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Bogdan

Travelling kit for ambient recording (silent source)

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Bogdan   

One simple question (and other related questions):

Does humidity damage LDC mics permanently? (or similar fragile mics)...

or....  Does humidity damage these mics gradually.... over a (very) long time of exposure to humidity?

or... Humidity affects these mics temporarily. Meaning, if I travel in a misty/humid place, I could record with them (albeit noisy), but as soon as the air dries, these mics will come back to their noiseless state, with no harm done.    ?

And..same question(s) as applied to temperature.

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I modified some off-brand LDCs in the past with the Scott Dorsey circuit which replaces the Hi-Z amp with a good quality FET transistor.  The input impedence of the FET was 1000 MegaOhms, i.e. 1GigaOhm.   The original circuit had a mere 200MOhm resistor.   After soldering the parts to the board, it took several attempts with the cleaning fluids to get the mic to work - any contaminents caused leakage and thus reduced the output level signficantly.   Moisture has the same effect.    Drying out should certainly revive the mic, unless the filament of the condensor itself has warped.

I believe the quality of the early Neumanns had a lot to do with the attention to detail paid when tensioning and screwing down the gold foil to the mount.

Prolonged/Severe moisture has the extra problem of seeping into the screw threads holding the filament tight, at which point the microphone will not revive its previous specs after drying, because of uneven warping.

If you are expecting to be in humid environments, going downscale on the microphone and carrying a backup might be a good idea.

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DanieldH   

My initial thought on keeping stuff dry: Silica gel works but is expensive/not widely available. Keep a small bag of cat litter in your vehicle. Put your sensitive equipment in a dust-tight but air transmissive bag (thick cotton/GoreTex? I'd guess you could throw money at Kortwich or your local taylor, but I'd go the DIYroad) and this inside the cat litter. Side effect: Any burglar will ignore the cat litter and what's buried inside. To prevent your "drybag" from continiously soaking humidity every dewing morning use some plastic garbage/shopping bag. Some cheap laundry box is also an option and makes digging more comfortable but might cause "interesting" situations at border crossings. Monitor the situation with some cheap hygrometer.

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Bogdan   
On 02/05/2017 at 1:07 AM, DanieldH said:

Side effect: Any burglar will ignore the cat litter and what's buried inside

Any burglar reading this will become a cat litter treasure hunter :)

Well, maybe my joke isn't funny. Yet, I've certainly never thought of this unusual strategy. Thanks for inspiration!

It makes sense to cover expensive gear in repulsive bags when travelling forever:)

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