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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: stgomez91 on March 29, 2011, 07:52:08 PM
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I have a show tomorrow that I need to record and in testing my new CA-9100 out I've noticed that I get a strong radio signal that makes the recording sound terrible. Here's what the situation is:
I set up the deck and the pre-amp on my bed about 5 feet from my stereo and turned up my turntable to test the levels. When I put the headphones on I heard the music as well as interference. To make sure it wasn't just the music, I stopped the record and listened: LiteRock 105 was playing (local radio station). To find out where it was coming from, I unplugged the preamp from the deck. Now I just had the headphones and the deck: no sound, as expected. I then connected my headphones to the preamp: LiteRock again. So it's definitely the preamp.
I've searched the forums and haven't been able to find an answer. Also, per iGene's advice, I tried wrapping the preamp in aluminum foil but I didn't notice a difference, though when I did put the aluminium foil into the input I got a real strong FM signal.
Am I the only one who has had this problem?? How can I stop this or combat this?
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Are you running some mics from the 9100? There is a common problem with cell phone interference from poorly shielded cables that has been discussed at length here, but that is a mic issue and not a pre-amp issue and only deals with cellular signals.
Would you be near an FM receiver at a show that this would be an issue?
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I'm running a pair of CA-11's to the pre. Tbh, I don't know much of what shielding is. I wouldn't know if I'm going to be near any FM receivers at the show...I've never been to this venue.
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You should be fine with CA-11 > 9100 > deck. I run this all the time with CA-14's and other CA mics without issue of interference and that is in venues with lots of cell phones, wireless in-ear monitors, walkie-talkies (crew), etc..
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I've never seen this problem with my CA-11 > CA-9100 > R-09.
But, perhaps it is a poor/loose connector/cable? Are you certain the cables are properly seated in the preamp? What kind of cable are you using to go from the CA-9100 to the recorder?
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You should be fine with CA-11 > 9100 > deck. I run this all the time with CA-14's and other CA mics without issue of interference and that is in venues with lots of cell phones, wireless in-ear monitors, walkie-talkies (crew), etc..
Sadly, I can confirm that I've had a few masters ruined using the the above rig.
I've never seen this problem with my CA-11 > CA-9100 > R-09.
But, perhaps it is a poor/loose connector/cable? Are you certain the cables are properly seated in the preamp? What kind of cable are you using to go from the CA-9100 to the recorder?
When I use that set up Rory, I never have issues either but I did get cell phone RFI with my CA-11 > CA-9100 > H4n. Picked up some just the other night as I was taping 4 channels all into the H4n. Strangely, it came through my CA-11 cards but not my CA-11 omnis. Thankfully it was only 4 seconds but still ruins a master and my cards were getting a better pull that night too. :(
A loose connector or not firmly plugged in would produce more of a static sound, I think. Last summer when I first noticed it the RFI, I started putting my H4n into a Camel-back type water bag holder. It was plasticized aluminum foil and anecdotally seemed to work - although I didn't do any scientific testing to confirm.
Good luck!
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I've had something similar... But when I changed to higher-quality connector cable between the CA-9100 and my M10 I never had the issue again... It seemed to be the unshielded cable I used.
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I've had something similar... But when I changed to higher-quality connector cable between the CA-9100 and my M10 I never had the issue again... It seemed to be the unshielded cable I used.
I'm pretty sure that's where my "weak point" is too. Thankfully, I've just ordered some new much higher quality cables from Ted just in time for the festy season. ;D
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...it was only 4 seconds but still ruins a master
I wouldn't go that far! Easily fixed with a small patch from the other source.
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...it was only 4 seconds but still ruins a master
I wouldn't go that far! Easily fixed with a small patch from the other source.
Hahaha :P Why am I not surprised that you said that. ;D Yes, you're right it's not the end of the world and is fairly easily replaced by my second source but the omnis didn't get as nice a pull as the cards so anyone with decent ears will hear the (short) difference. Plus the master is impure with that RFI. :(