As I was saying, what if that Manhole is right outside your house/apartment, then you might ended up with a toasted car and a well toasted Stereo System. Hey, you left your equipments on anything can happen right? who to blame now?
I have found that a long time on IS better. After 24 hours or so, the sound is more open, greater detail, more 'air' around instuments in soundstage.
The downside is that if one is not home and a failure occurs, one could have a fire (smoke detectors help) However, no power amp tube equipment should be left on unattended.. It is way more likely to possibly blow and start a fire than non-tube stuff. (but even tube amps are pretty safe. Though tales of tube pyrotechnics and fires are out there)
I do dispute that equipment left on has a shorter lifespan. The usual solid state product will not have any problem being left on 24/7/365. I even leave on a tube preamp I use as a digital buffer, 24/7 though it definitely will have a shorter tube life doing so. (it is in a sealed case,and if a fire started inside, would die out in a short time for lack of oxygen)
Another downside, if an electrical problem from A/C or lightning happens, more likely to toast the products, (but if items plugged in and turned off will STILL be toast, I use power conditioners with lightning protectors. The Furman REF 20i I own had a $100,000. guarantee to protect equipment for the first 5 years!!)
I used to leave all on, and now only turn off the amplifier for the powersavings, and NOT for any other reason. (And I leave the amp on some of the time anyway, for days at a time.)
So benefit: better air, better HF sound in general.
Downside: A/C power wasted. (My system uses about $25. of electricity a month, whole thing being left on 24/7, if it was all turned off when not in use, i would be spending $15 a month less. The $15 a month I would be spending a LOT more for some diddley tweak that did something as good as leaving it all on.
Lastly, the idea that equipment left on (at least all solid state stuff) wears out faster if left on is not true
Added: after reading a bunch of papers via Google on: "electronics mean time to failure vs temperature" and the like.....
The most interesting comment is:
"The stressor that has THE MOST PROFOUND EFFECT on product life is thermal cycling". So turning it OFF AND ON repeatedly is way harder on stuff than just leaving it on.
HAH.(I was sure I was right...LOL)
Then also do not have your electronics stuff next to a hot steam radiator seems like a good idea too.
I agree that over 24 hrs left on really worked for a Plinius SA100 MKIII I once had. It turned magical after being left on a day or two.
Class D amps can be left on permanently. My Gilmore Raptor monos do not even HAVE an on/off power switch, only a mute button. The manual says to leave them on 24/7 for best sound.
My amp sounds better after 30-45 minutes of being powered on. I have experimented with leaving it on for weeks at a time, but I haven't noticed any improvements in SQ by doing so. So now I turn it on first thing in the morning, and turn it off at night before bed.
FWIW, I have another component that, when left on for days or weeks, actually sounds WORSE. Strange but true.
Wow Bryoncunningham, you have an interesting component there. My system sounds worse only after I had a few drinks. I guessed there are more upsides from leaving them on 24/7. From now on, I might start leaving them all ON and hope that I have a deep pocket for replacements just in case something happened. I do have a deep pocket, but it has holes in it and I still can't find a Tailor to sew it up for me yet guys.
the benefit might be a hefty contribution to your local power company.
otherwise if you ascribe to the "warm up" theory, you eliminate the warm up period so that , in theory, the sound of your stereo is optimized.
i would think twice about leaving tube preamps, amps and cd players in the on mode, all the time.
Huh! my system sounds better after a few drinks,what am I missing here.
All my components stay on 24/7/52. Brake down rate is now non-existent . Elizabeth's research , about thermal switching seems sound . Large solid state power amps usually sound better ( smoother ) after a few days use . Power bill increased by $10. per month , not much in a six digit system . System always sounds better after copious amounts of red wine . If you have tubes disregard the above . except the wine . Tim
One last thing guys, besides the high Electric bill to pay. After 10 hours or so, not just my Amp is hot but almost the entire room's temp is definitely raising. I think the class A amp will do that to anyone not just me as I am using a Pass X350, you know how hot that thing is.
When I first got my monoblocs, I left them on 24/7 because of what I read on Audiogon. After I got my first electric bill, I nearly had a cow, so no more 24/7 for me. It sounds good right from the start without any warmup. It possibly gets better after a few hours of warmup, but I really don't pay that much attention as to whether it sounds better with or without warmup.
Nguyen357, if your system sounds worse after a few drinks, you're drinking the wrong thing. Good cognac or 12 year old Scotch will do the trick. The older the Scotch or cognac the better.
Regarding MTTF in electronic systems, numerous factors come into play. Thermal cycling can have an effect, but it depends on what the low and high temps are, what kind of parts we're talking about and how much they're derated, etc. Leaving your gear on will wear down certain types faster (class A power amps come to mind) due to current flow and hence electrochemical migration. So depending on what kind of gear you have, how it's designed, and how you use it, turning it on/off vs leaving it on is truly component specific; making a blanket recommendation is not possible.
FWIW - I work as a reliability engineer in the semiconductor industry.