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

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.

Everything else being equal (and I doubt that it is) if preamp a has a lower output impedance than b it will play louder at the same setting.

What are the specs on the preamps? (BTW, 50Vrms is EXTREMELY high for a pre amp, are you sure about that?)
Do they really have the same gain?
Do they have the same taper on their volume controls?
Are you using them both balanced?
Why do you have this same basic question posted in several different threads? I think you'll get better answers if we don't have to follow 2 threads on the same topic.

Perhaps it would be helpful if you listed the preamps instead of having us guess what the problem is?

I checked their web sites but can't find any specs for gain on either of the preamps.

herman, i was told by BAT that the max gain is 17db. I am going to check the gain for the classe today...i will report back.