Is there a problem with operating an amp long term at or near its max gain setting? This question came up in another thread as an aside sort of issue and it got my noggin joggin.
So the context is using EQ software to balance out some of the warts in sound profile from a set of headphones. With some of the presets out there for EQ, a negative preamp gain is inserted, which can result in a very quiet signal to the amp, and in order to make up volume, the amp gain gets turned up.
If this results in running the amp gain at 80% or even more to drive the desired listening volume, is it bad for the amp?
as with anything, running it close to peak may put some undue stress on parts that cause a component to fail…but 80% should be okay for the most part. you may just want to figure a way to ensure there is good air flow around it so no heat buildup can pool around it.
So much like other electronic components, heat rather than duty cycle is enemy no.1?
Running at nominal load should not negatively effect any device.
With some devices, you have limited operation time before having to let it cool down (power tools designed for home use are an example of this).
Unless it is badly designed, the volume knob (or gain settings) should not have any effect on service life.
HiFi equipment is often a bit lacking in the protection department, like @Marzipan said, heat management is to be considered.
I would never run an amp for prolonged periods at 90% or higher just as a rule of thumb. But any amp worth its salt should be able to run at 80% for as long as you want it to without adverse effects.