[Elecraft] KX3 with NaP3 USB Noise

[F5vjc]

I've purchased a USB Creative Blaster X-FI Pro for use with my Acer Win 7
laptop with the intention to use it with my KX3 driving NaP3.

This works fine until I connect the Elecraft supplied KX3 USB serial cable
to provide CAT control of the, when connected it introduces unacceptable
noise in the KX3 audio and many spurs on the NaP3 display. I have tried
bonding the laptop chassis to the KX3 with no effect.

Is there a fix for this? I know of a mod to this soundcard (additional
decoupling caps) and/or isolation of the KX3 IQ output by transformers, is
this likely to cure the problem?

Any advice on this, thanks.

73 F5VJC