I had been plagued by some on-screen noise spikes on my K3 panadapter. One of the noise spikes was mirrored approx 48KHz apart on my 96KHz visible spectrum. My delta 44 sound card has got 4 inputs and 4 outputs on it's remote head. I had been using inputs 1&2 for my I&Q from the Softrock.
To make things easy, I had purchased an audio splitter lead from Maplin which allowed me to plug 2x 1/4" mono jack plugs into the soundcard interface and then go stereo to the softrock via a 1/4" stereo plug to 3.5mm stereo jack lead. All in all that made 3 connections per audio channel. I decided to make my own lead with the correct connectors at either end, thus missing out the centre splitter to lead connector.
The mirrored noise spike is now history! The lesson learned, is that you can't have any intermediate connectors in the lead between the soundcard and the K3 without risking on-screen noise spike "funnies".