If you don't think about it too hard, you'd imagine that the signals in the phono stage would be smaller than the signals in the line level preamplifier stage that follows it. Or that the signals in the DAC/CD player would be about the same level or slightly lower than the signal in the preamplifier.
As usual, the answer is "it depends". It depends on the sensitivity of your speakers, how loud you are listening, and the voltage gain of the amplifier. It also depends on whether we are talking about a MM phono stage or low output MC.
My point is simply this: the volume control is an attenuator
, and at the typical "9 o'clock" position the input signal is reduced in magnitude by about 35 dB.
That cuts it back down to being comparable to the output of a moving magnet cart, and much, much smaller than anything found in a DAC stage.
It means you absolutely, definitely, positively must spend as much effort and care...