Source XLR to Balanced Preamp will increase gain?

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?

Assuming you are referring to an active (not passive) preamp, when its volume control is at max its output voltage will usually be several times or more greater than its input voltage, regardless of whether balanced or unbalanced connections are used. In other words, an active preamp applies significant gain to the signal internally, for both types of connections, when its volume control is at max.

Regards,
-- Al

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?

^^ No. It depends on how the output of the CDP is set up.

If balanced but not differential, then you will see double the voltage. But if the output is differential and floating (for example, if an output transformer is used in the CDP), it may be set up so that the voltage from pin 2 to pin 3 of the XLR is the same thing as what is seen across the RCA jack.

So you will want to check with the manufacturer on this one.

Thanks, Milpai. Adding to Ralph's response just above, I'm not certain that it would be safe to assume that a TVC will necessarily be designed to provide unity gain at its max volume setting, for either kind of input (RCA or XLR). I wouldn't be surprised if at least a few of them are designed to provide a few db or more of voltage stepup at their max volume setting. (As you most likely realize, a transformer can be designed to boost voltage, although it can't boost power).

And to add further uncertainty, I'm not sure that different manufacturers are always consistent with respect to whether amplitudes and gains for balanced interfaces are specified with respect to the voltage on each leg, or to the voltage difference between the two legs (which of course would be twice as much).

Regards,
-- Al

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.