Troubleshoot: Random Popping Noise on Condenser Mic

[firstdivision]

Hi,

I've started getting a random popping, or thumping, while recording with my condenser microphone (can't remember the model, but it's similar to the Beyerdynamic Opus 53). The chain is like this:

Mic > XLR > Presonus Tube Pre > XLR > pc interface

I can eliminate the noise if I use my SM58 (the only other mic I have) so I've come to the following possiblilties:

- There is a problem with the condenser mic itself, or
- There is a problem with the phantom power supply in the Tube Preamp, or
- There is a problem with one of the cables carrying the phantom power

Can anyone suggest which is more probable, or offer another alternative so I can start down a troubleshooting path?

Thanks,
Andrew

[A-Barr]

Do you know anybody with another rig where you can try the mic out? That would narrow it down to your preamp or the mic. Doubt it's the cable if the 58 is fine.

[Jess P]

I was trying out a KSM27 that I was thinking of buying from a guy and when I plugged it in it sounded like the ocean. He had it in his car for a couple 100+ degree days and it damaged the actual condencer.

I'd take the mic down to a local music store and ask if you can plug it into a mixer and listen to it. Then you'll know if it's your mic or your pre.

[drumsound]

Upi might also swap the cable. The phantom may not be getting to the mic correctly due to a short that might not reveal itself on the dynamic mic.

[thunderboy]

Definitely check the cable thoroughly. An intermittent short on any conductor could cause this problem. Otherwise, my money is on a short in the mic itself.

jt

[firstdivision]

Hi,

Thanks for the suggestions, I think I'll stop by the music store on my way to work tomorrow and see if they have something I can plug into.

The cables have been around for longer than the mic, which is relatively new. To test the cable, would I just need to check for continuity between two of the pins which would indicate a short inside the cable somewhere?

[SpencerBenjamin]

Well, there are cable testers which do the job for you, or the painful way is to first check continuity between successive pins at m/f end, then systematically check there is NO continuity between each pin & the others, which would indicate a short.

Do you have another mic which uses phantom power that you can use in the chain? For some reason that's my gut instinct, that there's an issue with the +48v power, but my gut's not particularly reliable.

[Roboburger]

some condenser mics just don't wanna grip the pins on some cables right, change the cable and you will prolly be fine. I have that problem with a load of phony Neutrik ends I got off ebay. all dynamics work just fine, but AT condensers won't fit on the ends, and two of my phantom power DIs act sketchy on those cable ends. Gonna resolder a bunch over the club's xmas break.

[thunderboy]

Ah, yeah - I always have problems with Switchcraft connectors being too loose. A lot of variables to sort through.

jt

[Roboburger]

+1 on the switchcraft comment above.

[Jess P]

What was the vedict? (if any)


I need closure.

[firstdivision]

Hi all,

Sorry for the lateness of the reply. Through some creative hookups I was able to determine that (within 90% confidence) it was the microphone itself that was generating the noise.

It took me a while to scratch together the time and funds for a new microphone, but I eventually did (a nice large diameter condenser). I got home, plugged it in, and voila! Crystal clear! (I also bought new cables for good measure, but my initial test I used the old ones to not introduce anything new.

Now that I knew the other microphone was the source of the noise, my curiosity got the better of me and I decided that a disassembly was in order. I took pictures along the way and posted the whole ordeal to my site. Among the revelations? You don't actually need a pipe cutter to take the microphone apart. LOL

Here's the link to the text (which has links to the pictures of the exposed microphone): http://blog.killfly.com/index.php/2007/ ... sassembly/

Thanks for all the replies!

-Andrew

[JWL]

It could be a bad cap somewhere in the mic. I've heard of bad caps making popping sounds as they charge/discharge.

Maybe look at all the solder joints for the caps, make sure there are no cold solder joints?

[firstdivision]

That was my guess too, just based on my experience with motherboards in PCs. Too late now though, my "disassembly" resulted in basically destroying the microphone. I did look at all the connections on the board of the mic though, and hey all looked fine to me. So I was thinking the insides of one of the caps had failed (kinda like they did on a lot od Dell motherboards).

The other hint towards the cap was that it would be ok when the mic was first turned on, and then get progressively worse.

[SpencerBenjamin]

Aah, you didn't tell us it was a behringer.

*Shakes fist towards the sky*

DAMN YOU BEHRINGER...!!!