[Elecraft] K3 RTTY Audio Thru External DSP

[Jim Harris]

Hi to the group and Merry Christmas
Has anyone used an external DSP (noise reduction) between the output of the K3 and a computer sound card?  What was your experience with it?  Before telling me the K3 provides all the noise reduction needed, remember the NR is turned off in digital modes.  I'm contemplating using a JPS NIR-12, Noise/Interference Reduction Unit.  
If anyone has any experience with this setup how did you hook it up?  Which output from the K3 did you use; headphone, speaker or lineout?  Which output from the DSP; headphone, speaker or lineout?  Did you use or find necessary to use an isolation transformer between the K3 and the DSP and the computer sound card?
My primary concern is to prevent ground loops.  The NIR-12 schematic appears not to have any isolation on the outputs as does the K3 on the lineout.
I would appreciate any meaningful comments.  
Take pride in the USA. 73



Jim, W0EM