taylord Posted January 22, 2018 Share Posted January 22, 2018 Hi all, We have some budget floor mics here https://www.studiospares.com/Microphones/Mics-Other/Stageline-ECM-306B-Black-Boundary-Mic_255900.htm that when when phantom is turned on to power them a high frequency noise is created. I suspect that it's due to them being cheap mics. Is there anything out there that can 'clean' the signal up. I'm currently trying to EQ it out but it's around 6-8khz so not ideal! Cheers. Link to comment Share on other sites More sharing options...
MarkPAman Posted January 22, 2018 Share Posted January 22, 2018 I doubt the phantom power is the cause of the problem, just that as they don't work without it, the problem's not there when you turn it off. If there's 6-8kHz on the phantom supply, that's a problem with the desk, but you'd notice that on every channel, I'd imagine. Have you moved the mics to different places to test them? It could be that they're close to something that's generating some interference that they're picking up. Link to comment Share on other sites More sharing options...
taylord Posted January 22, 2018 Author Share Posted January 22, 2018 Mark, the desk is a Soundcraft SI Impact, bought this time last year so hope it’s not the desk! Haven’t tried moving the mics yet, but will do. Not sure what could be causing interference as they are on the apron of the stage with nothing electrical close by. 1516638160[/url]' post='558991']I doubt the phantom power is the cause of the problem, just that as they don't work without it, the problem's not there when you turn it off. If there's 6-8kHz on the phantom supply, that's a problem with the desk, but you'd notice that on every channel, I'd imagine. Have you moved the mics to different places to test them? It could be that they're close to something that's generating some interference that they're picking up. Link to comment Share on other sites More sharing options...
sunray Posted January 22, 2018 Share Posted January 22, 2018 Check the cable wiring, I had something similar years ago where pins 1 & 2 had been flipped at both ends. ie the cables screen was on pin 2. This was on a whole batch of 100 cables. Link to comment Share on other sites More sharing options...
taylord Posted January 22, 2018 Author Share Posted January 22, 2018 Where were the cables from out of interest? Link to comment Share on other sites More sharing options...
Lamplighter Posted January 22, 2018 Share Posted January 22, 2018 You can easily prove where the problem lies. Make up an XLR plug with a 1k ohm resistor between pins 2 and 3, and a 6k8 ohm resistor between pin 1 and 2, and another between pin 1 and 3.Plug this into the mixer and check for the noise with the phantom on. If the noise is present then the mixer is faulty. If clean plug into the far end of the cable. If still clean the the mic is the problem, if noisy then the cable needs looking at.BrianPS at the far cable end it would also be sensible to check that the voltage between pin 1 and the other pins is symmetrical with the test plug connected. It should be about half the phantom voltage. Link to comment Share on other sites More sharing options...
taylord Posted January 22, 2018 Author Share Posted January 22, 2018 Where were the cables from out of interest? Link to comment Share on other sites More sharing options...
sunray Posted January 23, 2018 Share Posted January 23, 2018 Where were the cables from out of interest?I don't know, I didn't get involved with purchasing at that company.I did pick up some Klotz leads in Edgeware Road a while ago at a very good price where one end had been wired that way. Link to comment Share on other sites More sharing options...
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