The CS600 has a "preamp in", but I don't see a preamp out. It has a tape, (recording) out. Looks like you can use the power amp seperately with a preamp, but not as a preamp alone. See link below:
http://www.lebenhifi.com/products/cs600.html
http://www.lebenhifi.com/products/more-img/cs600_1_l.jpg
http://www.lebenhifi.com/products/cs600.html
http://www.lebenhifi.com/products/more-img/cs600_1_l.jpg