Preamp output voltage?


Could someone please explain preamp output voltage? What effect (if any) does it have on amplifier performance, S/N ratio, dynamic range, and most importantly, subjective listening? I have an old Adcom GTP-500II tuner-preamp with a rated output of 2.0V RMS and a peak output of 10.0V RMS. I am considering replacing the Adcom with a new AV surround receiver, and I would use the pre-outs to power my front KEF 104.2's with an Adcom GFA-555II amp. I am looking at the Outlaw 1070 receiver, but it only has a pre-out voltage of 0.76V. The Yamaha RX-V657 receiver claims a pre-out voltage of 2V. Will either of these receivers (or any other receiver) be likely to sound as good, driving the Adcom amp, as the Adcom tuner-preamp for 2 channel music?
javachip
P.S. -- Thanks to all for the feedback on pre-out voltage. I am seeing numerous comments in the Outlaw forums about how the 1070 needs to have its volume knob and/or channel trim controls turned up higher than usual to get a decent volume. This would seem to be consistent with the fairly low reported pre-out voltage.
Javachip - what did you decide on? The Emotiva or the Outlaw? For some reason I was unable to post a request for opinions on the Emotiva DMC-1 pre/pro, so I am going to try to piggy back here!

I know nothing about the Emotiva products and just wonder what reviews you may have read that made you decide for or against the Emotiva Ultralite you were considering.

Holly
I wouldn't fret about the output voltage from the preamp. In many cases the older units had higher outputs to justify the low S/N numbers and get above the internal noise. I have moved from the Adcom 555II preamp to the Outlaw 990 pre/pro and am very satisfied. I am also driving an Adcom 555II amplifer into JM Labs Daline 6.1 speakers. The outlaw will drive your amp just fine with actually less noise. Yes you'll have to turn up the volume knob a bit more. Sounds great though.