source for plastic sleeve / bushing for diaphragm leads to pass through top plate of mic body?

[klem]

the holes are ~2mm in diam, and whenever the terminated capsule lead touches metal, noise rears its ugly head. at least it's interesting noise though. i still need to do some better cleaning with isopropyl, but seems like this is a no-brainer to add as well, if I can find it.
anybody got some spares, or suggestions on where to source them? Or maybe just some silicone filling the hole, then drilling a hole to pass the lead through it down to the PCB?

i also wonder about adding a layer of heat shrink to capsule lead to help better insulate, but what if that makes it more microphonic to the mechanical movements? I don't relish trying to replace a lead like that, at least not on the fancy capsule i have. plastic bushing is far less of a risk...

 

[Khron]

I know they make insulating washers (nylon) for the mounting screws (M3) for TO220 packages. Either see if they happen to make those for ~1.5mm screws as well, or just drill out those holes to ~3.5mm, to fit those standard washers.

https://duax9x73a20d1.cloudfront.net/storage/products/2017/09/14/0qrl0gddpjqt8r4m.jpg

 

[EthanSpaulding]

"Shoulder washer" is what you might want. You may have to drill it out, like Khron is suggesting.

https://www.mcmaster.com/shoulder-washers/

 

[abbey road d enfer]

I would just put a drop of silicone putty to prevent the wire from moving.

 

[shabtek]

the rtv silicone for electronics not the silicone for sealing windows

 

[klem]

Since I've already soldered the connection for this FET47, sounds like RTV silicone is the way to go. Still, I'll grab some shoulder washers for future builds. Thanks all for the helpful advice!

For a belt and suspenders kind of guy, what do you think about adding a layer of 'very flexible' heat shrink to capsule leads?

 

[ccaudle]

the rtv silicone for electronics not the silicone for sealing windows

Just to emphasize what shabtek pointed out, when you use silicone sealant that is made for general household use, you can smell the acetic acid released as it cures. Acid fumes wafting through your new microphone is not what you want.

 

[shabtek]

I have made bushings with silicone sleeving inside /hellerman sleeves for this application

 

[abbey road d enfer]

For a belt and suspenders kind of guy, what do you think about adding a layer of 'very flexible' heat shrink to capsule leads?

Almost by definition, heat shrink is not flexible.

 

[klem]

Almost by definition, heat shrink is not flexible.

Maybe it's semantics, and I'm not here to quibble, but there are multiple manufacturers that define/describe their product as "very flexible" (literally in the title of attached). Here it is at DK if attached pdf doesn't load. IME, it has indeed stayed very flexible once shrunk.

 

[abbey road d enfer]

I've only used the standard heat shrink. Bought a stash in the 1990's and think it will last till the 2030's, if I'm not dead before.

 

[klem]

Ha, I definitely have quantities of some things that will probably outlast me as well. It's hard not to become a packrat with this hobby/addiction.