For Krell owners, keeping the amp on all the time?

Not a Krell owner, but I don't think it matters with this question.

I leave all solid state audio equipment on 24/7 unless I am out of town or there are lightning storms predicted for my area. (Amp, Pre and CD player) I turn on my turntable and phono-pre thirty minutes prior to using them so that they can achieve thermal stability.

Personally, I think the power up and down cycling is more likely to cause problems than leaving them on full time. Most of the items are pre-owned so warranties mean very little to me or do not apply. This may not be energy efficient but hey, you are not paying my power bill.

I usually leave all of my solid state equipment turned on and the 400xi should cause no problems. Now I wouldn't recommend this with Krell's big boy class A type amps due to the idle current draw and heat dissipation issues.

There are a million Audiogon threads that discuss the issue of whether to leave gear on 24/7 or to turn it on and off, and you should research them. Generally speaking, turning equipment on and off is in fact bad because it exposes it to thermal cycles, i.e., heating up when you turn it on and cooling down when you turn it off, which damages components over time. There are exceptions to the rule, however, for example, if you owned a class-A biased amp (Krell made many of them), it's best to turn them on and off because they run extremely hot, which is generally bad for components, and they burn too much electricity and heat up listening rooms to leave on 24/7. The only maintenance and longevity issue with leaving normal solid-state gear on 24/7 is that it reduces capacitor life, but caps are relatively easy and cheap to replace, and you can still expect to get many years of life out of them. This is greatly preferable to the failures that will result from turning components on and off, such as output transistor failure, which is expensive and complicated to deal with.

Many manufacturers will not advise users to leave gear on 24/7 because of liability issues, but many take the risk and do not even include on/off buttons on their gear - if it's plugged in, it's on. Other manufacturers offer a standby feature, but it's often done for marketing (i.e., to appeal to people that do not know any better), for example, putting many Audio Research CD players into standby does nothing more than turn off the display and mute the outputs - all internal circuitry remains powered up, as it should be.

Of course, it wastes electricity to run gear 24/7, but that's a different issue. And all equipment must be unplugged - not just turned off, but completely unplugged from the wall - in the event of electrical storms and when you leave your home for longer periods such as vacations.

Many amps (pre's & cdp's/ dac's) works like this, they just mute the output stages and dim the display. JRDG, Wadia (CDP) aso aso.., why don't you just check what the manual says about idle power consumption if you are worried? That piece you have is pretty small if compaired.

I would assume "standby" and off are two different things. Seems to me that standby would probably be a prudent compromise.