I recently got a Sterling Audio ST55 for free cause the previous owner noticed a high-frequency flutter in the signal. The mic still works for the most part, but the flutter definitely dulls the transients and screws up the presence frequencies in recordings. I'm trying to learn more about electronics/electronic repair so I am coming here for some advice on the repair.

At first glance, it appears that some of the connections from the XLR insert to the main circuit board are worn and one connection looks particularly suspect. I am attaching photos of the suspect connection as well as the photos of the circuit from the recording hacks website. The connection of the red wire is the one I think is suspect. I will try to upload better photos soon. My questions are as follows:

  1. The connection looks like it is still making contact, but it almost looks like the wire has frayed. If I were to go about repairing this, how should I start? Should I desolder the connection and strip back the wire a little more to make a new connection?
  2. In your experience, could this high frequency flutter be a result of a faulty XLR connection? Or is it more likely a failure of one of the other components of the microphone? How could I go about testing the other components to diagnose the problem if it is not just the XLR Connection?

I've attached photos of the mic. Thanks in advance for your help.

[ST55 Article in Recording Hacks Microphone Database] http://recordinghacks.com/microphones/Sterling/ST55

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  • 1
    I don't have anything like the circuitry know-how to know if it will fix it, but the white wire looks like a dry joint, the red looks like someone previously attempted a very poor [read: totally clueless, didn't even tin it first] re-solder. You could do worse than re-flowing both, properly. Also, it's a bit out of focus, but it also looks like whoever did the ham-fisted job on those wires has also made a bo££ocks of the top two resistor joints while they were at it. You're probably going to have to inspect any other areas that show re-heating, like the melty/white spills round that area. – Tetsujin Sep 4 at 17:05
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    Even harder to be sure, but the left leg of those two diodes looks suspect too. Maybe they were soldered on the back face, but you'd expect to be able to see some flow through. Compare to the 'official picture' - the solder should be bright & shiny & 'stick' up the component leg/wire. If they're dodgy joints I don't think we can lay the blame at Mr HamFist, that would be factory error. – Tetsujin Sep 4 at 17:17

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