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#1
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A really bizarre microphone grounding problem... any ideas?!
wrote:
I have a pair of oktava mk319s which i have modded as per the scot dorsey article. Oddly though since modding one of the grills has caused whichever mic it is attached to, to suffer from severe ground hum. It's probably not ground hum. It's probably some kind of RF noise. I have checked grounding continuity between pin 1, the earth track on the board, and the the grill basket and in any combination of mic and grill all appears to be in order. What if you cover the grille with aluminum foil? Does the noise go away? when you apply the good grill to either mic it sounds lovely and the hum goes away, apply the bad grill to either mic and the problem rears its ugly head again. Something is not connected to something else, somewhere. What did you do to the grille? --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#2
Posted to rec.audio.pro
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A really bizarre microphone grounding problem... any ideas?!
On Oct 12, 6:19*pm, (Scott Dorsey) wrote:
wrote: I have a pair of oktava mk319s which i have modded as per the scot dorsey article. Oddly though since modding one of the grills has caused whichever mic it is attached to, to suffer from severe ground hum. It's probably not ground hum. *It's probably some kind of RF noise. I have checked grounding continuity between pin 1, the earth track on the board, and the the grill basket and in any combination of mic and grill all appears to be in order. What if you cover the grille with aluminum foil? *Does the noise go away? when you apply the good grill to either mic it sounds lovely and the hum goes away, apply the bad grill to either mic and the problem rears its ugly head again. Something is not connected to something else, somewhere. *What did you do to the grille? --scott -- "C'est un Nagra. *C'est suisse, et tres, tres precis." Cheers for the replies I'll try the aluminium foil idea when i get back at the weekend, "What did you do to the grille?"-hehe, exactly my thoughts! ruined it i think may be the answer! I've obviously done something wrong but what exactly? I have removed 1 layer of mesh from the top and sides of the baskets and taken out the side bars of the grill cases. Effectively leaving 2 rings holding the grills in place. The reason for thinking that it is a grounding issue is that the hum is constant, loud, around 60hz and reduces when you handle any part of the mic. Thanks in advance for suggestions Ben |
#3
Posted to rec.audio.pro
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A really bizarre microphone grounding problem... any ideas?!
wrote:
The reason for thinking that it is a grounding issue is that the hum is constant, loud, around 60hz and reduces when you handle any part of the mic. The giveaway is that it reduces when you handle any part of the mike. There is not solid connection being made between pin 1 and the case. If it were a problem with the grille itself, touching the mike would not change the noise. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#4
Posted to rec.audio.pro
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A really bizarre microphone grounding problem... any ideas?!
Keep in mind that the capsule and anything before the FET is supa-dupa high
impedance (we're talking giga-ohms) and requires the grill as part of the faraday shield to stop it inducting noise. You need to ensure it's well bonded to the body of the mic. Bill. wrote in message ... On Oct 12, 6:19 pm, (Scott Dorsey) wrote: wrote: I have a pair of oktava mk319s which i have modded as per the scot dorsey article. Oddly though since modding one of the grills has caused whichever mic it is attached to, to suffer from severe ground hum. It's probably not ground hum. It's probably some kind of RF noise. I have checked grounding continuity between pin 1, the earth track on the board, and the the grill basket and in any combination of mic and grill all appears to be in order. What if you cover the grille with aluminum foil? Does the noise go away? when you apply the good grill to either mic it sounds lovely and the hum goes away, apply the bad grill to either mic and the problem rears its ugly head again. Something is not connected to something else, somewhere. What did you do to the grille? --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." Cheers for the replies I'll try the aluminium foil idea when i get back at the weekend, "What did you do to the grille?"-hehe, exactly my thoughts! ruined it i think may be the answer! I've obviously done something wrong but what exactly? I have removed 1 layer of mesh from the top and sides of the baskets and taken out the side bars of the grill cases. Effectively leaving 2 rings holding the grills in place. The reason for thinking that it is a grounding issue is that the hum is constant, loud, around 60hz and reduces when you handle any part of the mic. Thanks in advance for suggestions Ben ** Posted from http://www.teranews.com ** |
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