I've noticed an annoying buzz with an HMN1038 desk mic attached to a Maxtrac. Mic audio seems clear -- but the buzz is a problem. The buzz level varies when slightly repositioning of the coiled cord. Doesn't happen when I use a known good hand mic. The mic is fairly old but has been well maintained. No visible strain or damage to the cord or circuit board. Anyone else experience this problem with this particular mic? And if so, what did you do to fix this? ANy suggestions will be appreciated.
Thanks --- Norman
Annoying buzz using HMN1038 desk mic
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Re: Annoying buzz using HMN1038 desk mic
Is the power supply that you're using with the Maxtrac an Astron desktop model? I've had problems with fields created by the power supply's transformer causing buzz problems with HMN3000_ desk mics. Have you tried moving the desk mic away from the power supply if it's a tabletop model?
Re: Annoying buzz using HMN1038 desk mic
This IS a known problem in the HMN1038 desk mics, and most that use the same plastic housing and circuits. There is NO shielding so the mic circuits pick up any magnetic fields or induction very easily. They pick up RF fields too.
Some are partly 'cured' by grounding the case of the electrete element to add shielding. Problem there is the mic element housing is aluminum so it can not be soldered to, and the crimp to the - terminal goes bad.
We have changed all that type of 'desk' mics out due to this problem, not what you wanted to hear. And also due to very poor acoustic performance.
Some are partly 'cured' by grounding the case of the electrete element to add shielding. Problem there is the mic element housing is aluminum so it can not be soldered to, and the crimp to the - terminal goes bad.
We have changed all that type of 'desk' mics out due to this problem, not what you wanted to hear. And also due to very poor acoustic performance.
Re: Annoying buzz using HMN1038 desk mic
Al & Will -- thank you both for your fast replies!
Yes, the power supply is an Astron RS35M. Moving the mic's coiled cord around does affect the buzz level. I tried moving the power supply onto the floor with the mic and radio on the table but that didn't make any difference. Interestingly, draping the bulk of the coiled cord over the top of the Maxtrac including part of its heat sink seemed to eliminate the buzz completely. That of course is impractical and probably not very good for the radio either.
Thanks for letting me know that the buzz is a know problem. That's disappointing because I always admired these mics (they look so cool) and I finally got one. It was used so I was afraid I got a bad one but apparently I'm not alone.
Will -- which model mics did you eventually replace the HMN1038s with?
Yes, the power supply is an Astron RS35M. Moving the mic's coiled cord around does affect the buzz level. I tried moving the power supply onto the floor with the mic and radio on the table but that didn't make any difference. Interestingly, draping the bulk of the coiled cord over the top of the Maxtrac including part of its heat sink seemed to eliminate the buzz completely. That of course is impractical and probably not very good for the radio either.
Thanks for letting me know that the buzz is a know problem. That's disappointing because I always admired these mics (they look so cool) and I finally got one. It was used so I was afraid I got a bad one but apparently I'm not alone.
Will -- which model mics did you eventually replace the HMN1038s with?