Looking for preamp w accurate/fine volume control

Over the years I have owned mostly integrated amps and only a couple preamps. Some of these, like my current Primare A30.1 have very nice volume controls that give you exceptionally fine tuning of the volume. My Bel Canto Pre3 also allowed very small changes which I loved.
At the other end, I have owned a few amps that when the remote volume was adjusted the result was a major jump in the volume. Anyone have a suggestion for a pre that offers this feature. Looking in for one at around $500 used.
How much preamp gain will you need? Active preamp gain varies from product to product, anywhere from around +6db to perhaps +28db.
Gain? I think 15 or 20db should do.
After reading your question again, am I correct in assuming that you want a remote control preamp? The Bel Canto uses digital control of an analog potentiometer and it looks like your Primare does as well. This is pretty recent engineering practice & I don't know if you'll find this in a stand alone preamp at your price point. Any non-stepped manual potentiometer in a preamp with proper gain for your system should be adequately smooth.