Warm-up time for amps and preamps

keeping your equipment on 24/7 is the best way I know of to decrease the life expectancy of your equipment, big time!  Heat is the killer of electronic components.  Heat is generated by tubes, high wattage resistors, high current output transistors etc.  This is why fans / heat sinks etc. are incorporated.  If you have ever looked at a PCB with high wattage resistors attached you will see darken areas where they are, plus cold solder joints forming.

The electrolyte paste in power capacitors, will dry out if just setting on a shelf or in equipment not being utilized.  Sometimes you can bring a electrolytic back to life by reforming it with a voltage source that is regulated.

Bottom line , to turn your equipment off when not listening is the best service you can do to your equipment.  But don't just let it set for months on end without operation.

All audio equipment electronically speaking, will be up to full reproductive audio response after a minimum of ten minutes.  Resistors, capacitors, diodes, solid state devices, etc. do not have a warm up period or break in time.  The only component that can benefit from time on is a valve tube.  because of the electrons boiling off the filament, increase conductivity with longer on time.

Tube equipment will begin to degrade over time do in part to an oxide coating that develops on the filament, not allowing for full conduction of the electrons to the grid and plate of the tube.

There are many "authoritative" answers here.
i wonder which ones are right.

The designer of my tube integrated said that it's fully warm and stable after 15 minutes.  I'll give it at least 5 before starting any playback, and 15+ before sitting down for a listen.

My DAC/Pre (no tubes) stays on 24/7.

My office system has a Yamaha 2-ch receiver I bought in 1996.  I've only turned it off about seven times, ever -- and it still sings. 

I believe rvpiano said it best. There’s been lots of threads about this already. One member mentioned awhile ago that a SACD player needs to be on for about 2-3 days to sound its best. Others have stated that SS gear needs to be on 24/7 unless not listened to for several days to a week. As much as I listen, I leave it all on 24/7. Everything is barely warm, at best. In fact, I can hardly feel the difference.

All the best,
Nonoise

Leave it on for extended life in many instances. My Class D amp runs very cool so heat is not an issue. Small preamp signal tubes last longer on as studies and real life experience show. Turning the tubes on and off often reduces tube life faster than just leaving them on. As always it depends on the design with no blanket statements applying to all gear.