Lectrosonics SMa “boiling”

[Alexander Romanov]

Hello everyone, there is a problem with my SMa transmitter, when the audio level is less than 15, noise like "boiling" comes along with the voice, the problem appears suddenly, sometimes it helps to pull out lavalier microphone and insert it back, maybe someone else had such a problem?

[Philip Perkins]

Tried other mics?  Clean contacts?

[Alexander Romanov]

Clean contacts, I use Sanken Cos11 with different wiring, it's in the transmitter, when I raise the level to 20 it disappears,

[Derek H]

Time for service. 

[jpb2]

What I think of as a "boiling" sound is usually bad contacts or a (failing) bad capacitor.

[mikewest]

Look in the 5 pin mike connector on the transmitter

 

Often dirt collects there and causes this problem

 

Use a blower and maybe a squirt of DeOxit

 

mike

[LarryF]

Hi Alexander,

The 5 pin isn't the problem since the hiss comes and goes and disappears with increasing gain, but as Mike suggests, it's always good to keep the 5 pin connector clean. Sweat, rain and Coca-Cola ends up in there as the transmitters go through various users. Alcohol on a thinned down Q-Tip works pretty well or cotton on a toothpick. Don't flood the connector. We try to seal them but it is not 100% effective. You may have to blow a strand or two of lint out after you finish.

 

I suspect instability (oscillation) in the mic gain stage when the gain is below 20, particularly since it "stabilizes" sometimes when you unplug the lavaliere.

Best Regards,

Larry Fisher

[Alexander Romanov]

Yes, and another observation: the longer the transmitter operates, the more likely the problem ,

 

[afewmoreyears]

MAYBE..The more the battery depletes, the worse the data travels over a connection that is dirty I would imagine..  That being said, the trans. is supposed to deliver the proper voltage till shut off... so... I really don't know..

[Alexander Romanov]

Upg. The 5-pin connector has been replaced and the problem has disappeared,