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Re: Tips DIY for Primo Em172

Subject: Re: Tips DIY for Primo Em172
From: "" gmo_du=
Date: Sun Sep 16, 2012 11:16 am ((PDT))

The photo of the 'kit' shows that the mic capsules have no wires attached.
A soldering *gun* will be so huge in terms of size and heat that it will in=
deed destroy the capsules.

You need a very small iron, about 10 - 15 watts, preferably temperature-con=
trolled, with a miniature conical tip. Use high grade, low melting point so=
lder. The cost of this could easily be 3 - 5 times the cost of the mic kit.=
 But you'll have a good tool to construct future cables and rigs.

There is no "foolproof" method of soldering. You must learn the technique a=
nd the practice,practice, practice! If you have not done any fine work of t=
his sort, it may be best to just have a professional do it for you. You can=
 also have them teach you and help you out while you do it. Otherwise you m=
ay have cold solder joints or ruin the capsules. Perhaps there are some tut=
orials on YouTube.

In a nutshell, here is the technique:
1) heat the soldering iron to about 600 - 700 degrees Fahrenheit.
2) apply solder to the tip of the iron to coat it. This is called 'tinning'=
. Then wipe the tip off on a moistened ( not "wet") sponge and re-apply a t=
hin coat of solder. Do the wiping/tinning process each time before solderin=
g a wire.
3) strip the wires ends appropriately to the length required, which depends=
 on where they are being soldered. In the case of the mic capsules, the bar=
e wire length should be about 2mm long, shorter than each solder pad on the=
 mic so that you do not end up with short circuits!
4) tin each bare wire end by applying the iron tip from under the copper wi=
re and apply fresh solder to the top of the wire until it melts and flows f=
reely. Remove the applied solder from the wire as soon as it coats the copp=
er. Be careful not to melt the insulation of the wire. Remove the iron form=
 the wire as soon as it has been tinned properly. When the wire cools down,=
 check it to see if the tinned length is still correct. If it is too long, =
use a small pair of diagonal cutters to trim it back to the correct length.
5) make sure that the iron is now clean and tinned properly. Bring the wire=
 end close to the capsule. Have the capsule held securely in a small bench =
vise with rubber jaws, but adjust the force to just prevent the mic form mo=
ving. Don't crush the mic and have the solder pads facing upward. Apply the=
 iron tip to the top of wire to melt the solder on the wire as you bring th=
e wire down onto the pad. As soon as the pad solder melts, the wire should =
be as far down onto the pad as it can get. The moment that the solder flows=
 freely one the pad and around the wire, remove the iron and keep the wire =
end *absolutely* still until the solder cools. The solder joint should look=
 shiny, not dull. If it is dull the you have what is known as a 'cold' sold=
er joint which is a bad connection and is mechanically poor. If this happen=
s, you need to take the wire and remove it, clean the wire end  and the pad=
 with Solder Wick and start over. But you must be very mindful of how much =
heat to use each time you do this. The idea is to use enough heat to do the=
 job quickly, but not enough to damage the mic pads or the element. The pro=
per technique is developed only through practice and experience. Again, fin=
d a tutor or have it done by an experienced person that has the right tools=
. BTW, don't nick the wire when you strip the ends!! If you do that, it wil=
l break off and sever the connection at some point. If you do nick the wire=
, cut it off at the nicked point and re-strip the end.

There are many more things that can be said about this process, but just pr=
acticing on junk with various pieces of wire is important. There should be =
other resources on the web for this. Remember to buy good miniature hand to=
ols and but a high quality soldering iron and solder.

As for what wire goes where, well that is something that should be included=
 with the kit.

Good luck with your project! I hope that I have given you some insight into=
 the process.


Sent from my iPad

On Sep 16, 2012, at 12:05 PM, Peter Shute <> wrote:

> The EM172s I got from Frogloggers already had short leads attached, and G=
ene said he doesn't attach them, they just come like that. Perhaps yours wi=
ll have them too when they arrive, and you won't have to solder them direct=
> Peter Shute
> --------------------------
> Sent using BlackBerry
> ________________________________
> From: 
> To: 
> Sent: Mon Sep 17 01:46:31 2012
> Subject: [Nature Recordists] Tips DIY for Primo Em172
> Hi All,
> Recently ordered DIY kit for the Primo em172 from FEL ( http://www.micboo= )
> in the UK to ship to my location here in Vietnam. Have a standard one set=
ting soldeting gun and I know there was some discussion on how not to overh=
eat the capsules. My soldering skills are minimal at best. Any tips on how =
best to gauge overheating those capsules? Or >foolproof< techniques to make=
 sure I don't?
> Cheers!
> Mark

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