[TowerTalk] [RFI] Subwoofer resolution

[Jim Brown]

On Mon, 20 Aug 2007 13:13:41 -0400, Dan Zimmerman N3OX wrote:

>It's not only microphones.  Our lab's data acquisition cards and
>breakout boxes have a pin 1 problem as well.

Yes. It's also in virtually every computer audio interface (the mic 
and line ins and outs), almost all home audio gear, and nearly all 
ham gear. My FT1000MP has RF feedback on 15M and 75M that is caused 
by a pin 1 problem at the mic jack. Nearly all RS232 interfaces have 
pin 1 problems. Most can be fixed by using the DB9 shell as the 
"ground" rather than pin 5. 

There's a lot more detail on this on my website. 

http://audiosystemsgroup.com/publish

73,

Jim Brown K9YC