Preamp output voltage...affect on volume???

If they both start a 0 and attunuate at .5db to max all it means is that the 50 'volter will drive a far more insensitive amp and or long runs of cables with out degredation. Beware however, some amps have large initial steps of attenuation, as much (or more?)as 3db. With those you could easily run out of usable attenuation with an amp which is very sensitive or a source which is high level.

I realized I aksed my question incorrectly. What I am wondering is if given the conditions described above, will the preamp that outputs 50 vrms sound louder than the preamp that outputs 20 vrms, assuming both are set at the same volume level????

No. It won't sound louder. By using the attenuator you will have effectively reduced the output to the amp to the same level, you'll just have a lot of power in reserve that you will never use unless you have a grossly insensitive amp or one specifically designed for that pre-amp output (balanced design perhaps?).

No, it wouldn't be louder. In fact, I am willing to bet you wouldn't even use any of the gain in either one! Many preamps don't need to be set past unity gain for the loudest music level used. Exceptions are preamps with post attenuators or those mated to a highly insensitive amp, like Newbee says.

Arthur

Ok, so if this is the case, why does preamp a (50 vrms) play significantly louder than preamp b (20 vrms)? Is all due to the gain??? I am really confused because the only thing I have changed in my system is the preamp I am auditioning and the sound is already above my listening levels at volume setting "1" on the preamp (preamp a). Please explain so I can better understand what is causing the signficant difference in volume I am hearing.