Topic: Radio interference with CA-9100

[stgomez91]

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?

[Belexes]

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?

[stgomez91]

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.

[Belexes]

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..

[vanark]

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?

[Seth01]

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!

[owainturner]

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.

[Seth01]

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.   

[dorrcoq]

...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.

[Seth01]

...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     Why am I not surprised that you said that.     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.