Hey everyone. I recently plugged my Sennheiser G2 lav into my Tascam DR-100 with the phantom power accidentally (or foolishly) turned on. Immediately it peaked the levels and was just an ear piercing noise. I quickly removed it and realized what I did. I've heard that this can fry the mic or just cause interference. But since then both the Tascam and the Lav only get peaked noise signals even when plugged in to other devices. The Tascam is doing this with all input signals too, not just the XLR. So while I could understand why the mic might be fried (would this level peaking even be a symptom of that?) it seems strange that it would have destroyed the Tascam too. Would/could this be an unbalanced thing? Any help would be very appreciated!
Did I fry my mic and recorder?
- Thread starter yojroz
- Start date
paulears
Veteran
I assume the lav is fitted with a 3.5mm plug as usual? Did you use and adaptor of some sort to get the mic into the XLR? I'm a bit confused as to what exactly you did? The only other scenario is you plugged a receiver into the XLR? The Sennheiser receiver is unbalanced, so the usual cable shorts one of the audio lines to ground. You say that since doing it the lav(receiver?) AND the Tascam only get peaked noise signals (distortion?) There is a faint possibility that the phantom FROM the Tascam could have damaged the receiver, but my experience is that the Sennheisers are pretty proof against output short circuits, so it seems a bit unlikely they'd have a good design against shorts, but be prone to phantom - which is a pretty common mistake. As the receiver only presents 'half a short' to the Tascam, again, my experience is that damage is unlikely - but you have distortion on both? Can you explain a little more exactly what you did and how the fault was caused - and what kind of symptoms you now have.
My lav has the 3.5mm plug from receiver as well as an XLR from receiver. I have never used these two items together. I always use a boom (needing phantom) with the recorder and plug the lav receiver directly into a camera that takes XLR. But in this case I tried the two together. Immediately when I plugged the XLR in, both my recorder and the receiver seemed to "short" (don't think that's the right word) and both level meters peaked. If I even turn on the lav receiver while plugged in to nothing it's levels are peaking. When the Tascam is on, it is peaking as well, whether it's set to line in, XLR, or the two onboard mics. It's all just peaked noise. Doesn't seem to me like I fried the mic as much as I set off some sort of short that has both of them "confused". I'm hoping there is a way to reset them or something. They both seem to function...they are just peaking.
Rick R
Veteran
The Tascam recorder should be tested with properly balanced mics, both dynamic and Phantom Powered with the record level set to "manual".
If this checks about OK, the recorder is likely OK.
An unbalanced lav mic (like the Sennheiser G series ME2/4) would not work at all with the Tascam's XLR or 1/4".
It's certainly possible damage was done to the mic though. One consolation, even if you did fry the mic, the G2/3 ME2 ain't that good anyway.
What do you mean by "peaked noise signals"?
Thanks for the help. It doesn't seem like the mic is fried since both it and the Tascam are having the same symptoms. When I turn either one of them on (the Tascam or the G2 receiver) immediately the audio levels are peaking. If I listen it is a high pitched noise or squeal that is very loud (almost like the tone that accompanies bars). On the G2, this is happening on just the receiver when it's not even plugged in to anything else. On the Tascam, it is happening with nothing being input and on any input setting...Line in, XLR, or either of the two on board mics. It's almost as if something shorted when I plugged the mic in to it.
Richard Crowley
Veteran
It surely sounds like you have fried one or more pieces of your kit.
It is really terribly confusing when you say things like:
Do you mean you plugged the G2 RECEIVER into your Tascam DR-100, or do you mean that you plugged the Sennheiser lav mic (the one that normally plugs into the body-pack transmitter) into your Tascam DR-100 (and HOW exactly??)?
And we really don't know what this means either....
What does "used these together" mean? How would you even do that? You can connect only one at a time to the receiver, can you not?
It is really terribly confusing when you say things like:
Do you mean you plugged the G2 RECEIVER into your Tascam DR-100, or do you mean that you plugged the Sennheiser lav mic (the one that normally plugs into the body-pack transmitter) into your Tascam DR-100 (and HOW exactly??)?
And we really don't know what this means either....
What does "used these together" mean? How would you even do that? You can connect only one at a time to the receiver, can you not?
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Thanks for the input and for the clarifying questions. It's hard for me to verbalize what the problem is. To answer your questions...
-I ran the receiver of the G2 into the Tascam via XLR. When I mentioned the 3.5mm, I was answering the question posted that yes, it does have that as an option but I didn't use that. I used the XLR from G2 receiver into the Tascam.
-When I said "I have never used these two items together" I meant the Tascam DR-100 and the Sennheiser G2. As I went on to explain, I usually use the Sennheiser G2 receiver directly into my camera's XLR. And I usually use the Tascam DR-100 with a boom mic that needs phantom power.
In my problematic case, I ran the G2 receiver into the Tascam's XLR input with phantom power on. Immediately the audio levels on both the Tascam and the G2 receiver went to the max with a solid high pitched tone. Now even when the two are independent (no input to the Tascam, and the G2 receiver not run to anything) they still have this audio problem. As I said, it doesn't seem like it's just a situation of overpowering the G2 because it and the Tascam are having the same issues. Seems like something shorted out. I'm hoping there is something I can do to fix the problem because the two devices are unusable right now. Hope this clarifies.
-I ran the receiver of the G2 into the Tascam via XLR. When I mentioned the 3.5mm, I was answering the question posted that yes, it does have that as an option but I didn't use that. I used the XLR from G2 receiver into the Tascam.
-When I said "I have never used these two items together" I meant the Tascam DR-100 and the Sennheiser G2. As I went on to explain, I usually use the Sennheiser G2 receiver directly into my camera's XLR. And I usually use the Tascam DR-100 with a boom mic that needs phantom power.
In my problematic case, I ran the G2 receiver into the Tascam's XLR input with phantom power on. Immediately the audio levels on both the Tascam and the G2 receiver went to the max with a solid high pitched tone. Now even when the two are independent (no input to the Tascam, and the G2 receiver not run to anything) they still have this audio problem. As I said, it doesn't seem like it's just a situation of overpowering the G2 because it and the Tascam are having the same issues. Seems like something shorted out. I'm hoping there is something I can do to fix the problem because the two devices are unusable right now. Hope this clarifies.
MattinSTL
Sound Modulator
All you can do is trouble shoot each piece... which it sounds like you've already done.
If you haven't yet, you should be able to safely try each bit in it's normal configuration and see if you get anything... Plug a mic into the recorder (agree with the other post, try a dynamic mic w/o the phantom switched on... then try a condenser with the phantom)... then try the G2 receiver plugged into a camera or in a situation where it would normally work.
If nothing is working, then yes, you fried them.
Sending 48v into a receiver that wouldn't normally have anything going into it... probably not good. I'd be surprised if Sennheiser didn't have something in place for this... like maybe a fuse or something in there, even if it's something you can't get to, but a repair shop can. Then I'm guessing you may have had the line-out turned up on the receiver... like +12db or something... which the Tascam wouldn't know what to do with either... basically even though these things can plug together... each is way beyond max'ed on the expected levels.
All you can do is try each thing in a situation where it previously worked... and this is at your own risk of course. Otherwise send them in to a shop.
If you haven't yet, you should be able to safely try each bit in it's normal configuration and see if you get anything... Plug a mic into the recorder (agree with the other post, try a dynamic mic w/o the phantom switched on... then try a condenser with the phantom)... then try the G2 receiver plugged into a camera or in a situation where it would normally work.
If nothing is working, then yes, you fried them.
Sending 48v into a receiver that wouldn't normally have anything going into it... probably not good. I'd be surprised if Sennheiser didn't have something in place for this... like maybe a fuse or something in there, even if it's something you can't get to, but a repair shop can. Then I'm guessing you may have had the line-out turned up on the receiver... like +12db or something... which the Tascam wouldn't know what to do with either... basically even though these things can plug together... each is way beyond max'ed on the expected levels.
All you can do is try each thing in a situation where it previously worked... and this is at your own risk of course. Otherwise send them in to a shop.
Hi One quick test, but low likelihood. Maybe you have some very strong RFI (radio frequency interference) nearby. Take one or both to another location and see what happens. Just a thought since it is so easy to do. And when you do this leave your cell phone behind. I wish you good luck for an easy fix.
paulears
Veteran
I'm surprised the result of the connection was an identical fault in both! In the XLR cable from the receiver, as one of the audio lines is shorted to earth, then the 48V, applied via two resistors is a potential divider and current limited 24V would have gone up the spout, so to speak. I can't see a logical reason for the Tascam to suffer from this, because it would have been the cause of the possible fault condition - so something else has happened. My own accidental faults of this kind have never destroyed anything - for example, sticking a cable between a mixer input with phantom accidentally turned on, into a mixer output produced a nasty whine plus ful scale meter readings on the output of the mixer - so what came back up the 'out' certainly annoyed it but with no damage, mainly I suspect due to capacitor isolation on the output. Shorting inputs, or even paralleling phantom powered inputs, also always considered a bad move, never caused any faults. Of course, some device output stages that are less well designed could be damaged, but decent kit is usually designed to be resilient.
So your 'damaged' receiver, when plugged into the usual mic socket of your camera now produces a continual tone of full scale meter display? Your Tascam, when nothing is plugged into it also generates a full scale level and the same noise?
Can you confirm these two facts please, then we can progress.
So your 'damaged' receiver, when plugged into the usual mic socket of your camera now produces a continual tone of full scale meter display? Your Tascam, when nothing is plugged into it also generates a full scale level and the same noise?
Can you confirm these two facts please, then we can progress.
Thank you everyone for the immense help. Paulears, yes everything you said seems to make sense and to be the case. I too don't understand how the Tascam could have been damaged when it was the one sending out the power. To answer your questions, yes, when the receiver of the G2 is plugged in via XLR to my camera (as I usually use it), the meters are fully peaked. Even unplugged from the camera and just on they are peaking. And yes, the Tascam is the same, fully peaked meter when on and not plugged in to anything, and despite which of the 4 input settings it's switched to...line in, XLR in, or the onboard uni or omni mics.
As to Blit's suggestion, the location where this went down and my home where I am troubleshooting them are two different locations, so it doesn't seem like locational interference.
Noiz2
Sound Ninja
Shorting out the phantom power supply can damage the recorder. Theoretically there may be a way to short the power and feed it to the preamps (shouldn't be possible but?) and that could damage the preamps.
As to the Wireless, are you sure that the meter peaking out is the AF and not the RF signal? With the transmitter close the RF should be "peaked" out, just means you have a good connection.
As to the Wireless, are you sure that the meter peaking out is the AF and not the RF signal? With the transmitter close the RF should be "peaked" out, just means you have a good connection.
paulears
Veteran
There's something wrong here, very wrong. On the Tascam, have you got the peaking with no plug in the socket on both channels or just one? On the receiver, does the audio peak light come on when you plug it in, or is it there all the time? It makes me wonder if the camera has it's phantom turned on too, as the Tascam had when the problem started. I expect you have checked but the first thing I'd do is make sure the camera hasn't accidentally got phantom turned on. If the receiver has the AF peak light on without being attached to the camera, the next thing to check is that the squelch is actually closed. If it's open, then the output will be white noise, and cause the light to come on - so check the squelch setting.
Is there any chance we could hear the sound the tascam is generating - I presume hitting record does actually record the noise - and if possible the same thing recorded by the camera?
This is a very strange one!
Is there any chance we could hear the sound the tascam is generating - I presume hitting record does actually record the noise - and if possible the same thing recorded by the camera?
This is a very strange one!
Sorry for the delay. Easter, then a sick family. Here is a link to the sound that is recorded...again it is the same no matter what input setting I have it set to and with no mic attached. Also, in this clip using the onboard mic I tried to talk as well and it was not picked up. So this noise is canceling out the mic from working too. And the receiver of the G2 is sending the exact same sound when it is attached to anything. As always any thoughts are appreciated.
http://yourlisten.com/channel/content/16969166/Hum_sample?&_suid=136501844947005762714329175651
http://yourlisten.com/channel/content/16969166/Hum_sample?&_suid=136501844947005762714329175651
Yojroz,
You'll have to continue with your tests to isolate where the current issues are. I can explain more about how damage can occur from phantom fault conditions.
It's less likely (but still possible) that the wireless receiver is damaged. It will have a cap as a DC block on the output. They likely anticipate this fault condition, and have the voltage rating for the cap well over 50V.
2 bad things can happen to your recorder. First, when you short phantom, the switching power supply generating the phantom voltage will work extra hard to keep generating the 48V. Eventually, it can overheat and fry. Second, the large caps at the recorder inputs already charged with 48V, will be forced to rapidly discharge when a short is presented at the input. The backside of the cap needs to pull the current from somewhere, and it can find a path through the preamp, frying that. The AES had a great paper about this called "The Phantom Power Menace":
http://www.thatcorp.com/datashts/AES7909_48V_Phantom_Menace_Returns.pdf
Although, depending on the wireless reciever output stage, it may suffer from the same issue, but in reverse, where the charging of the output cap needs to pull current on the back side, and could damage the output driver.
So, the upshot is, you NEVER want to apply phantom power to anything other than a condenser mic which requires it ...
Robert from juicedLink
You'll have to continue with your tests to isolate where the current issues are. I can explain more about how damage can occur from phantom fault conditions.
It's less likely (but still possible) that the wireless receiver is damaged. It will have a cap as a DC block on the output. They likely anticipate this fault condition, and have the voltage rating for the cap well over 50V.
2 bad things can happen to your recorder. First, when you short phantom, the switching power supply generating the phantom voltage will work extra hard to keep generating the 48V. Eventually, it can overheat and fry. Second, the large caps at the recorder inputs already charged with 48V, will be forced to rapidly discharge when a short is presented at the input. The backside of the cap needs to pull the current from somewhere, and it can find a path through the preamp, frying that. The AES had a great paper about this called "The Phantom Power Menace":
http://www.thatcorp.com/datashts/AES7909_48V_Phantom_Menace_Returns.pdf
Although, depending on the wireless reciever output stage, it may suffer from the same issue, but in reverse, where the charging of the output cap needs to pull current on the back side, and could damage the output driver.
So, the upshot is, you NEVER want to apply phantom power to anything other than a condenser mic which requires it ...
Robert from juicedLink