Preamps with variable gain... pros and cons?

On the Rowland Synergy IIi, increasing the gain and decreasing the output volume by a similar amount causes a noticwable improvement in dynamics.

For years I used a Pass Aleph P which has this feature. The idea behind it is to optimize your system's gain structure. The preamp sounded best when the gain was high and the volume control attenuated least. The feature is not absolutely necessary, but it does allow for a level of added refinement.

the best budget preamp in that issue is mccormack micro line drive that has three active modes of operation 0dB, 6dB and 12 dB of gain and completely passive where you can use it with no power supply.

i did not research a tube preamps on that issue but everything is possible there since even for small signals you can use switchable to tetrode operation thus increasing the gain or decreasing back to triode...