Phantom power reduces signal on non-condenser... is this normal?

[Obstacle1]

Hey,

I was trying to record with a 57 for the guitar and a condenser for my vocals, i noticed that when i turned on the phantom power the signal of the 57 became weaker - so much so that i had to blast up the gain - the noise was horrible! is this usual?

Thanks

 

[dgatwood]

Hey,

I was trying to record with a 57 for the guitar and a condenser for my vocals, i noticed that when i turned on the phantom power the signal of the 57 became weaker - so much so that i had to blast up the gain - the noise was horrible! is this usual?

No, that's not normal. Phantom power should have no detectable effect on dynamics. Check the cable and see if one of the signals is shorted to ground. Failing that, are you sure that's not a 10dB pad button?

 

[soundchaser59]

not normal at all....sumpin is wrong....most likely the cable.

 

[Obstacle1]

When u say cable do u mean the cable as in the XLR or the actual internal cable of the mic?

Failing that, are you sure that's not a 10dB pad button?

No, its definately +48v phantom power.

 

[phaqu]

Im guessing that your using the phantom power on a board or a pre that fires up all ( or at least 8) of the inputs at once. Change cables (The xlr cable that connects the mic to the pre) and see what happens. If it still does it, move it to a different input. Then try a different mic. Do what you can in the proses of elimination.

 

[Tim Gillett]

As well, never switch the phantom power on or off with the mixer/amp switched on. It can cause a massive transient which could damage your gear as well as your ears.

The loss of apparent gain COULD be temporary deafness after the transient hit your eardrums...

Tim

 

[mixsit]

As well, never switch the phantom power on or off with the mixer/amp switched on. It can cause a massive transient which could damage your gear as well as your ears.

This seems odd to me. I would think; Let the mixer (pre or whatever) power up and time to stabilize first.
How about just keeping things turned down? -for that mater a good bet even before the mixer is booted up too.

 

[Daniel Reichman]

What mixer are you using? I've seen this happen on cheap Behringer and Yamaha mixers.

 

[SRR]

I had this happen once to a Shure 565 running off a Ramsa WRS852 (big live sound board). It was for a graduation ceremony at my college that I went to, where the ceremony was moved from outside at the foot ball field to inside to the main auditorium because of rain right before it started, I was in charge of setting up everything in the auditorium as the rest of the people were scrambling to set up video and sound for over flow in the basketball gym. A very hectic day to say the least, I got everything plugged in and raring to go on stage, and one of the other students hit the phantom for the two mics that I had set up at the podiums. Well as we all know 565's are dynamics, and for the love of Pete one of them failed to produce any sound at the start of the ceremony, so I was waving from the mix position to the President of the college to use the second podium, cause when I quickly scanned the channel everything was assigned correctly, but it was dead, only 1/5 thru the ceremony did I see the phantom power was on for that channel, turned it off and wah-la it worked again. We never did track down why it didn't work.

I could be wrong, but I think someone like Shure (I know Naiant had one), makes a phantom power blocker, if switching out mics (if you have more of the same mic) or switching out cables doesn't do it, search out a phantom power blocker.

Good luck!

 

[Obstacle1]

What mixer are you using? I've seen this happen on cheap Behringer and Yamaha mixers.

The behringer UB1202 - the cable swapping proved to solve nothing so I'm guessing it's my cheap ass mixer - Does anyone know if something like the PV-10 would have this problem? As though the Yamaha MG's are out the question if they have the same problem, the PV-10 its the only other mixer within my price range.

I'm going to look into a phatom power blocker too - thanks alot guys.

Lee

 

[MCI2424]

Hey,

I was trying to record with a 57 for the guitar and a condenser for my vocals, i noticed that when i turned on the phantom power the signal of the 57 became weaker - so much so that i had to blast up the gain - the noise was horrible! is this usual?

Thanks

Check Your cable.

 

[mshilarious]

I could be wrong, but I think someone like Shure (I know Naiant had one), makes a phantom power blocker

I don't anymore, but I published a schematic in my last couple of posts. However, for a dynamic other than a ribbon, two capacitors will do the job fine, but they shouldn't be necessary if the cable and mic are properly wired, and the mic has a transformer.

Transformerless dynamics often don't like phantom power very much. Of course the 57 is not a transformerless mic, unless this is one of those modded 57s. I don't know about the 565.

 

[mixsit]

Have you tried to measure to see that it's actually sending equal +/-48 (or so) volts dc? -Does it power a condensor mic?

 

[dgatwood]

The behringer UB1202 - the cable swapping proved to solve nothing so I'm guessing it's my cheap ass mixer - Does anyone know if something like the PV-10 would have this problem? As though the Yamaha MG's are out the question if they have the same problem, the PV-10 its the only other mixer within my price range.

The PV8 definitely does not, so I'm pretty sure the 10 doesn't, either. I can't imagine how any mixer could have that sort of problem unless the designers were incompetent....

 

[dgatwood]

Transformerless dynamics often don't like phantom power very much. Of course the 57 is not a transformerless mic, unless this is one of those modded 57s. I don't know about the 565.

Just tried it. The 565 doesn't mind phantom. If you have a problem with phantom and such a mic, either your 565 is broken or the problem is elsewhere.

 

[mshilarious]

Just tried it. The 565 doesn't mind phantom. If you have a problem with phantom and such a mic, either your 565 is broken or the problem is elsewhere.

I had a look at the 565 datasheet; I don't know how many versions there were, but it looks like the early ones used a dual-impedance 4 pin Amphenol connector, so there is plenty of room for Amphenol-XLR cable shenanigans . . .

 

[dgatwood]

I had a look at the 565 datasheet; I don't know how many versions there were, but it looks like the early ones used a dual-impedance 4 pin Amphenol connector, so there is plenty of room for Amphenol-XLR cable shenanigans . . .

I suspect there were several 565s. One version I used to use back in Tennessee had a two-pin screw-on connector (low impedance, balanced, with the outer screw ring providing the ground). The version I have currently is the more modern, XLR-based version. AFAIK, the 2-pin version is identical except for the connector. They certain have the same sound quality. (I was able to easily patch record spots in a ten year old vocal part with my new one and you'd never be able to tell.)

 

[SRR]

The ones we used were the ??565d??, anyways original XLR connectors on all of them, some had the switch where you slightly unscrewed a plate and turned it around and the switch could move, turn it back and the switch couldn't move. After the 565's served their life, well we kept them around, but for the most part we replaced them with the original Beta 57's, and we took the ball windscreens off the 565's and put them on the Beta 57's, and tada you had a vocal mic with a proper looking vocal mic windscreen. Even after all those years Shure kept the same thread size/pattern so you could do such a thing. And this was around 1992-93. Bet you could do the same thing with a lot of their old vocal mics and a Beta 58/57a, haven't tried it myself but....