Topic: DPA 4060 ebay ex-theatre mics very noisy - are they fried?

[dogmusic]

I bought a pair of ex-theatre DPA 4060's off ebay. I did read the warnings on this forum beforehand, as well as reports from some satisfied buyers, and decided to take a chance.

They came with no connectors, and although I'm a rank amateur with a soldering iron, I managed to get a 3.5 mm stereo plug on the end and test them out.

My SONY M10 didn't seem to have enough juice using plug-in power, while plugging the mics into an SP-SPSB-8 battery box and going line-in wasn't a whole lot louder. Going mic-in (no PIP) with the batt box was louder still but sounded noisier on one channel and also had some distortion.

I then went mic-in to a SONY D50 using plug-in power and got very good level. However, the mics seem exceptionally noisy. Although there is no distortion and it's a good recording, there seems to me to be an awful lot of hiss.

Here's a sample recording of some percussion sounds about 24" from the mics. [DPA 4060'S > SONY D50, mic-in PIP, record level 5.0]

http://www.box.net/shared/7tvtagxsm9hsfsu6329e

Could this be the result of a lousy soldering job? Or are these mics burned out?  Or is this typical of DPA's?

Or do I need to clean them as I have seen suggested here? If cleaning is the answer, could someone who has done that to a pair of DPA 4060's please lay out the procedure for me? I'd hate to make matters worse!

Also, is the plug-in power of the D50 rated higher than the M10? Has anyone had success with DPA's going mic-in PIP to the M10?

Any advice will be greatly appreciated.

Thanks,

Phillip

[dogmusic]

The amplitude and spectrum of the noise signal from the two mics is practically identical--that's a sign the mics aren't toasted because they would not be likely to fail in exactly the same manner.  It's not a bad solder job, that's a work/doesn't work/works intermittently issue.  That leaves either something incompatible with connected equipment (insufficient power, excessive load, improper gain staging, etc.) or that's just the way they are.

I don't know how loud your percussion was at the capsule so I can't speculate on the indicated self-noise of the mics.

Thanks for your detailed reply. I'm surprised that the plug-in power of the D50 worked better than the battery box > M10. And I have a pair of AT853's that I use with that same battery box, line-in to the M10, and get much more volume and less noise. Do the DPA's need more power than the AT's?

The percussion was not very loud. Is there a better way of doing this test?

[Church-Audio]

If you look at the common connection between these two mics you have three things to consider.

1 Bad ground from the sheild to the 3.5 mm stereo jacks
2 Bad or weak battery. Low bias supply usually results in highly distorted audio but can also lead to noise.
3 Bad mics

Its possible to have two bad mics especially if they come from a theater. I have said this time and time again as a live sound engineer I know what I am talking about. NO THEATER sells perfectly good working DPA microphones unless they are :

A Closing down
B something is wrong with that mic so they want to get rid of it.

Now if you dont have another perfectly working DPA to compare it to you might now notice a lack of top end. Because you dont have a valid reference point. But when you do like I do with my DPA 4007 Or my THE measurement mics. Then you begin to see the effects of a sweated out mic. And believe me before any mic gets sold they try all the tricks they know to get it back to proper fuction. So yes you can have two bad mics one of the major symptoms of a bad DPA 4060 OR 61 Is noise.

[dogmusic]

If you look at the common connection between these two mics you have three things to consider.

1 Bad ground from the sheild to the 3.5 mm stereo jacks
2 Bad or weak battery. Low bias supply usually results in highly distorted audio but can also lead to noise.
3 Bad mics

Its possible to have two bad mics especially if they come from a theater. I have said this time and time again as a live sound engineer I know what I am talking about. NO THEATER sells perfectly good working DPA microphones unless they are :

A Closing down
B something is wrong with that mic so they want to get rid of it.

Now if you dont have another perfectly working DPA to compare it to you might now notice a lack of top end. Because you dont have a valid reference point. But when you do like I do with my DPA 4007 Or my THE measurement mics. Then you begin to see the effects of a sweated out mic. And believe me before any mic gets sold they try all the tricks they know to get it back to proper fuction. So yes you can have two bad mics one of the major symptoms of a bad DPA 4060 OR 61 Is noise.

And yet there are some people on this forum who have had good experiences buying these theatre DPA's.

[Church-Audio]

If you look at the common connection between these two mics you have three things to consider.

1 Bad ground from the sheild to the 3.5 mm stereo jacks
2 Bad or weak battery. Low bias supply usually results in highly distorted audio but can also lead to noise.
3 Bad mics

Its possible to have two bad mics especially if they come from a theater. I have said this time and time again as a live sound engineer I know what I am talking about. NO THEATER sells perfectly good working DPA microphones unless they are :

A Closing down
B something is wrong with that mic so they want to get rid of it.

Now if you dont have another perfectly working DPA to compare it to you might now notice a lack of top end. Because you dont have a valid reference point. But when you do like I do with my DPA 4007 Or my THE measurement mics. Then you begin to see the effects of a sweated out mic. And believe me before any mic gets sold they try all the tricks they know to get it back to proper fuction. So yes you can have two bad mics one of the major symptoms of a bad DPA 4060 OR 61 Is noise.

And yet there are some people on this forum who have had good experiences buying these theatre DPA's.

Yeah because some of the guys working in theaters are MORONS. And they think somethings wrong with the mics they are unloading so they dont care. Or there are issues with the mics its just that nobody can hear the difference because like I said if you dont have a properly functioning DPA to compare it to it would be difficult to hear issues. But that does not mean they are not there. Any way you slice it, its a gamble.

I dont think a rational person sells a $500 + mic for $100 in this economy unless there is something wrong with it or they are desperate for cash.....

[yousef]

I think that sometimes the cosmetic condition of the mics influences how the theatres think of them - mine looked rough - covered in dried glue, traces of make-up etc but all the key parts were in good condition and after a clean with distilled water worked perfectly for 5 years.

One of them has just become about 5dB less sensitive than the other and so has had another dip in the distilled water - even if that doesn't bring it back to spec I reckon I got my money's worth for the service they've given me.

But how you would tell the difference between a good and bad mic before pulling the trigger on Ebay, I don't know.

[dogmusic]

I think that sometimes the cosmetic condition of the mics influences how the theatres think of them - mine looked rough - covered in dried glue, traces of make-up etc but all the key parts were in good condition and after a clean with distilled water worked perfectly for 5 years.

One of them has just become about 5dB less sensitive than the other and so has had another dip in the distilled water - even if that doesn't bring it back to spec I reckon I got my money's worth for the service they've given me.

But how you would tell the difference between a good and bad mic before pulling the trigger on Ebay, I don't know.

Can you please describe the steps in cleaning these mics? Do the mesh metal screens have to be removed? How much time did they spend in the distilled water? How do you dry them?

[Church-Audio]

I think that sometimes the cosmetic condition of the mics influences how the theatres think of them - mine looked rough - covered in dried glue, traces of make-up etc but all the key parts were in good condition and after a clean with distilled water worked perfectly for 5 years.

One of them has just become about 5dB less sensitive than the other and so has had another dip in the distilled water - even if that doesn't bring it back to spec I reckon I got my money's worth for the service they've given me.

But how you would tell the difference between a good and bad mic before pulling the trigger on Ebay, I don't know.

Again nobody gets rid of perfectly good working mics. NOBODY and cosmetic does not factor into it at all. Why because these mics are always hidden on a performer where you cant see them like in the wig on top of the head ect. Distilled water works well with 100% isoprophanol. Again you dont have a good working DPA 4060 to compare it too so you would not know if they were working correctly no offence.

[yousef]

Contradicting yourself a bit there, Chris. I was suggesting that the "morons" you spoke of earlier might think that the cosmetic condition of the mics reflects their functionality and hence influences the decision to dump them.

You're right, I don't have another set of mics to compare mine with side-by-side (although how you knew this, I don't know  ) but I've heard an awful lot of DPA4060/4061 recordings and I can't say that I can discern an obvious qualitative difference between my results and those with, say, Coresound HEBs. And certainly not a difference enough to tempt me into the extra spend.

[adrianf74]

My $0.02 here: I have a pair of ex-theatre mics.  I used them at a Casino show this past Friday without issue and it's probably one of the best pulls I've ever made (save for the three wooks behind me during the first four songs).  Period. 

My 4061's were sold to me by a very well-respected veteran on this board who got the pair in a gear trade and was trying to help me out in my search for a "reasonable priced" pair; besides, he already had a pair of DSM-6's and didn't see the need for both.  The original person who had them bought them, cleaned them, and then re-terminated them at 1/8" and never really liked the way they sounded so he traded them off.  This person is also well-versed in their opinions of DPA mics and how they prefer a couple of other brands mics to these.

But back to the point, Chris.  Not all mics that have been bought off FleaBay (from wherever) are toast.  Many people on this board have bought their mics off FleaBay without incident; CheeseCadet is among them, IIRC, and has made some killer recordings (his Howie Day recording from September was pretty incredible if you ask me).  The issue many of us come across (myself included) is that the mics are NOT MATCHED (a la CoreSound's HEBs) but does this mean that it's better to buy those at 2, 3 or 4x the price?  Likely not.  In my case, I have a 2dB difference between the left and right channels (which I can either fix in post or buy an Ugly preamp to resolve -- if you ever get back to me that is).  The mics on FleaBay sometimes have a problem with the connector on them which can be resolved by re-termination but, more often than not, the theatre is just cycling stock to ensure that they don't have the mic totally f-up on them when in use.  Let's be honest, they don't have to run them totally into the ground with the prices of tickets; cycling gear is just a cost of business.  Several people on here have also put me in touch with a few reputable sellers of said mics on FleaBay but none of them had black mics (which was what I was looking for).

That said, Chris, you're making a very blanket statement and one-size does not fit all in this case.  It sounds like the OP might have gotten some bum mics but it's hard to know for sure unless somebody who's qualified to make such a statement can look at them first and then say as much.

[fmaderjr]

The issue many of us come across (myself included) is that the mics are NOT MATCHED (a la CoreSound's HEBs) but does this mean that it's better to buy those at 2, 3 or 4x the price?  Likely not.  In my case, I have a 2dB difference between the left and right channels (which I can either fix in post or buy an Ugly preamp to resolve.   

For me & I assume for you, mics that are mismatched by a few dB is really no issue at all. As you say, it is super easy to fix in post or, if I am using a pre with L/R gain knobs like my Littlebox or MixPre, I can match the channels that way.

I had good luck with theater DPA as well, but I got them from a seller with great feedback on DPA sales who bought a lot of them and tested them before reselling. 

I wouldn't buy anything from Core Sound (nor would I have bought DPA 4060's at all if I had to pay $900-$1000 new). Many reports of substandard customer service From Core Sound and I experienced this myself the one time I ordered from him. My $35 cable never arrived and it was like pulling teeth to get him to ship another one. He practically accused my of trying to cheat him.

[adrianf74]

The issue many of us come across (myself included) is that the mics are NOT MATCHED (a la CoreSound's HEBs) but does this mean that it's better to buy those at 2, 3 or 4x the price?  Likely not.  In my case, I have a 2dB difference between the left and right channels (which I can either fix in post or buy an Ugly preamp to resolve.   

For me & I assume for you, mics that are mismatched by a few dB is really no issue at all. As you say, it is super easy to fix in post or, if I am using a pre with L/R gain knobs like my Littlebox or MixPre, I can match the channels that way.

I had good luck with theater DPA as well, but I got them from a seller with great feedback on DPA sales who bought a lot of them and tested them before reselling. 

I wouldn't buy anything from Core Sound (nor would I have bought DPA 4060's at all if I had to pay $900-$1000 new). Many reports of substandard customer service From Core Sound and I experienced this myself the one time I ordered from him. My $35 cable never arrived and it was like pulling teeth to get him to ship another one. He practically accused my of trying to cheat him.

I'm not complaining about 2 or 3 dB.  Any good pair of AKG 480s will be out by 2 to 3 dB so it's more than tolerable.  I'm definitely trying to find a good sized preamp solution now because I'd rather have this sorted when recording but it can be fixed easily.

Exactly - a lot of sellers don't sell duds as they're reputable (and also have great words passed along on these forums via PMs, etc).   I'm not going to knock Len here as I've dealt with him in the past without incident and again, most recently, when I picked up the DPA's.  I purchased some windscreens and clips from him as his prices with shipping were lower than B&H (and he had stock to boot) nevermind the fact that they got here in about a week which is great since I live north of the border.  But as I said, if I had to paid 2-4x as much as I did, I wouldn't have bought the DPAs (and wouldn't have bought them through Core Sound if I bought them new).  After selling my CA-14 omnis and CAFS omnis, I didn't have to pay too much more to cover the cost of the mics, the windscreens, and clips so that's the other reason I made the jump.

[dogmusic]

Thanks for all your input. This forum is great!

I did some more tests, plugging the DPA's into my SP-SPSB-8 battery box and into the mic-in of the D50 (no PIP). The level got better and the noise disappeared from one channel.

I thought perhaps it was my poor soldering skills that were at fault, and I re-did the connectors with RCA plugs, and then into an RCA-to-3.5mm stereo adapter.

Being able to run one mic at a time allowed me to narrow down the problem to one particular mic, and that is where my problem remains.

Below is a sample recording: DPA 4060's > RCA adapter > SP-SPSB-8 batt box > D50 mic-in, no PIP, rec level 4.0.

http://www.box.net/shared/is8omc9390j1ng2sxq5e

The DPA's were put under separate pillows. The bad mic is on the left.

I kept the record level at what I have read here to be unity gain so hopefully no noise was added by the recorder.

I normalized the file in Audacity. Not sure if that was a good idea. It's REALLY LOUD!

So please TURN DOWN YOUR PLAYBACK VOLUME if you decide to listen to it.

Looks like I'll be returning this one, unless someone has another idea about this bad mic.

Thanks again,

Phillip

[Jamos]

A lot of theatres/broadway houses consider body mics to be expendable items.  They get sweat on, covered in makeup, stepped on, etc.

Luckily for folks like us, they often get sold off cheap just to make some money back and are still usable.

Chris Church, you sound pretty full of yourself making comments like the one you did, but I think that's pretty obvious to most.

I hope the OP gets his mics sorted out.

[Church-Audio]

A lot of theatres/broadway houses consider body mics to be expendable items.  They get sweat on, covered in makeup, stepped on, etc.

Luckily for folks like us, they often get sold off cheap just to make some money back and are still usable.

Chris Church, you sound pretty full of yourself making comments like the one you did, but I think that's pretty obvious to most.

I hope the OP gets his mics sorted out.

Full of my self no. Experienced yes. I have been working in live sound for over 23 years now and I dont know anyone that sells a perfectly good working mic for 1/4 of its value. Unless there is an issue. Yeah body mics are expendable sure, but nobody sells off mics that work perfectly. At least nobody I have ever met. Maybe you know people that do, I dont know. I bought a Meyer Sim DPA mic from you if you remember, even then I still took it to DPA and had it tested. I would never have purchased one from a theater because I know better. And my whole point is unless you have a good known mic to compare it too and the gear to test it properly then you don't know if it works like it should. You may know it sounds ok but that does not mean its working like new. I think we can agree on that right?

That is my point. No ego here I don't care what people do a the end of the day people will always buy theater mics. And maybe they are ok maybe not, Its a gamble. I did not mean to ruffle any feathers. I just think people have a false sense of security thinking that these mics will always be perfectly functional often times they are not. Now what some consider functional and what I consider functional might be two different things right?

[it-goes-to-eleven]

Luckily for folks like us, they often get sold off cheap just to make some money back and are still usable.

That's it exactly, I think.   Sell them before they fail, so you get some money out of them.  They probably buy lots at a time.  Maybe they get a discount, especially if they are a non-profit theatre?

I got lucky - my ebay theatre dpa's have been great.   But new or used, those little mics scare me a bit because they can't be repaired if the capsule/cable interface is damaged.   I don't know how much life they have left, or how much of a tug would damage them.  So I always treat them as gently as possible.

I am also hesitant to loan them out, because it'd be a pain if something happened.  How would you handle it?  Finding a replacement pair on ebay would be a major chore.  And the pair you got might not be good.  Etc.

[Gutbucket]

FWIW, I used numerous DPA 4060s over the past 6 years, purchased both new and used, and I've never had a cable failure at the mic or anywhere other than an accidentally yanked off microdot. I've had FETs go bad (not repairable) and solder joints in re-terminated connectors go bad (pretty easily repairable).   On one very early production pair which I bought used (low serial numbers, different cable type), the cable covering hardened, cracked and begain to fall off in large chucks.  The stranded ground/shield copper underneath was heavily patina'd green but the mic worked fine. I recovered it with heatshrink and used it for another 6 months before it died of FET failure. 

My FET failures manifested as a permanently reduced sensitivity of 6+dB, increased noise, and sometimes sensitivity changes while recording (higher SPLs 'woke them up', lower SPL's were more problematic).

[dogmusic]

FWIW, I used numerous DPA 4060s over the past 6 years, purchased both new and used, and I've never had a cable failure at the mic or anywhere other than an accidentally yanked off microdot. I've had FETs go bad (not repairable) and solder joints in re-terminated connectors go bad (pretty easily repairable).   On one very early production pair which I bought used (low serial numbers, different cable type), the cable covering hardened, cracked and begain to fall off in large chucks.  The stranded ground/shield copper underneath was heavily patina'd green but the mic worked fine. I recovered it with heatshrink and used it for another 6 months before it died of FET failure. 

My FET failures manifested as a permanently reduced sensitivity of 6+dB, increased noise, and sometimes sensitivity changes while recording (higher SPLs 'woke them up', lower SPL's were more problematic).

Did you happen to download my second recording sample? I would like to know your opinion if this sounds like an FET failure. (Be sure to keep your playback volume low.)

http://www.box.net/shared/is8omc9390j1ng2sxq5e


Also, have you ever taken off the grids to clean them? I wondered about giving this a shot, but can't seem to budge the grid on this mic.

I think I read one of your posts where you had a set of DPA's that worked with PIP and another that needed more voltage. Did you ever figure out why one did and one didn't?

Thanks,

Phillip

[Gutbucket]

Haven't listened to the sample and unfortuantately I'll not have a chance to for a while (just got home late last night from a fest and I'm working an industry show that starts tomorrow and runs for a week).

The grids just interference fit and pull off.  I used to take them off regularly when I was concerned about the capsule orientation for boundary mounting.  Now I remove them less frequently since internal orientation didn't seem to matter that much.  There is a plastic ring that the metal mesh attaches to as a permanent part of the grid. The plastic ring is what makes an interference fit on the mic body.  Carefully pull that.  Problem is that there isn't much body left on the cable side to hold while you do, and most that is tapered.  If that ring is really stuck, clean off the crud with some isopropyl alcohol (don't let the disolved crud get in the mic through the screen) and swizzle the whole thing in distilled water.  If you get the grid off you can re-swizzle the bare capsule in distilled water as well, but most crud will probably be stuck in the mesh so throuroughly clean the grid when it is off the mic and you needn't worry about messing up the capsule.

I always recommend using a battery box, external preamp, or phantom adapter that provides 5V-10V mic powering.  Even if the mic operates on built-in PIP of less than 5V, it will probably not do so optimally or to specification.  The pair that seemed to work was the very old used pair with low serial numbers and the cable sheath cracking problem.  The only other pair I had at the time was a new pair which did not work with PIP.  I didn't record any music or try any of my other 4060s this way.

If you absolutly need to have a DPA miniature omni that works on typical ~3V PIP, look into the 4063.  It has similar sensitivity to the 4061 is built to operate on lower voltage powering.  The specs suffer a bit for that ability, and I'd think not many outfits use those so don't expect to find those used or get a great deal on them.

[dogmusic]

Haven't listened to the sample and unfortuantately I'll not have a chance to for a while (just got home late last night from a fest and I'm working an industry show that starts tomorrow and runs for a week).

The grids just interference fit and pull off.  I used to take them off regularly when I was concerned about the capsule orientation for boundary mounting.  Now I remove them less frequently since internal orientation didn't seem to matter that much.  There is a plastic ring that the metal mesh attaches to as a permanent part of the grid. The plastic ring is what makes an interference fit on the mic body.  Carefully pull that.  Problem is that there isn't much body left on the cable side to hold while you do, and most that is tapered.  If that ring is really stuck, clean off the crud with some isopropyl alcohol (don't let the disolved crud get in the mic through the screen) and swizzle the whole thing in distilled water.  If you get the grid off you can re-swizzle the bare capsule in distilled water as well, but most crud will probably be stuck in the mesh so throuroughly clean the grid when it is off the mic and you needn't worry about messing up the capsule.

I always recommend using a battery box, external preamp, or phantom adapter that provides 5V-10V mic powering.  Even if the mic operates on built-in PIP of less than 5V, it will probably not do so optimally or to specification.  The pair that seemed to work was the very old used pair with low serial numbers and the cable sheath cracking problem.  The only other pair I had at the time was a new pair which did not work with PIP.  I didn't record any music or try any of my other 4060s this way.

If you absolutly need to have a DPA miniature omni that works on typical ~3V PIP, look into the 4063.  It has similar sensitivity to the 4061 is built to operate on lower voltage powering.  The specs suffer a bit for that ability, and I'd think not many outfits use those so don't expect to find those used or get a great deal on them.

Thanks for all that info. Regarding cleaning the mic, DPA's user manual seems to be against cleaning the element with anything but a dry cotton swab. Is it really okay to dip the entire mic in distilled water?

I don't really need the mics to run on PIP. There are some postings on the web where people have managed to do this, and I had expected mine would as well. It's no big deal to use a battery box now that I know.

[Church-Audio]

One of my best friends is one of the top Live sound engineers for the Toronto Theater community he has been doing sound in theaters for over 40 years and has worked on Broadway ect.. This is what he said when I asked him about theaters selling off good mics.

So you know I am not talking out my ass.

"Bob Shindle

Well, it really depends on the show, and the producer. In the older days when there were actual stars in the shows we would change them out at regular intervals instead of waiting for a burnout. Nowadays you're right though. I don't know of any producers who will incur the expense for no reason. And most shows don't have big names any more. So, yes I would say I agree with you. Once they have sweated out you can still get a bit out of them, but the salt from the sweat has already started to rot the metal"

As far as community theaters are concerned yeah they dump the mics sometimes but very rarely because if they sell a mic they have to put that money back into the theater budget that means next year they get less grant money. Again nobody is going to get rid of a perfectly good mic. Why would they? Why sell a mic for 1/4 its value? If the mic we perfectly working it would be worth at least 50% of its value as mics don't depreciate that much. 

[yousef]

Thanks for all that info. Regarding cleaning the mic, DPA's user manual seems to be against cleaning the element with anything but a dry cotton swab. Is it really okay to dip the entire mic in distilled water?

I think I learned about the distilled water method from a Brian Skalinder post here quoting someone from DPA - I'm sure that searching DPA plus distilled water on these boards will eventually turn it up.

Interesting about what a FET failure might present as - I wonder if that's what's happened to one of mine...

[dogmusic]

Well, strange things do happen. I went out to hang up the kayaks under the screen porch for winter. The bottom of the porch is about 10 feet off the rock that our house is built on, and while balancing on the edge of a picnic table and raising up the end of the kayak with one hand, I pulled up with the other hand on a bungee cord to attach it to a hook under the porch, when suddenly the bungee slipped out of my grasp and the metal part boomeranged back and slammed into my forehead. I almost blacked out.

So while recovering my consciousness, I decided to give those mics another go. Gutbucket had posted regarding DPA FET failures that "higher SPLs 'woke them up' ". So I gave a couple of really loud hand claps in front of that noisy mic. I made a recording and the noise seemed to be lessened. Then I plugged the battery box line-in rather than mic-in as I had been doing, did a test recording with my out-of-tune piano and --- a miracle! The noise seems to be completely gone!

Here is a sample: The 4060's are just sitting on top of the closed lid of my piano, and the chain is DPA 4060's > RCA adapter > SP-SPSB-8 batt box > D50 line-in, rec level 3.0.

http://www.box.net/shared/n8qf3jtz0rmv1dq47xxj

I'm not sure if this is a fluke and that the mic will bounce back into noise (like a bungee cord to the head), but I'll run some longer recordings later and see if it stays quiet.

Thanks once more for everyone's help. And thanks, Gutbucket, for that little nugget of info.

Phillip

[adrianf74]

@Church-Audio: I've never, nor has anyone here, said you were talking out of your ass.  All theatres are different.  I'm doubting your contact and his experience but I've spoken to a musical director at a long-running broadway show and he's told me that they do cycle through their mics to try and avoid major issues.  A lot of the "luck" of the draw isn't really luck but knowing that the seller has tested them prior to putting them up for auction/sale.  Many of us (myself included) have ex-theatre mics and have ZERO issues (other than the expected dB difference between them which is still not really an issue).  In my case, I know who cleaned them up and terminated them and that the person I bought them from treats his stuff very well.   In the case of dogmusic, he might have gotten a "dog" mic (it does happen).

@Gutbucket: Thanks for the info on the FET failure and what that looks like.  I know I don't suffer from this (yet) - touch wood - but will keep my ears (and eyes) open just in case.

it-goes-to-eleven: I doubt there's any "bulk purchase" discount available on them when the best price I'm seeing is around US$450-470.  As far as the "mileage left" goes, I would just say to treat your current mics as well as you treat any other gear.  I try not to pull on the cables or be rough with the capsules -- I always throw them in an earplug case (the capules) when I'm done recording and then place them back in the DPA box when I get home and they're not in use.   The good news is that if you ever had a dud pair, the "replacement" cost from DPA is ~$300 per mic for brand new ones.   Figuring that you paid around ~$100 per mic, you still paid less for them if you ever had to replace them outright (or you could roll the dice and try FleaBay again but that can be hit or miss as has been shown).

dogmusic: With the 406x mics, I'd always want to use a battery box at a minimum or a preamp if you had access to one.   Makes controlling them a lot easier.  I'm glad that it looks like you got them to wake up.   That's an old trick that also helps (the hand clapping thing).  Let us know if the noise comes back.

[dogmusic]

In the case of dogmusic, he might have gotten a "dog" mic (it does happen).

That's an old trick that also helps (the hand clapping thing).

Well, I guess you can teach an old "dog" old tricks. 

[John Willett]

Personally I would never buy ex-theatre tie mics. as they are very likely to be sweated-out.

This tends to be the main problem with mics. used in the theatre.  Also the possibility of damage due to make-up and/or hair-spray.

[Church-Audio]

Well, strange things do happen. I went out to hang up the kayaks under the screen porch for winter. The bottom of the porch is about 10 feet off the rock that our house is built on, and while balancing on the edge of a picnic table and raising up the end of the kayak with one hand, I pulled up with the other hand on a bungee cord to attach it to a hook under the porch, when suddenly the bungee slipped out of my grasp and the metal part boomeranged back and slammed into my forehead. I almost blacked out.

So while recovering my consciousness, I decided to give those mics another go. Gutbucket had posted regarding DPA FET failures that "higher SPLs 'woke them up' ". So I gave a couple of really loud hand claps in front of that noisy mic. I made a recording and the noise seemed to be lessened. Then I plugged the battery box line-in rather than mic-in as I had been doing, did a test recording with my out-of-tune piano and --- a miracle! The noise seems to be completely gone!

Here is a sample: The 4060's are just sitting on top of the closed lid of my piano, and the chain is DPA 4060's > RCA adapter > SP-SPSB-8 batt box > D50 line-in, rec level 3.0.

http://www.box.net/shared/n8qf3jtz0rmv1dq47xxj

I'm not sure if this is a fluke and that the mic will bounce back into noise (like a bungee cord to the head), but I'll run some longer recordings later and see if it stays quiet.

Thanks once more for everyone's help. And thanks, Gutbucket, for that little nugget of info.

Phillip

I have done the same dam thing but not with a Kayak. It hurts me to just think about it. Hope your head feels better. My theory behind the failure of the fets is that sweat corrodes the metal leads of the fet and works its way inside the fet and partially shorts it out. Thus any mic that has been sweated out is on borrowed time. Like others have mentioned a tell tail sign of a mic that has been exposed to sweat will be the sham rock green shield wire when you strip it to put the connector on.

[Gutbucket]

John posted whil I was typing with a similar sentiment on sweat and hair spray.. here's the post-

Check your cables and solder connections.  That's the usual culprit and soldering those hair thin signal conductors is not super easy.  A compromized joint can also 'awaken' if enough juice flows to bridge the resistance of a 'sometimes but not always' intermitant connection or a cold solder joint.  I'd suspect that before a bad FET.  DPA can check and confim a bad FET, but will need to cut off any custom termination in their troubleshooting to do so.

Chris Church knows his stuff.  He knows mics from both the technical and the practical 'real world' side.  I think he's right on with his comments.  It's contaminants in sweat (especially the salt) and arisol sprays that concern me the most and which I believe are most likely to kill theater, film or TV sourced mics at some point.  The makup, paint, tape goo and outside uglyness don't make it past the metal mesh grid for the most part, which is easily removed, cleaned or replaced.  It's the mostly unseen moisture-born contaminants that are the problem. That's what's up with the recommendation for nothing but distilled water to clean the naked capsule- distillation removes all minerals and other residual contaminants.  I've had several people at DPA in the US confirm that the distilled water swizzle is OK, but I've never felt the need to do that myself yet. I had one of a pair stop working when soaked with rain at a fest, but continued working and was fine once it dried out later that day.  Probably would have been wise to swizzle those afterwards but they are still working correctly 4 years later, then again it was soaked by clean rain water directly from the sky.  If it was sweat saturated I would have dunked it for sure.

I have bought a batch of B3s and more recently 4061s off ebay.  The seller was reputable, & claims to test for operation beforehand.  They came clean. The six B3s all worked fine.  I haven't had time to check the batch of 4061s yet, but bought from the same vendor as the B3s and I feel confident they'll be OK.  Don't know where he gets them.  I was prepared for problems or limited longevity. Caveat emptor.

[it-goes-to-eleven]

Wait a minute.  Are you saying that the bungie hit your head, and knocked some sense into you?  And then you took it out on the microphone, and after screaming into it (*), it started working better?

That's amazing!

Or maybe the knock on the head is causing audio hallucinations?

EIther way, it works!  It only matters how it sounds to you

You are very lucky the damn bungie didn't rip your eye out!

* - I know you said claps but screams make a better story.

[Gutbucket]

You are very lucky the damn bungie didn't rip your eye out!

I've done it. The thought of that hook potentially catching an eye freaked me out way more than the big knot on my forehead.  Yikes.

[illconditioned]

Dudes, if anyone has a broken DPA 406x mic, I'd like to dissect it.

Go on, contribute your broken mic to science!

I'm particularly interested in the circuit behind it.  My guess (from limited DPA disclosure) is there is a FET inside the capsule, and a standard BJT just outside it.

  Richard

[Church-Audio]

Dudes, if anyone has a broken DPA 406x mic, I'd like to dissect it.

Go on, contribute your broken mic to science!

I'm particularly interested in the circuit behind it.  My guess (from limited DPA disclosure) is there is a FET inside the capsule, and a standard BJT just outside it.

  Richard

That is correct.

No need to take it apart The fets are part of the way that mic sounds but the major part is that diaphragm and mic housing. I have recabled a few of them its not fun and its a 50 / 50 chance they wont make it through the operation It involves a microscope and a dental pick. And some heat to break down the epoxy.

[dogmusic]

Wait a minute.  Are you saying that the bungie hit your head, and knocked some sense into you?  And then you took it out on the microphone, and after screaming into it (*), it started working better?

That's amazing!

Or maybe the knock on the head is causing audio hallucinations?

EIther way, it works!  It only matters how it sounds to you

You are very lucky the damn bungie didn't rip your eye out!

* - I know you said claps but screams make a better story.

That's right! First I knocked some sense into myself, and then into the microphone!

Audio hallucination: that's why I posted the sample. Maybe someone will tell me I'm not dreaming....

You're right I'm lucky -- narrow escapes like that make my teeth hurt.

[dogmusic]

Hope your head feels better.

Like others have mentioned a tell tail sign of a mic that has been exposed to sweat will be the sham rock green shield wire when you strip it to put the connector on.

Thanks for the well wishes. I expect to have a bump like a rhino horn in the morning.

I don't know if this means that my mics were not exposed to sweat, but the shielding was pure silver when I stripped it.

[MIQ]

Hi dogmusic,

I took a close listen to the recording you made of the piano.  To me, it seems like there is a little distortion on the attacks of chords/notes but only in the left ear.  I listened with headphones a couple of times to make sure I wasn't imagining it.  Not sure if it is the left mic or something else in the signal chain but I'm certain there is something wrong still.    It has a kind of tamborine/snare quality and is more pronounced on low notes.  Maybe someone else can take a close listen and let us know if they hear it too. 

Hope your head feels better. 

-MIQ

[dogmusic]

Hi dogmusic,

I took a close listen to the recording you made of the piano.  To me, it seems like there is a little distortion on the attacks of chords/notes but only in the left ear.  I listened with headphones a couple of times to make sure I wasn't imagining it.  Not sure if it is the left mic or something else in the signal chain but I'm certain there is something wrong still.    It has a kind of tamborine/snare quality and is more pronounced on low notes.  Maybe someone else can take a close listen and let us know if they hear it too. 

Hope your head feels better. 

-MIQ

Hi MIQ,

Thank you for your close listening. I am afraid you are right. There is still a problem with the one mic, which was plugged into the left channel.

When I did the second of my three tests [DPA 4060's > RCA adapter > SP-SPSB-8 batt box > D50 mic-in, no PIP, rec level 4.0, mics under the pillow], I had set the mic/line switch on the D50 to "mic".

(Despite the fact that there are separate inputs on the D50 for "mic" and "line", there is also a switch on the side which you have to change according to your input.)

When I did the last test (recording the piano), I plugged the battery box into the line-in instead of mic-in, but I forgot to change the switch from "mic" to "line". The excessive level of hiss/noise in the left channel mic became much less apparent in that setting --- not sure why the D50 operates that way.

But the mic is indeed not working well. Running another test going mic-in revealed the noise to still be there.

I'm in touch with the ebay merchant and I'll let you all know how this turns out.

Again, thanks MIQ and everyone else for your help.

And thanks for your well-wishes too, MIQ.  I wish my knock on the head had turned out to be good luck for the mic. 

[dogmusic]

After I contacted the ebay vendor regarding the one noisy mic, he immediately sent me a replacement.

I received it yesterday and connected it up this morning. Sounds good. No extra noise or hiss like the bad one.

I guess it was just the luck of the draw, or perhaps it got damaged during the shipping.

I highly recommend this ebay vendor in Las Vegas. He acted super-fast and friendly.

Thanks again for everyone's input and suggestions and support on this. This forum is a big help.

[newplanet7]

After I contacted the ebay vendor regarding the one noisy mic, he immediately sent me a replacement.
I received it yesterday and connected it up this morning. Sounds good. No extra noise or hiss like the bad one.
I highly recommend this ebay vendor in Las Vegas. He acted super-fast and friendly.

Awesome!
I absolutely love hearing things like this.
Almost restores some sort of faith in humanity.

[BusDriver]

I'm late to reading this thread .. it is an ear-opener .... and I will attest to the power of bungee to forehead - it does 'wake up' and 'knock sense' into one's self. About a year and half ago I took a bungee clip hit to the forehead about an inch above the left eye. Talk about dazed and confused, spurting blood on the car on the side of the road .. YOW ... still have nerves not fully reconnected - push forehead feel it on top of knoggin - but still have sight in both eyes. DON'T MESS WITH THE BUNGEE !!