldn't know - I have not done that kind of work for 10 or 15 years now.
As to the actual cartridge being constructed differently, There's some room for miosunderstanding here.
The basic cartridge on the SM57/58 m,ics has undergone at least two distinct iterations. The original one had the hair thin leads from the voice coil extending from the glued-down edge of the mylar about an inch, give or take a smidge and then soldereed down to a small fiberglass board which had two eylet/lug connectors on it and a hole in the middle where it attached to a bolt extending from the back of the cartridge proper. From this board there were two thicker secondary leads that extended back thgrough two of three holes in a rubber insert attached to the outer shell of the cartridge. There was one nut on the inside of the rubber piece with a washer that positioned the rubber's distance from the inner cartridge. On the outside of the rubber (which formed the primary portion of the cartridge shock mounting, the other portion being the rubber ring isolating the fron surface of the outer shell from trhge cartridge proper) there was another little fiberglass board that had another pair of lug.eyelet connectors. The secondary lead out wires were soldered between the holes in the eyelets between the from and back boards. The yellow and green transformer leads soldered to the lug portion of the eyelet lugs, which extended over the edge of the boards (but were generally bent up at right angles.) The bolt extended through the center hole in this boards and was secured by another lock washer and nut, which also attached the cartridge grounding lug to the cartridge. This lug attached to the black ground wire. This cartridge design was common to the early ASM57/58 cartridges and the Unidyne III (545) and Unisphere I (565) cartridghes. When one of the early 57s or 545S developed ":rotating head disease" from people fidgiting and rotating the front cap of the mic and breaking the hair fine wires from the voice coil I would disassemble the cartridge, resolder the broken leads, and reassemble the cartridge. At that time the voice coil wires were DEFINITELY copper, because you can't reliably solder an aluminum wire that this with normal solder and non-temperature controlled soldering irons because it burns up before it bonds and the enamel insulation had to be (very carefully) removed from the end of thge wire bvefore soldering, which would have removed any copper plating.
This construction on the early SM57s was IDENTICAL to the construction of the 545s.
About 6 months after I demonstreated this repair process (which according to Shure wasn't possible).to a pair nof Shure factory reps who were visiting Don Wehr's Music City where I had my shop, Shure came out with a redesigned cartridge that had the VC wires soldered directly to two small pieces of PC board glued directly to the inner cartridge, which took the place of the old inner terminal boards and the secondary lead-outs. These bits of PC board extend through a couple of little square holes punched in the remaining (formerly rear) board without being attached to it in any way. The board remains as part of the shock mount apparatus and to provids a little support to the grounding lug. This alteration in design effectively eliminated problems with rotating head disease and consequently put an end to probably 75% of my Shure mic repair business. I do not know if this coincided with the change in voice coil material or not. It was in the mid 80s, right around the time they came out with the less expensive transformerless versions. As I recall it was slightly before, but I would not swear to it. As the new design rarely broke and was not repairable if it did I wasn't working on many actual cartridges, although I did disassemble a few totally dead ones (shifted magnets, etc), just to see what was going on with the newer ones. I did repair a couple that had had the front of the capsule whacked off by drummers, but that was just a matter of regluing the from plastic phase plug and foam assembly.
There were also some alterations to the phase plug assemblies and to the configuration of the foam (older ones had flat foam, newer ones had foam with a domed (kinda) middle and a sort of "roll" around it, but I don't remember exactly what of those details changed when, as it wasn't anything I ever needed to do significant repair to.
The significant changes to the cartridge design occurred to both the 57 and 58 at the same time, which tends to reinforce the belief that there are no significant differences between the the core 57 and 58 cartridges. (There was no real reason to alter the 58 cartridge design, as the front of the cartridge was protected by the ball and not vulnerable to rotating head disease, but it changed at the same time.
The front piece of the cartridge assembly was, of course different between the 57-58/545-565 capsules. Originally this part was the same between a 57 and a 545, but this has been subject to at least one or two changes in the 57, mostly (I believe) to make it cheaper to manufacture, as the newer versions have fewer parts. I'm pretty certain that there were similar changes in the 58 cartridges, but, as I said I worked on far fewer 58s than 57s.
However the core inner cartridge was identical on botgh the older version 57s and 58s and on the newer 57s and 58s. Any sonic differences are caused by the windscreens, unless they acoustically test the bare cartridges off the assembly line and select for the different models, which I seriously doubt given the wide variance between individual examples of each model as revealed by the independant testing that Bill Graham's FM Productions has done during my tenure as bench tech there.
I am (as I've said previous) rather curious as to which, if any, of these design alterations have (or have not) been applied to the new production of the 545 (and 565, for that matter.)