All good tube active preamps probably do improve the behavior of the amps, particularly dynamics, because they have sufficient drive compared to resistive passive linestages or op-amp DAC outputs.
However, and this is a big however, removing them from the signal chain is even better.
What you must understand is that some DAC volume control technologies do not "replace" the active preamp, they actually eliminated it. There is actually no preamp circuitry in the signal path at all. It is exactly like connecting the line-out of a DAC directly to the amps.
When you do this, the distortion, noise and compression that is in every active preamp, even the most expensive, is eliminated. Sound quality is a LOT better IME, particularly when the drive of the DAC is sufficient, like the drive (current) of an active pre.
Steve N.
Empirical Audio
However, and this is a big however, removing them from the signal chain is even better.
What you must understand is that some DAC volume control technologies do not "replace" the active preamp, they actually eliminated it. There is actually no preamp circuitry in the signal path at all. It is exactly like connecting the line-out of a DAC directly to the amps.
When you do this, the distortion, noise and compression that is in every active preamp, even the most expensive, is eliminated. Sound quality is a LOT better IME, particularly when the drive of the DAC is sufficient, like the drive (current) of an active pre.
Steve N.
Empirical Audio