[Elecraft] K3, Microham MK2R+, Rear Phone Jack = Hum

[Don Wilhelm]

Rich,

Check your cables.  That sounds like an open shield somewhere in your 
cabling.
Do you have a very early K3?  Those had inductors in series with the 
ground path that should have been bypassed.  If you do have those 
inductors, they could introduce hum.

73,
Don W3FPR

On 3/14/2014 8:39 PM, Richard Thorne wrote:
> Hello Group,
>
> I just installed a Microham MK2R+ SO2R box, I connected the HP Audio 
> input of the MK2R+ to the 'rear' phone jack of the K3.
>
> Lot's of hum on the receive audio and distortion on my monitored ssb 
> transmissions.
>
> When I unplugged the cable from the rear phone jack on the K3 and 
> plugged it into the front panel phone jack, the hum goes away.
>
> Any ideas why the front panel phone jack works without hum but the 
> rear phone jack has hum?
>
> I was hoping the rear jack would work as then I would have a totally 
> uncluttered front panel on the K3, all the cables would be plugged in 
> the rear.
>
> Any ideas?
>