Low Volume with Condenser Mic

M

mariosapm

New member
I have a Behringer MIC100 connected with a (approx 10m) XLR cable to a Behringer B2 condenser mic.

The cable and preamp combination works perfectly with my Shure Beta, though this is a dynamic.

Now here are some observations:

The volume is very low but hearable. When I switch patterns (since this is an omnidirectional mic) I have a sudden increase in volume and for half a second it sounds at normal levels then drops again. This only when I use the little pattern change switch.

Any ideas?
 
The pattern changing noise/gain change happens with many mics when you swap patterns, it takes a second or two for the phantom power to power up the preamp in the mic - and most have capacitors that need to charge before the gain becomes stable.

If you are getting a lower output than your dynamic mic, I'd double check that the cable you are using to the preamp is wired correctly - as in pin 1 to 1, 2 to 2, 3 to 3, and has not got a partial or complete short on 2 or 3. With the preamp connected to a dynamic mic, swapping it for the condenser should not bring about a drop in level, but normally a slight increase. The mic won't work without phantom, so a cable fault is the likely culprit - swap it for another and see what happens. Many phantom power supplies can only just supply the current demanded by the microphones, so the charge up time is quite normal. Some mics that have lower current demands power up very quickly. Large diaphragm mics take longer because of their design. It's also common to get a nasty thump when changing patterns, so always best to mute the channel before prodding the switch.
 
Steenamaroo said:
Hey,
Have you got the power supply connected and the old phantom-power-a-rino turned on?
Click to expand...

sure. I have tested it yesterday with a dynamic mic (with phantom power switch off obviously).

could it be that the cable is too long or too crappy to give phantom power to the mic?
 
mariosapm said:
could it be that the cable is too long or too crappy to give phantom power to the mic?
Click to expand...

Negative. There's an extremely slim chance that the cable isn't balanced, but I doubt that. Throwing it out there!
Is the mic known to work? Have you tested it elsewhere?

Do you have a voltmeter or another mic to guarantee that phantom power is working and being provided?
 
mariosapm said:
sure. I have tested it yesterday with a dynamic mic (with phantom power switch off obviously).

could it be that the cable is too long or too crappy to give phantom power to the mic?
Click to expand...
It is possible that the cable has a short in either pin 2 or 3. A dynamic mic will still work even if you are missing either 2 or 3. But phantom power won't pass, so the condenser mic won't work.

I would try the mic on with a different cable, if it still doesn't work, try the mic with a friend's mixer/preamp/interface.
 
mariosapm said:
sure. I have tested it yesterday with a dynamic mic (with phantom power switch off obviously).

could it be that the cable is too long or too crappy to give phantom power to the mic?
Click to expand...

You can operate a dynamic on phantom power...............doesn't hurt (or do) anything.
 
Farview said:
That is your problem. Get a new cable and everything will work right.
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Alright! I opened the cable end and found out the ground had some strands of copper exceeding to pin 2 and it was shorting it. So I tucked those out of there and re-closed it. I haven't tried it yet with a mic but now I have no short so it will work I guess.
 
mariosapm said:
Alright! I opened the cable end and found out the ground had some strands of copper exceeding to pin 2 and it was shorting it. So I tucked those out of there and re-closed it. I haven't tried it yet with a mic but now I have no short so it will work I guess.
Click to expand...

Hopefully that'll sort it out.
I'd tin those strands or, at least, cut them to prevent it happening again.

If this doesn't work out I'd get a volt meter and test that phantom power. The short circuit could have damaged the 48v supply.
 
Steenamaroo said:
Hopefully that'll sort it out.
I'd tin those strands or, at least, cut them to prevent it happening again.

If this doesn't work out I'd get a volt meter and test that phantom power. The short circuit could have damaged the 48v supply.
Click to expand...


I think something has happened to my mic pre-amp. It's pretty noisy, even with the dynamic mic now. And the volume is not so loud with both mics. Also I notice that voltage is 43 volts when not connected to the mic, while when connected to the mic it drops down to 29 volts. And I can't manage the noise. You think my preamp is shot? I know that some voltage drop is normal but I am not sure if it should be so much.

Thing is that now I get lots of noise that I did not get before, be that a dynamic mic, condenser mic with phantom power, or guitar connected to the Behringer Mic100 and then to the line in of the sound card

To clear things up, I am talking about quite a lot of noise, not just a bit of hiss here and there.
 
The noise increases with both the input and output control of the MIC100. The noise level and crackle seems pretty high no matter what the settings. I usually set the levels from Cubase input mixer and from my hardware and just record.
 
Could be the tube.
Have you tried a new mic cable. That is the first thing I would try before anything and you can always use it down the road. The cable could be the culprit still. Especially if this noise was brought on after you fiddled with it. Like 10 bucks.
Get a cable and on another note. If you buy your mic cables at the Source or Radio Shack. Well...I have had some pretty crappy experiences with their cables. Mind that was when I started out years ago. Now I buy quality cables.

Lou
 
Of course!
... I assumed that you have heard digital overs before. If its a loud oscillating sound you may have your gain too high making overs in your DAW. The second that the input hits over Zero on your track input meter. Digital recording is not forgiving. Not like analogue or tape. You record at -12db to leave room for peaks in your source. Unless you use a compressor or limiter before the computer. Which I do especially on vocals and bass.
Arcaxis has good point.
 
mariosapm said:
I think something has happened to my mic pre-amp. It's pretty noisy, even with the dynamic mic now. And the volume is not so loud with both mics. Also I notice that voltage is 43 volts when not connected to the mic, while when connected to the mic it drops down to 29 volts. And I can't manage the noise. You think my preamp is shot? I know that some voltage drop is normal but I am not sure if it should be so much.

Thing is that now I get lots of noise that I did not get before, be that a dynamic mic, condenser mic with phantom power, or guitar connected to the Behringer Mic100 and then to the line in of the sound card

To clear things up, I am talking about quite a lot of noise, not just a bit of hiss here and there.
Click to expand...

A few facts (again!) about spook juice.

43V is just outside the tolerance of +or - 4V but I doubt another volt low will matter.

29V with mic connected indicates a current of 4.4mA and that is pretty standard.

You cannot damage a pre amp's phantom power supply by shorts. Worse case dissipation in each of the 6k8 feed resistors would be ~340mW so unless the unit had really wee, surface mount chip resistors it should survive a short indefinitely.

Dave.
 
ecc83 said:
A few facts (again!) about spook juice.

43V is just outside the tolerance of +or - 4V but I doubt another volt low will matter.

29V with mic connected indicates a current of 4.4mA and that is pretty standard.

You cannot damage a pre amp's phantom power supply by shorts. Worse case dissipation in each of the 6k8 feed resistors would be ~340mW so unless the unit had really wee, surface mount chip resistors it should survive a short indefinitely.

Dave.
Click to expand...


Well, then it crapped out for no reason I guess. It worked before the cable incident happened. I now have to repair this.
 
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