Source XLR to Balanced Preamp will increase gain?

Thank You for your perspective on the XLR connections.
The thing that seems tricky is that some CDPs mention the same output level 2.2V (for example) in both RCA and XLR connections while some other CDPs mention exactly twice the output level in XLR compared to RCA. This seem to correspond to the 6db higher output level that you mention here.
From an article on the web, I got this formula:

3dB = doubling the amplitude. If you have a reference signal at 1 volt, 3dB is 2volts, 6dB is 4 volts, and 9dB is 8 volts.

With that in mind, if I choose a CDP with say, 4V output at XLR, will it mean that my amp will ultimately see 8V at the MAX level of the preamp's output?

Al,
As always, useful feedback.
I was actually referring to my TVC, which is passive. Yes, active preamps do increase the gain. But since TVCs are just attenuating the voltage, I assumed that the CDP's 4V at XLR, is 4V at each +ve and -ve leg. Hence that would mean 8V at the amp end when the volume on TVC is set to MAX. Is this correct assumption?

Ralph,
I am not so tech savvy. Thank You for the heavy dose. I want to learn more. Can you please explain "differential" and "floating"? I understand that pin 2 is +ve while pin 3 is -ve. Based on your explanation I am tempted to try a RCA to XLR adapter on the IC that goes from my existing CDP to the TVC. I believe in this case the voltage that the TVC will remain at 2V instead of 4V which a true XLR designed CDP would provide.

Al,
My TVC is set for unity gain, as I had not opted for the 6db gain.

Ralph,
Thank You very much for the detailed explanation. Made it so much easier to understand the "real balanced" concept.