Very few turntables have built in phono preamps, but if you have one that does you would not plug it into the Rotel phono input. Instead you should use one of the high level inputs (CD, AUX, etc.).
phono pre-amp question
I have a Rotel RC1070 pre-amp, which has a built-in phono-pre-amp. Given that, can I use only turntables that do not have a built-in pre-amp, or can I use either type. If I can use a turntable that has a built-in pre-amp, how do the two pre-amps work in relation to each other? Thanks