SM7a/b humbucker coil

  • Thread starter Thread starter CoolCat
  • Start date Start date
more pictures of disassembly -

The stand nut screw was weird- a square screw, the new SM7b with standard Phillips much easier, but this is the old one a button head screw with 4pt "square" screw.
Pic 1-5
Backplate and EQ and capsule wiring
following pictures- noted inner body is painted and wiring colors.
 

Attachments

  • SM7 stand nut SQUARE screw.webp
    SM7 stand nut SQUARE screw.webp
    66.4 KB · Views: 20
  • SM7 stand square screw.webp
    SM7 stand square screw.webp
    58.6 KB · Views: 20
  • SM7 stand square1 screw.webp
    SM7 stand square1 screw.webp
    73.9 KB · Views: 21
  • SM7 sqaure with tool bit.webp
    SM7 sqaure with tool bit.webp
    38.4 KB · Views: 23
  • SM7 XLR side.webp
    SM7 XLR side.webp
    66.9 KB · Views: 21
  • SM7 backplate n.webp
    SM7 backplate n.webp
    44.2 KB · Views: 21
  • SM7 backplate O.webp
    SM7 backplate O.webp
    65.7 KB · Views: 23
  • SM7 backplate Eq p.webp
    SM7 backplate Eq p.webp
    85.4 KB · Views: 20
  • SM7 EQ wiring q.webp
    SM7 EQ wiring q.webp
    111.1 KB · Views: 21
  • SM7 back capsule wiring.webp
    SM7 back capsule wiring.webp
    117.3 KB · Views: 20
That's really good for identifying how it should look! thanks for this.
 
Its one early version at least to note a bit. Outside the no-humbucking coil and the humbucking coil there's not a lot of difference seen.

Looking at the newer SM7b's I have there are good improvements imo, over the original ones.
1.Putting the XLR in the front seems to be popular (which can be done with any model of these)
2.The mic stand is now a Phillips/cross screw instead of this old weird square screw.

Seems most everything is still to the same spec/design and interchangeable from old to current. Some decal/label changes, nothing important.
As with old vs new in sound? gets crazy....the capsules and magnets etc, and age seems to be the "sound" difference debated forevermore. For gear collectors the old ones will go up in value

Shure has a number for the tiny screws pn 30D443E but they don't seem to sell them. Not much info on them I could find. But then another Shure Product seemed to have used the screw p/n and there were details its M25, and that's a o.08 size! 80 thousandths of an inch, so many people seem to lose them. To be honest 2qty hold the back plate/EQ plate fine but 4qty is the full set. I found that interesting as I need to order some. $7 for 10 of them or something.
UPDATE: Seems the tiny tiny backplate screws are technically called "2-56 x 5/16" , ( .086 dia x .31x Long ), the ones I got were too short in length so don't buy the 1/8/.11.

I also found the XLR shield wire intentionally not connected, with the black and clear wire going to the mic PCB. Because the pin 1 is connected to the case of the SM7, shield wire. There is a fine wire jumper from Pin1 to case ground. Inside the mic there's no green wire from the XLR. Anyway the old one works and noise was identical to my new SM7b.

In the picture it shows only black and clear going into the mic body and the XLR shows the pin 1 green with heat shrink on it? wierd. It works fine!
 

Attachments

  • SM7 XLR wiring green.webp
    SM7 XLR wiring green.webp
    82.7 KB · Views: 16
  • SM7 XLR green wire .webp
    SM7 XLR green wire .webp
    105.7 KB · Views: 20
  • SM7 XLR wiring.webp
    SM7 XLR wiring.webp
    27.6 KB · Views: 19
Last edited:
Is the noise the same when near a powered up wall wart or fluorescent light?
 
Just having the mics setup sitting idle, I didn't see any difference.

Thats the thing, my setup/room doesn't have a hum buzz issue.
I can only assume the engineers of Shure got it right.
Some mention in the older days of tubes and amps and radio station setups/rooms the humbucker -coil was needed.

My original curiosity was if the humbucker-coil changed the sound but if the humbucker coil is only active in the presences of noise, seems its just docile when not needed.
In guitars humbuckers and single coils sound different, so I wondered?
I haven't done anything in depth of the sound thing. I am impressed the old mic works fine and isn't too beaten up. Interesting history of the SM7...SM57 on steroids the Shure article said.

I don't know anything about setups in the 1970's or 1960's that would not only drive the SM7 but also the humbucker-coil being added.
 
Back
Top