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Gefell m71 RF issues... anybody got a solution?
Old 28th June 2005
Here for the gear

Question Gefell m71 RF issues... anybody got a solution?

This is my first post here and I hope I'm not posting in the wrong place.

I recently acquired a pair of Gefell m71 mics... I think they were made in the early 90's... they sound great...silky top end and incredibly easy to maneuver.
However they have a problem with RF and I end up hearing a lot of Mexican radio stations and what I am assuming is AM chatter creating a nasty noise floor when recording quiet and subtle tracks.

The guy that sold them to me included a pair of cables that were apparently used to fix the problem. I discovered this when I tried using some of my own canares cable and discovered the nasty radio noise dramatically increased.

Lately though, even the new cables are not preventing the radio from interfering...

I was wondering if anybody knew how to eliminate the RF issues or if there was a fix for such things. I would love to mod these to make them quieter if it all possible but I'm rather clumsy in the electronic tinkering dept.

Any help, thoughts or suggestions would be greatly appreciated...

Old 28th June 2005
Lives for gear
C/G's Avatar

Contact Jim Williams @ Audio Upgrades. He has them listed on his site as something he modifies. He usually changes out the FET in there too and some caps and resistors. I was going to send him mine to get better resistors put in, but they are quiet as a mouse so I did not.
Old 17th February 2009
Gear Maniac
chribble's Avatar

late response i know

i have a bunch of canare/neutrik here L-4E6S on all of them.

i used a shorter cable and that helped for some reason.

it was pissing me off so i thought id post this as a fix.
Old 17th February 2009
Earlier Gefells lacked any rf protection or filtration. This can be added by soldering a pair of .01 or .022 uf caps from pins 2 and 3 to pin 1 on the XLR inside the mic. If problems still occur, use larger surface mount mono ceramics instead of through hole caps and solder them across these pins.

Jim Williams
Audio Upgrades
Old 12th December 2009
Here for the gear

Thanks Jim Williams for useful info..heh
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