Ocean noises- Is my mic dead?

[madmax25]

So I picked up a Rode NT1 (the older model) a month or so ago on eBay. All was well and good and I've recorded with it a few times since. I plugged it in the other day and noticed after about 3-4 minutes it starts making nasty noise, kind of like the "ocean" noises that come out of broken tube amps. Or like the noise floor suddenly goes thru the roof or something.

Anyone have any pointers on what I can do? How to pinpoint where the problem is? If it's a dead cap or something I'm handy with a soldering iron, I just need to know where to look...
Help!

[ausrock]

It could be condensation on the capsule causing the problem which can usually be corrected without resorting to a soldering iron. The easiest way is to place the mic under a desk lamp, etc., approx., 4" - 6" away, use a lower powered light bulb (eg: 40 Watt) so that the mic is exposed to a gentle warmth NOT too hot and leave it for as many hours as possible. If moisture was present, this should dry it out.

Always store your mics with some desicant nearby (little sachets of Silica Gel).

If the problem hasn't been fixed, then start looking for problems deeper in the mic. Of course, based on the info available, it is possible that the problem is elsewhere in your system..........but I presume you've narrowed it down to the Rode.

[madmax25]

Yeah, it's definitely the mic. Thanks for the advice. I'll try that. I have a bad feeling it's not moisture though...

[antichef]

Is there any good signal coming through the mic?

I had ocean noises coming from one I bought used -- turns out one of the wires to the XLR pins was off (I think it was pin 3). I get very similar Ocean sounds when I turn on and off phantom power with no mic attached.

[PhilGood]

This can be caused by several different things. I can be a bad capacitor, flux on the circuit board, a wire that is dangerously near ground or almost shorting, or a dirty capsule. High impedance circuits are very picky about everything being just right. If not, they start leaking current across weak spots and that's what your hearing.

Do not try to clean the capsule yourself unless you know exactly what you're doing! You can ruin it!

There are folks who know how to do that if it's the problem, but look elsewhere first. It could be something very simple.

[madmax25]

The capsule doesn't look too dirty, and I don't think anything is wired bad...
the fact that it sounds great for 3 or 4 minutes and then the storm hits makes me think it's probably a dead cap? It warms up then starts passing current to places it shouldn't, right?
if so, any reccomendations on how to start hunting the bugger down?

thanks for all the help

[PhilGood]

Well, you'd have to start replacing the caps one by one until the noise goes away. It might even be an FET, since it happens 3-4 minutes after it warms up.

[Rimshot]

What's FET? That's a term I haven't heard before.

[PhilGood]

Originally Posted by Rimshot

What's FET? That's a term I haven't heard before.

Field Effect Transistor.

[madmax25]

hmm...i asked my dad about it just now. he works in the semiconductor industry and his guess was something involving a transistor, so you might have hit it
I'll do some digging with that. Thanks a bunch man.