Here is a neat article for your enjoyment. https://www.decware.com/paper43.htm
It may help you with your quest for low volume listening. It is biased to tube/SET amps, but it also works for any setup (solid state). My latest amp purchase was a 1959 Motorola tube amp that was pulled from an old console stereo. They are real sleepers.
I am using it to run a pair of Decware Imperials. based off of the 1956 Jensen Imperial Reproducer. Just bought a pair of Altec 811b horns to go with them.
I was using Tube Depot's tubecube 7 to run them. It is a neat little amp and a cheap way to try a set amp at $180. I own two. Got the second one on sale. It is a toy and the stock tubes suck. Buy some Sovtek EL84s and a 12ax7lps. I have also rolled some Amperex 8bq5 power tubes and a Raytheon 12ax7 backplate in it. All I have to say is WOW!