Jim, I highly, highly doubt it could ever damage the amps: there's just not enough power coming out of a preamp to do damage. Perhaps a really terribly designed preamp might fail.
To comment on whether the sound might change I'd have to know the output impedance of the pre, the input impedance of a single power amp, and the capacitance and resistance of the interconnect.
In most cases, with an active preamp, I highly doubt it would affect the sound. With a passive preamp, and/or power amps with input impedances under 10k ohms it might lose dynamics and roll off the high frequencies, but really you'd have to try it.
To comment on whether the sound might change I'd have to know the output impedance of the pre, the input impedance of a single power amp, and the capacitance and resistance of the interconnect.
In most cases, with an active preamp, I highly doubt it would affect the sound. With a passive preamp, and/or power amps with input impedances under 10k ohms it might lose dynamics and roll off the high frequencies, but really you'd have to try it.