Magn=FAs,
I've got the old MKH400 series mics some of which date back to the
1070's and they are very robust. Current models are a slight
improvememnt over what was always good specs but perhaps not quites as
robust.
> Is it mainly capsule or circuit problem?
Condensation or liquid water will always cause problems and if a mic
gets wet or damp, it is probably unwise to heat it up (as with any
electronic gear) as that can drive moisture deeper. Let wet gear dry
slowly in a dry place. I've just written about silica gel and I sue
woollen cloth which has been freshly ironed or heat dried.
MKH series mics use a lower voltage across the capsule and a high
frequency bias instead. This has two benefits - less likely to "track"
across moisture, and a low impedance. Other mic capacitors have a very
high impedance in the hundred of megohms, so the slightest leak gives
trouble.
An old trick with screw-in capsules is to wipe silicone grease over
the insulators.
> Does the circuit board have lacquer coat or not?
All PCB's have a coat but for the best protection, the assembled
circuits should be "tropicalised" over the plugs, components and
solder joints as well.
I once had a Nagra IV tape recorder swamped by sea water while filming
open boat whaling in the Azores, and I got the batteries out within
seconds. I stripped out all the circuit board san washed them in fresh
water and is worked on until displaced by stereo and digital years
later.
> Are some sealing around capsule and XLR ends?
Not around the capsule as the sound has to get in. This is the weakest
point as the diaphragm has to be the thinnest possible. Electret
capsues are the most vulnerable as if any damp diffuses through the
capsule diaphragm(s), it can dischange the electret and kill the
capsule.
Plugs are often not waterproof, but are reasonable resistant to
splashing but not immersion unless they are designed to be immersed..
> Are the switches waterproof?
No, unless they have a gland or sealed rubber cover. If the switch
contacts get corroded they will give endless trounle.
> If using isolate tape over the switches (and probably around XLR
> too), would it be the key of trouble free recording in wet
> conditions?
Taping up plugs and switches is a good idea in wet locations but it is
not foolproof, so take it off as soon as you are dry again.
David
David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce
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