A very nice bonus I just realised about the Audigy (that for some reason I never thought about before) is that it has a digital out, and the Akai hifi I have my PC connected to has a receiver with two digital inputs (that I've never used as I have my other equipment connected via optical to my Sony reciever).

So I thought I would give it a try. And it worked using the same cable I had been using for analogue audio. I moved the 3.5" jack from the analogue output of the card, and plugged it into the digital out. Then I disconnected the two phono conenctors from the other end of the cable from the receiver and connected the red (right-hand one) into one of the digital inputs on the reciever and it worked! Sounds really good.

So glad I installed the Audigy card now. Audio now being output via digital to the reciever means no interference at all and much better sound quality.