sE X1 Repair

I've never had a problem - normally any water will be azeotropically removed by the evaporating solvent. But you can just quickly (and carefully!) remelt the solder on the joint - that will drive off any solvent and moisture, and hopefully if you are careful you won't need to clean again... ;)

Hi Paul! Nice to be seen!
 
Thoroughly removed previous solder attempts and redid, looking much, much better, with same sonic result. No ground hum at all, the tiniest of tiny signals buried in noise when turned to high gain.

Some history might bring clues at this point:
When I bought the mic (second hand) the cage was badly dented (hence easily bargaining a throwaway price) and like a twat I got excited and went to mend the cage before I'd tested if it worked :facepalm: . On putting it back together I slipped and popped the wires off.

Should I be putting it down to previous (possibly shock) damage that is causing the ghostly low signal and be investigating from there?

Champion replies btw really really appreciated.
 
Yes, it could be previous damage if it has never worked for you. Probable issues would be the capsule itself, or the FET being bad or misbiased.
Can you post photos of the capsule and of the circuit board from above, showing the components? And also showing the connection of the black wire.
I assume that the cable and phantom power are good.
 
After some wrestling with the camera...
 

Attachments

  • 2013-04-13 05.33.36 Diaphragm.jpg
    2013-04-13 05.33.36 Diaphragm.jpg
    5 MB · Views: 85
  • 2013-04-13 05.37.17 PCB Top Down.jpg
    2013-04-13 05.37.17 PCB Top Down.jpg
    4.8 MB · Views: 104
  • 2013-04-13 05.38.42 Red Con.jpg
    2013-04-13 05.38.42 Red Con.jpg
    4.7 MB · Views: 79
  • 2013-04-13 05.40.30 Black.jpg
    2013-04-13 05.40.30 Black.jpg
    4.8 MB · Views: 78
  • 2013-04-13 05.41.58 Black.jpg
    2013-04-13 05.41.58 Black.jpg
    4.9 MB · Views: 95
Right, I am about to pack in for the night, but, from your pictures, as far as I can see...

It looks like the red wire is attached to the capsule polarisation supply, and the black wire is grounded to pin 1 of the XLR. There is no signal going to the gate of the FET (middle pin).

Are you 100% sure the wires are in the right places? I am not. And it looks wrong, having the two wires so far apart when there is another earthing point near by. Looks wrong and feels wrong.

There are lots of ways to polarise a capsule and pick off the signal - my guess is that they have used this kind of arrangement, a variation of the Schoeps circuit...

http://wavebourn.com/images/audio/Wavebourn-MXL770-V3.gif

So, I would try connecting the black wire to the gate (middle pin) of the FET. That is the other teflon standoff.
Leave the red wire as it is.

Try that.

If it works you need to check the polarity of the mic - if the red and black wires are reversed then the mic will be out of phase.

Capsule is dirty btw, but don't try to clean it.

Let us know how it goes!
Stewart
 
You must log in or register to reply here.
Back
Top