Any old twin core cable will do - it's a differential signal pair and interference is not an issue. The power levels are relatively high so any loss of signal strength at the connection points is so low as to be not significant.
If you ask in the hi fi shop they will be sure to have something very expensive that is "just what you need".
Peccavi
July 2010
Go to your local HI-FI dealer, he will recommend the best cable for your system and budget. The more you pay the better the the quality. Different cables suit different amp / speaker combinations.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cassette players.