rockinrob86

I repaired a Beyerdynamic M500 -saved the ribbon!
« on: April 28, 2019, 10:59:44 AM »
No one in my real life understands this achievement, so I thought I would brag/reveal my methods here.

I got a good deal on a pair of these, and assumed something was up as I got two for way less than 1 would be.

Anyways, got the mics and 1 worked great, 2nd one was super thin sounding - it sounded like it rolled everything off below 300hz

Started taking the 2nd one apart, and the ground from the transformer wire was broken.  Soldered it back, mic still sounded thin.

Took a look at the ribbon through the filtering, and it looked visually fine, and appeared clean.   I ended up popping off the filter assembly, and when I did this (the glue wasn't holding at all anymore, it revealed glue residue all over the magnets, at least I think that's what it was.  It was a fine rust colored powder.

I proceeded to carefully scrape the top of the magnets with an exacto knife blade, which got this powder everywhere, but cleaned off the residue.  I then took some rolled up strips of painters tape, got under my super bright shop light, took a deep breathe and more gently than I have ever done anything, lightly tapped the roll of tape into the gap and just kissed the ribbon with it.  I also turned the mic upside down and tapped gently on my workbench.

I got a new tape roll every 3rd or 4th tap, and after about 10 very gentle go rounds, I still hadn't broken the ribbon.  Plugged the mic up, and the bass was back, but it was a bit distorted sounding because I hadn't added the filter back. 

Turning my attention to the filter, I used the exacto knife's backside to carefully pop the screens off the plastic (the glue was brittle and easily removed.  Inside the filter, there is a clear plastic baffle that actually covers the ribbon entirely - this blocks breaths from destroying the ribbon.  This filter had become detached, so I used a drop of CA glue on each side and held it in place.  Then, I finally used a drop of fish glue to secure the screens back in place. 

After the glue dried, I put the mic back together, and it sounds fantastic!  These are really nice ribbons.  I'm uploading a video of a demo track I did soon to show off this mic.

Post op - micro dust debris in the gap and on the ribbon can restrict movement and negatively impact the frequency response of these mics.



EmRR

Re: I repaired a Beyerdynamic M500 -saved the ribbon!
« Reply #2 on: April 28, 2019, 03:06:31 PM »
Nice save!
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

tchgtr

Re: I repaired a Beyerdynamic M500 -saved the ribbon!
« Reply #3 on: June 01, 2019, 01:18:44 PM »
Congrats! Great mics. I have two, and sent one to Samar for repair after replacing the ribbon myself. Sounds much better with the original ribbon material.
Resistance is not futile. It is voltage divided by current.  (thanks, Bill)


 

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