Topic: Problem: DPA 4060 sensitivity/output dropped by 10-12db?

[Gutbucket]

Yestereday the output of one my DPA 4060s dropped by about 10-12db.  After correcting the level on playback, the frequency response still sounded balanced in a quick listen.  I checked to make certain the issue was with the the microphone by switching preamp and recorder channels and comparing with my other three 4060s.

The mic appears clean and unblemished.  I suppose I could do the distilled water swizzle to clean and plug-in power to dry trick, but there is no visible contamination of the inner gold capsule or its tiny orifaces, so I'm skeptical that will accomplish anything.  I suppose I'll need to contact DPA in Denver, but I thought I'd tap the TS knowlege base first.

I'm wondering if anyone else has experienced something similar and if this is a typical failure mode of these mics.  This is a matched pair I bought new in 2006 through Frank at the now defunct Cascade Media, so they are about 3-1/2 years old.

Thanks.

[boojum]

I can't help, Lee.   My '61's are yet young and still equal.  I will be watching to see where this thread goes.

Good luck!

[mfrench]

-10->12dB is indicative of a fried FET - sorry to say (been there, done that).
Does the wav form show any odd spikes anywhere?

[Gutbucket]

I'll check that as soon as I get a chance.  Thanks for the heads up.

[boojum]

How do you blow an FET?

[mfrench]

How do you blow an FET?

Extremely tight tolerances - microscopic.  Electret capsule meets backplate, ZAP goes the FET!
I've not heard of it happening so much with the 406x series, but have seen/heard of the same symptom (10-12dB off) in some other models.
Hopefully I'm wrong.

[boojum]

Mike, that sounds as if the '60 was overdriven.  Would that be the case???


BTW, how's the rain down there?  Has it subsided?

[headroom]

if the FET was blown the mics would be dead silent it hapend to my once. And one time one other mic hade a more noise after a few month  then the Stereo brother. DPA Denmark  refused to help:  the mic is ok! Tried a year later again my DPA Seller Gotham Switzerland and this time the answer was no warranty anomore! And I dont want to repeat the words he put on me...

[mfrench]

if the FET was blown the mics would be dead silent it hapend to my once. And one time one other mic hade a more noise after a few month  then the Stereo brother. DPA Denmark  refused to help:  the mic is ok! Tried a year later again my DPA Seller Gotham Switzerland and this time the answer was no warranty anomore! And I dont want to repeat the words he put on me...

Not necessarily.  They die in different ways - though my experience is more related to the compact and full size SD series.  My 4060's have been rock solid so far - knocks on wood.
I'm sorry to hear of your episode with them. This sounds like what we had to deal with, early on.  DPA North America is a very refreshing version of representation, as compared to what was available here in the late 80's, when we were truly on our own with the things.  The representative entity here in that day was wretched, and really damaged their reputation early on (B&K). 
DPA N.A., and Bruce Myers have worked incredibly hard to change that.

[mr qpl]

qft Bruce is very helpful. My 4061's are running well after 5 years of my ownership.

[headroom]

I have 2 beautefull dead FETs white DPA 4060 Mics. Did some on know how to make a good surgery for opening?  Doesent matter cutting off the wires. They are embedded in Epoxy I think.