I'm not sure, but I beleive that the volume settings on the pre-amp for two different amplifiers will vary with the impedance of the amplifiers in question. As you play your amps more, you will notice a point during warm up in which everything just sounds better (typically about 30-45 minutes), I don't believe there is any harm playing at volume sooner, but a properly warmed up unit does sound better. I'll typically turn my system on early before anticipated listening just to allow for warm up. (Pre-amp first, and amps after the pre-amp has reached operating temperature (usually about a minute). I'll also turn on source components to allow them to warm up also. When turning the system off, amplifiers are turned off first, before turning off the pre-amp. (Essentially, your pre-amp should be in powered up and in control of your system from start up to finish). I hope this helps, Happy Listening,
