R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: JM37DP Thumping noise with DBX 376  (Read 2351 times)

0dbfs

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 405
JM37DP Thumping noise with DBX 376
« on: March 14, 2008, 05:51:14 PM »

Hi,

I purchased a Joe Meek 1Q channelstrip a while ago and it came with an LDC to my surprise. The JM37DP. The mic has a -20/-10/0 pad switch and an omni/cardioid switch. It is sort of short and fat in shape.

I wasn't aware that the preamp included a mic so I was happy to have another mic to add to my closet. Even if I didn't really  have a particular need for it. Once I received the preamp I went in and tested it out to make sure it passed signal with all my mics and confirmed that all of the eq bands, compressor, etc worked as expected.

That was all fine.

I also checked the mic through my other pre's. UALA610's, API, spirit digital console pre's, etc... Everything was as expected.

Just this morning I received a DBX 376 channelstrip and started to go through the same tests to confirm everything was ok. The mic I had right next to me was the JM37DMP so I started the tests with that mic...

With phantom engaged on the 376 the JM37DMP started thumping... Thump... Thump.... Thump..... over and over... No useable signal....

I thought that was strange so I tested a couple other mic's... Both condensers and dynamics... Some 421's, U89, 57, NT1's, D112.. And they were all fine going through the DBX.

Back to the JM37P through the DBX and the same thing.. However, when I engage the pad (-20) on the DBX the thumping goes away and I can get audio out of that mic. Changing the pad on the mic didn't do anything.

So, I tried the JM37P again through my other pre's and it's fine...

I took the mic apart and there were no obvious bad connections. Looked inside the DBX and it looked fine too.

My first thoughts are that this is some sort of issue with the phantom supply and that mic in particular. Like it's pulling too much current for some reason or another. None of the other mic's appear to have the problem though and I wouldn't think that the current requirements would be that demanding or that the DBX would not normally have adequate current available.

I would like to figure out which is the source of the problem and fix it if anyone has any ideas.

I don't find the JM37P particularly useful but since I have it it would be nice to have the option to use it with the DBX pre for when I do go to put it up on a session...

Any thoughts?

Thanks in advance,
j
Logged
Jonathan Burtner
Music is Everything!
Audio is Everything Else!

MagnetoSound

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2589
Re: JM37DP Thumping noise with DBX 376
« Reply #1 on: March 19, 2008, 10:20:10 AM »

Hi Jonathan,

Have you measured the voltage of the phantom coming out of the dbx?

It might just be a little low for that particular mic. (Although 48v is the accepted standard, in practice, manufacturers do not always care enough about this!)

Just a thought. Smile


Dan
Logged

Music can make me get right up out of my chair and start dancing or it can get me so pumped up I have to walk around the block.
It can also knock me back and make me sit there and cry like a little baby. This shit is as powerful as any drug!!!
- Larry DeVivo

0dbfs

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 405
Re: JM37DP Thumping noise with DBX 376
« Reply #2 on: March 20, 2008, 10:10:37 AM »

Hi Dan,

Thanks. I'll measure it and post what I find here.

I would think that the DBX should normally have 48V but anything is possible.

Thanks!
-j
Logged
Jonathan Burtner
Music is Everything!
Audio is Everything Else!
Pages: [1]   Go Up
 

Site Hosted By Ashdown Technologies, Inc.

Page created in 0.019 seconds with 16 queries.