[Ron C[_2_]]

Story and minor rant:

I was asked to do sound for karaoke at a local VFW.
I pulled out some old SM-48s .. figured they'd be
adequate for that job.

When I checked them out they were all dead, no
sound what so ever.

[OK, I got the job done with other mic's ]

Anyway, later I pulled the top off the the 48's
and found the foam had turned to sticky goo.
Cleaned out the goo as best I could .. but still
dead.

So... I figured I could just replace the capsules.
Looked up the price and found they'd cost more
than new SM-48's!

Duh, this just doesn't seem right!

Anyway, I have a few nice SM-48 bodies,
hate to just throw them out .. any suggestions?

~~
OK, just lightly venting. End of minor rant.

--
==
Later...
Ron Capik
--

[Klay Anderson[_3_]]

Send them back to Shure. Theyll give you new ones for the price of repair or better.

[PStamler]

On Friday, November 30, 2018 at 7:15:44 PM UTC-6, Ron C wrote:

Anyway, later I pulled the top off the the 48's
and found the foam had turned to sticky goo.
Cleaned out the goo as best I could .. but still
dead.

So... I figured I could just replace the capsules.
Looked up the price and found they'd cost more
than new SM-48's!

Welcome to the economics of the modern microphone business.

Have you checked whether there's a break in the inteqrnal wiring?

Peace,
Paul

[Ron C[_2_]]

On 12/1/2018 6:35 PM, PStamler wrote:
On Friday, November 30, 2018 at 7:15:44 PM UTC-6, Ron C wrote:

Anyway, later I pulled the top off the the 48's
and found the foam had turned to sticky goo.
Cleaned out the goo as best I could .. but still
dead.

So... I figured I could just replace the capsules.
Looked up the price and found they'd cost more
than new SM-48's!

Welcome to the economics of the modern microphone business.

Have you checked whether there's a break in the inteqrnal wiring?

Peace,
Paul

Yes, I've checked .. no problems there.
Heck, the mic's are 20++ years old, so I guess
I've gotten my money's worth out of them.

I understand that electrets can become depolorized
but never thought dynamics would/could go bad just
sitting in a box. Live and learn.
--
==
Later...
Ron Capik
--

[Phil Allison[_4_]]

Ron C wrote:



Have you checked whether there's a break in the inteqrnal wiring?

Peace,
Paul


Yes, I've checked .. no problems there.


** Hang on - you say the internal wiring is all OK ( not corroded) and the mics are both dead ? Have you checked the voice coil with a DMM ?? A reading at the XLR of about 250 ohms shows it is intact.


Heck, the mic's are 20++ years old,


** Still within the useful lifespan for Shure vocal mics that get low usage.


so I guess
I've gotten my money's worth out of them.


** I disagree and think the foam wind sock disintegration is a separate issue to the mics going silent.


I understand that electrets can become depolorized
but never thought dynamics would/could go bad just
sitting in a box. Live and learn.


** Fine copper wire, as normally used for voice coils on mic diaphragms, corrodes under damp conditions and develops opens.

However, Shure mics like the SM57 & SM58 use much thicker wire for the voice coils followed by a step up transformer which goes a long way to extending these mics lives.



.... Phil

[Ron C[_2_]]

On 12/2/2018 6:55 AM, Phil Allison wrote:
Ron C wrote:



Have you checked whether there's a break in the inteqrnal wiring?

Peace,
Paul


Yes, I've checked .. no problems there.


** Hang on - you say the internal wiring is all OK ( not corroded) and the mics are both dead ? Have you checked the voice coil with a DMM ?? A reading at the XLR of about 250 ohms shows it is intact.


Heck, the mic's are 20++ years old,


** Still within the useful lifespan for Shure vocal mics that get low usage.


so I guess
I've gotten my money's worth out of them.


** I disagree and think the foam wind sock disintegration is a separate issue to the mics going silent.


I understand that electrets can become depolorized
but never thought dynamics would/could go bad just
sitting in a box. Live and learn.


** Fine copper wire, as normally used for voice coils on mic diaphragms, corrodes under damp conditions and develops opens.

However, Shure mics like the SM57 & SM58 use much thicker wire for the voice coils followed by a step up transformer which goes a long way to extending these mics lives.



... Phil


Damn, I hadn't thought to check for an open voice coil.
Yep, they both measure as open. Corrosion of the super
fine wire is quite the logical explanation.

Thanks.
--
==
Later...
Ron Capik
--
..

[Phil Allison[_4_]]

Ron C wrote:

Phil Allison wrote:


Have you checked whether there's a break in the inteqrnal wiring?

Peace,
Paul


Yes, I've checked .. no problems there.


** Hang on - you say the internal wiring is all OK ( not corroded) and the mics are both dead ? Have you checked the voice coil with a DMM ?? A reading at the XLR of about 250 ohms shows it is intact.


Heck, the mic's are 20++ years old,


** Still within the useful lifespan for Shure vocal mics that get low usage.


so I guess
I've gotten my money's worth out of them.


** I disagree and think the foam wind sock disintegration is a separate issue to the mics going silent.


I understand that electrets can become depolorized
but never thought dynamics would/could go bad just
sitting in a box. Live and learn.


** Fine copper wire, as normally used for voice coils on mic diaphragms, corrodes under damp conditions and develops opens.

However, Shure mics like the SM57 & SM58 use much thicker wire for the voice coils followed by a step up transformer which goes a long way to extending these mics lives.



... Phil


Damn, I hadn't thought to check for an open voice coil.


** Not a lot else makes a dynamic mic go silent.


Yep, they both measure as open. Corrosion of the super
fine wire is quite the logical explanation.


** I think Klay Anderson's advice is worth taking.

" Send them back to Shure. Theyll give you new ones for the price of repair or better. "

Shure may just send you two new SM-48s.



.... Phil