Another component to this topic is the input/output sensitivity of preamp/amp. I had a Decware Torii Junior, 20 wpc, with a preamp, Canary C630, max gain of 9db. Couldn't get over 90db volume (at 10') with preamp wide open. Tried a Rogue Audio RP-7, with 14db gain, could not get even 70db listening volume cranked up.
Input sensitivity of the Decware amp is set to 2 volts, most are 1 volt or less. So it takes twice the preamp signal to get to same volume. I now have a PrimaLuna Dialogue HP, with input sensitivity of 1.2 volts. Almost the opposite issue now, same Canary preamp, volume set at 2 of 10, dB listening volume is plenty, 85+. At 4, music transients are >100dB.