This is why lots of the older gear that I have had soft start circuits built into it that slowly ramped the power up on especially the higher voltage stages over a short interval of time like 10-15 seconds. That was much more gentle on the caps.
I have two amplifiers and one preamp I bought back in the late 80's (Rotel), and have used then nearly continuously for most of that time, they still work perfectly. I never left them on full time, but would turn them on and let them warm up before playing music. Apparently, good quality audio components (transistor type) will work for a very long time.
@Sonya Actually, no electrolytic capacitor is designed to last 38 years. That is not to say that you can't use them that long, but the equipment design will need to be tolerant of rising ESR. It'd be very interesting to test the old capacitors that you replaced.
I still have my Sansui stereo I bought way back in 1977. 881 receiver, SE9 compuEQ, 3060 turntable, four SP2000 speakers. Later added a Sony CD player and have my Direct TV hooked up also. Use a Y adaptor for my tablet. This stereo was bought new in 1973 and I bought it in 1977. I have played it every day for the last forty years. Still plays perfect, will still shake the whole damn house!!! I'm sixty years old and I know this stereo will still be going strong long after I'm gone. I do turn my stereo off when I'm not using it.
Again, I typically would agree with what was said in this video. But we must also keep in mind that most consumer-grade Electronics are capable of being turned on and off thousands of times without experiencing any damage or dysfunction. If you are leaving your 1000W Class A amp on all the time to extend it's life cycle you are also paying a hefty price in electric bills. When it could be cycled on and off once a day for 5-6 years without any ill affect; probably more like 9-10 years. I have a 35 year old NAD 3030 Solid state amp that has been power cycled likely 10,000 or more times in its life and it still works like brand new; and was only cleaned internally in the past 5 years. So, dont sweat the small stuff.
" If you are leaving your 1000W Class A amp on all the time to extend it's life cycle you are also paying a hefty price in electric bills"PLUS the temperature it's running on will probably dry out the electrolytic caps rather promptly.
Working with computer hardware, our biggest worry was having to shut our servers down to a complete power-off state (after running continuously for months), then prayed as we powered everything back on...
I always think of my 1995 truck that still has the factory radio, it has endured brutal summers and winters, humidity and continuous off and on. Works like a champ. Solid state stuff is solid unless a bad part fails and even that is unlikely. Rock on
Am I missing something here? (I am sure I am) Capacitors are ether charged or discharged. Capacitors are not capable of gradually release power, other wise We would not be using batteries. The materials will age, the resistors will change over time, the transistors will not open or close anymore (and the chips are just mountains of transistors squeezed in really close), ... etc and the heat will accelerate that process. That is why in iT zones the room temperature is always below 20C. A switch will never get as hot as a server but the life will get shorter as the temperature gets higher.
Thanks for this video.I would always assume that extra heat on electronics would shorten lifespans. I always run into a situation where Im terrified to use things for fear of destroying them.
I've powered on/off amplifiers hundreds of times over the years. No problems with them yet. Wouldn't keeping gear on vs turning it off be somewhere in the owners manual?
Good question. My professors are glued about this. They argued, when it comes to computers anyway, that leaving a computer on in a high humidity environment would burn off any moisture accumulating in the computer's case. So they believed that you should leave it on. I tend to believe what you are saying Paul, that the surge of current flowing into a piece of equipment the capacitors are stressed. So, my inclination is to leave things off until I'm ready to use them. I have no stand by stated in my solid state electronics. And I may not use my stereo for months at a time, not because i don't want to, but because no one else in the house likes the same music I do. So it may be a long time before I'm ready to crank up the stereo and rock out!
I think he should have mentioned Class A as exception as well. Class A sound great but are very inefficient, meaning they convert majority of the electricity into heat. I would suggest switching off/standby when not in use. Firstly it will save on your bills. From sound perspective maybe switch it on 15-20 minutes before listening so that it can warm up.
Paul's answer is correct, assuming constant clean power. If your utility provider routinely sends dirty power (spikes, sags, surges, etc), then those power issues will stress and wear out your equipment. Note that if you ever have a blackout, unplug any critical equipment. You do not want anything of value to be plugged in when the power returns. It is a good practice to wait as long as 1 hour, after the power has returned, before plugging in your gear. When power is returned, that is when the worst garbage will hit your home.
Very good advice I think. If it has a standby mode leave the equipment powered up and switched to standby when not being used and it will last far longer.
I have a PS Audio 2C+ power amp that has been on continuously for over 32 years. I've only powered it down a few times, only when moving. Still sounds great!
I'd bet turning an incandescent light on for a certain amount of hours, or turning it on and off many times, the light turned on and off would run for a shorter amount of hours. That doesn't mean that you should leave a light on for a month when you don't need to will last longer in months, but in total hours lit, it probably will. I notice most lights for me have gone out upon tuning them on.
I think it's stupid to leave on something 24/7 . For the other hand, I try to avoid to turn on several times a day an item opting instead to leave it on until I quit listening for the rest of the day. It is the most balanced use can the owner do to avoid to turn on/off several times or leave it on continuously. Rich people can allow themselves to worn out their equipment because they usually don't keep their gear so much time as the working class people whose must take more care of their hard-earned investment.
Thanks Paul for your interesting videos! In this matter I think it also has to do with for how long time the equipment is unused. No reason to shut the stereo off if you will use it next time the same day. But if you don't intend to use it for days or a week you can shut it off, or?
Hi patric J, my question is exactly the same and I wish Paul could answer us With my work schedule I never get time every day of the week to listen to the music . There are times when I can't listen music for few days in a row. So then it makes sense to keep it on ? Also if your power amp or preamp is Class A then is it still advisable to keep them on ? I am sure no one would like to keep a class A power amp for life for the amount of electricity is wasted and converted to heat But after all this the warm up time sometimes for me is also killi g as I always have to wait for that an hour or two to enjoy my music in its full glory
Excellent i feel much better now, my amp turns itself off onto standby mode and i've been worried that discharges it as i use it everyday so i would rather it just stay on, now i know this i feel much better, thanks Paul.
My Yamaha RXV2700 has been on for over 10+ years and it functions perfectly. I must have innumerable hours listened through music, shows, gaming and movies. I also use it for RU-vid and browsing the web with my relatively high end gaming pc. At its current rate I fully plan on keeping it after I upgrade to separates later this year. In short its one of the best 1k plus purchases I have ever made. I probably will be Moving to the CXA series processors from Yamaha later down the road.
@Paul McGowan What about Solid State pure Class-A amplifiers, and leaving them on 24/7 - won't heat be an even bigger detrimental factor here than the stress induced from turning the equipment on/off?
I fully respect your views and opinions on all the questions you answer from viewers, but I wish to toss in my 2¢ in. I am not a youngster. I grew up seeing the transition from tubes to solid state too. I even did a 7th grade science fair project back in 1967 on tubes VS transistors. For my display I had an old HH Scott 21-D? tube amp and a "new" Heathkit AA-15 stereo transistor amp that I build as a kit (still running strong to this day)! OK, putting all that aside, there are many logical arguments on "do I leave it on 24/7 or turn it off when I don't use it". It's all rob Peter to pay Paul as the old saying goes. That's NOT Paul McGowan! Tubes are like incandescent light bulbs. Turning them on and off frequently will probably cause the filaments to open sooner aka burn out. A major advocate of leaving tube equipment ON 24/7 was the heat issue. A tube amp is much like a car engine in the fact that it goes from quite cold to quite hot. They say an engine wears the most when it's cold. With tube equipment it's the thermal stress on all the components expanding and contracting as temperature changes. Hard on components and solder joints. The old skool method was to leave tube stuff ON as long as it's well ventilated. Never mind the power consumption! With transistor equipment, there is some truth to that same philosophy. A certain amount of heat is generated and there is some thermal stress on the parts and solder joints, but now mostly the PCB's instead of point to point. As was pointed out by Paul, and others, capacitors do take a big hit powering up. They get whomped by inrush current full speed which is hard on them. Notice your lights flicker a bit when you power up that monster amp? That's the power transformer/switching power supply and the poor filter caps getting nailed. I have actually build my own current limiting time delay relays to "ease" that inrush voltage to some of my amps. I made one for that old Heath Kit even. That thing had no protection circuits or speaker relay, so the speakers would emit a good "thump" when powered up! After I installed a current limiting circuit in the power supply B+, the thump is gone! That's because the giant filter cap gets ramped up instead of a full hit of 70 volts! OH...regarding that proverbial amp that lived in a box on the shelf for 20 years and finally gets powered up? Well, expect it to release the magic smoke! It needs to be ramped up slowly on a variac to save those caps! Heard of capacitor "re-forming"? If performing this procedure on devices with a switch mode power supply, I'd dial it up fairly quickly because these power supplies don't like too much undervoltage. But just bringing the voltage up from zero to 120/240 in a second or two will help a lot to save your stuff! As for me....I shut all my stuff down when done enjoying it. IMO it's not worth the additional wasted power consumption and a higher electric bill!
You know a lot! Everything you'd said can be bettered, it's all true. I have two monster power amps and several other gear that have not been powered on in 13 years. I knew a Variac is the correct procedure to put in use again vintage gear that have been dormant for so long but I think it is expensive, is it worth the cost/risk ratio? A Variac? Cheers
Yes . . . bought a 20 year old 300 watt amp (when bridged in 2 ch) and the only test was turning it on and waiting for the power up relay. When I hooked it up at home, only hum from the speakers. Waited a day and turned it on again. Music from input, but sounded crappy. Third day, tried again and clean sound. My concern now is to maybe run straight signals for an hour each, stepping up the frequency . . . to properly reform the capacitors. Do that before playing music at higher wattage outputs.
I agree!!!!! I have all Technics Components bought new in 1989. They all work perfectly to this day. No problems at all. My receiver has a Standby Power switch, so when I turn it off, some things are always running in the unit.
...or unless you're going away for a while, like a week or 3, right? Because then there might be a bit of saving in the length of "offness" over leaving power running through it, both in giving the machine a power rest and giving your power bill a rest. (Especially with a few or several devices.) Right?
I've got some equipment that's 35 + years old that's been turned on & off countless times and it's still perfect - and my electric bills are a lot lighter because of it too. Even my modern HiFi equipment gets turn on when needed. I might leave it on for 10 minutes before using, but that's it. If something does go wrong (incredibly rare) you get it fixed. It will be overall cheaper to fix than your long term on electric bill.
My amp uses 150 watts continuously in standby mode. 320 when in idle with a max of 3400. It gets pretty warm with just standby. I do turn it off. I know it's not recommended. But I just can't see burning all those watts 24hrs a day. If it didn't sound so good I'd get rid of it. I guess I just have to hope it doesn't go bad anytime soon.
My Yamaha amp which uses 1500 watts when all 8 channels are fully driven uses 0.3 watts in standby mode, whoever designs an amp which uses 150 watts when not in use? Does it keep all the valves heaters on all the time?
Class A amps apparently use as much power when they are on and not being used as they do when they are being used, if not more.class A/B is more efficient but still not super efficient, and class d is extremely efficient when not being used.
What about idle power consumption for units not as advanced as these. Is it true that most amps draw considerable power even while no music is being played?
I have a Meridian 588 CD Player that I've owned for around 15 years. For the last 9 years I have rarely listen to my system at all, 10 minutes a year on average (no, really, no time to spare), the rest of that time it sat in standby mode. Last year I went to use my system and discovered when I went to power the up 588 on nothing happened, it was dead. As it turns out, this model uses a fairly standard switchmode PSU, but I didn't know that at the time and started looking for a replacement PSU on-line. I was finding the replacement units at a cost of around £300, and this PSU looked a lot like a PSU I had replaced in a IPTV server I have fixed at work, and that only cost £30 to replace. So I opened up my 588 and got the part number off the manufactures label and googled for that, and found the same unit from a local electronics supplier for about £35, thus saving me £265 had a bought the replacement from a Hi-Fi audio dealer. Bottom line... If something in your system does fail, do some research, find the parts on-line and if you cannot fix it yourself, find somebody competent that you trust who can. You will save a fortune in repair costs
Using a soft start circuit eliminates stress on the smoothing caps.The ones I use on my power amps and active filter are in fact very soft start types employing 470 ohms wire wound series resistors.When measuring the effects on the poweramp main caps I recorded initially 20 volts at switch on which then slowly built up to 48 volts after 3 seconds and finally 55 volts when the soft start goes out of circuit.So I would say it is unnecessary to leave equipment powered up all the time if using soft start circuitry.
All solid state, never turn it off, never had a problem, I had a Demon receiver from 2003, it's been on since day one, and now its living at my niece's house, still on. Not so much as a burned out indicator light.
I have a Jay’s Audio CDT3 mk2, and that has a Rhubidium clock which is supposed to overheat if left on 24/7. So there are exceptions to the general rule.
Well, I turn my 25 years old HK avr on and off and the receiver is still going strong. The only issue is the minor poping noise every time I turn it on because of the bad relay i guess. It is kinda annoying but can be lived with. I get around the issue by unplugging the positive banana plug on the speaker before turning the avr on and plugging it back afterward. But I understood/agree what Paul says.
Tubes have a much longer life than rumoured. I’ve rebuilt and upgraded tube gear for over 40 years and only had occasional tube problems, like shorts. I’ve never had one fail it’s transconductance testing. A better tube with low transconductance will sound better than a new one. However they use power and fortunately don’t need forever to warm up. For the sake of the 500+ volt capacitors (I’ve often replaced) turn them off after using.
Hey Paul, In my early years I used to leave my Hafler XL280 on nearly forever and still til this day it has never failed. I’ve been concerned with leaving my beastly Pass Labs class A monoblocks on at all times with the heat coming off of the sinks that run idle at 55C. The inrush limiter keeps me from having any concerns with the 132kMF cap bank being hard started. So I don’t leave the amps on day in day knowing I have the inrush limiter in the AC mains. What are your thoughts? Thank you so much for your contribution!
I am in the church that if you live in an area with dirty spike filled power or suffer frequent power outages one should cut complete power to anything not in use. Most devices these days can handle being hard powered every time. It is also a matter of all those kwh's adding up and just wasting electricity being in soft off mode doing nothing. In fact a lot of devices can get some dementia without a reboot of the firmware. I had a DVD player that never got unplugged and one day it would not let you access any controls after it started playing. Having a standby switch makes hard power switching a little safer because most of the circuit is denied power until it is turned on by its circuitry.
There's an incandescent lightbulb in a fire station in America (can't remember where sorry) that has been running constantly on for over 100 years. It's longevity is due to it running at about 30% it's full power and the fact it's never turned off and on which creates the wear that Paul is talking about. Thinking about it now they didn't say what happens during a power cut though.
Would this apply to class A amplifiers? Aside from the heat it generates and your electricity bill, would you still recommend keeping it on all the time?
Nice show . What if I live in a state like Kansas with the frequent lightning ? I also read that surge protectors fail occasionally because of the complexity of lightning so should I just leave stereo turned off if I live in Kansas ?
I use an isolation transformer based power conditioner and have left my JVC cd player on for 27 years. It's a rather expensive CD player for a JVC, $1000 when I bought it new. It sounds better when it is kept on. It sounds best when you turn off the front display lights which tells us something about power supplies.
Virtually all modern universal disc players / digital streaming devices with switching mode power supplies usually warn the owner not to turn off and then turn on the gear until more than 30 seconds have elapsed.
I agree here .... solid state stuff can and will last indefinitely ( under suitable conditions that is ) If however long periods of unuse could inspire you to shut everything down ( say you're going away on holidays for a few weeks ...) and don't want anything to go wrong while you're not around , then shutting it all down is a good idea . What Paul was saying here was that on initial switch on there are quite large peak currents demanded by the equipment . You can get round this current surge at switch on by either fitting soft start circuits ( I'm not sure if PS audio uses this ..) OR to use zero crossing switches ...Paul can explain how these work at a later time ..!!
What causes The ohm impedance in a voice coil? Is it the length of wire? Wrapped around the voice coil or the amount of turns or loops around the voice coil? Or secret option C something I'm not aware of. Like electromagnetic interference generated by both.
Humidity and heat are a major factor. Especially for items made of plastics or rubber that can become brittle faster and dry out over time if there is excessive heat from any components. If there is high humidity in the air there can be corrosion on components that can lead to electronic failure like corrosion on the pads of a relay. Really the smartest thing to do is have a climate controlled room and know what your working with. I have many amplifiers and hifi gear and in many cases there are very hot spots on the circiut boards. One example, the ART SLA1 power amplifier has a common issue (design flaw) where a resistor is burning hot and over a few years the PCB becomes darker. That whole area on the PCB has many other components that are being heated by that burning hot area. I changed mine to a much larger resistor and that resistor just gets warm now. If you look at the specs of any resistor the Celsius rating shows that it will have a much longer lifespan running cooler. The cooler the better. Excessive heat and humidity is the enemy with electronic component lifespan. Excessive heat can also cause solder joints to prematurely lift.
I had a Technics amp receiver I never turned off ever and it got very warm at 12 o'clock. It cooled back down under 9 o'clock. Back before the year 2003 with RE-30 Cerwin Vegas sounded great they were 12s maybe RE-35 I can't remember. I was probably at 200 watts cause those speakers are 4 omhs. You could hear that cheap of a system crystal clear to me back then when I walked around the block. If you decide to buy the new Cerwin Vega SL idk how good they are compared to what I had. Their party speakers crank it up and let the 100 disc play songs. Probably Tidal now, lol.
this is a good one paul. agreed. leave 'em on. :-) with a caveat though: keep the dust out(compressed air is your friend) and make sure the equipment is well ventilated.use spike mitigation protection.
My thought exactly, -I go through phases, for a while, I would listen every night before bedtime, and lately, I only power on the system in the main room a few times a month! So, in my case, I think it makes sense to power it down.
Never mind the life which is going to be say 20 years + but what about running costs? I can't help seeing dozens of your systems on around the building for what seems like 24 hours a day. What is the electricity cost per year for the building,and what is the cost and contribution of the solar panels which would have a service life of around 30 years? All that equipment must contribute to heating costs of course,however all those AC units cost a fortune to run, so what is your overall electricity bill per year?
Unless you own a piece of Bob Carver tube amp equipment like his black amps or the Cherry 180s. He put a circuit in them he calls the DC restorer which Idols the tubes so low that supposedly the last 50 years.
You understood what he meant. Right? So, why the nastiness? He was correct about the amp in the mean time. Sounds like you 'idolize' your own intellect. Which, when combined with snootiness.... loses any value it may have had.
Thanks for having a committed opinion. Makes a nice change from all the caveated could do this could do that depends on day of the week psudo advice. I suppose the downside (cue handwringing) is potentially a lot of wasted energy keeping devices in standby. But, maybe that's off set by cradle to grave analysis of energy costs of replacement for broken kit. Komplikated innit!
Same for cars... It's actually better to keep your car idling rather than another cold start. But fuel consumption concerns dictates we turn our vehicle off. Here is a tip for buying a used car.... Your best value is to buy a vehicle that is only 2-3 years old with high mileage. The price drops like a rock although the thermal cycles are same for a low mileage car. Cold starts are what actually wears on a vehicle
If you install a thermistor or other inrush current limiter on your amps, you can extend the life of your PS transformer and caps. If the amp is sufficiently sized and the PS is properly designed, this will not affect sound quality. Some circuits don't handle situations where there is a brief outage; the current limiter doesn't immediately reset. Thermal cycling may be just as important as inrush current. Materials expand and contract at different rates at different temperatures. This can cause mechanical failure of interconnects and component internals. A rule of thumb would be to turn off equipment that produces significant heat when idling. That said, I know of a tube amp that was on continuously from 1959 to 1974 with little service and no tube replacements. It was working fine when it was decommissioned. As mentioned in an earlier post, tube amps can benefit from a low voltage standby voltage on the heaters. Many tube amps have an AC heated rectifier and DC drivers. When the amp is started, it takes a while for the rectifier to "come up," thus ramping up the power to the heaters in the other tubes.
Have a 1980 technics amp. All original components. I have also had better luck with computers leaving on. I had an and 64 running Lubuntu I only turned off when it got moved a couple of times. No restarts because Lubuntu. Less heat cycling or surging. I do use surge protection plugs, but there may be less bump on switch on with 220 volts.
After vacuum tubes, the next wear-out component is electrolytic capacitors. Most owners would be shocked to learn what their predicted life is. As with most components, temperature is the main consideration for longevity, so if they run cool they will have long life, but if they're operating in a hot area of the equipment. I'd recommend keeping that equipment off when not used. Also, if you have class D amplifiers, I recommend leaving them off when not used. Many class D designs also have inrush current limiters and switch-mode power supplies with soft-start, so the turn-on surge is ameliorated.
Electrolytic capacitor life is a direct function of equipment design. They are rated for x number of hours at x % of their rated voltage and ripple current and derated as their operating environment gets harsher. I've seen equipment with 50 year old capacitors still work as intended while others will fail in under ten or even five years because the components were simply not chosen with any operating margin.
Generally speaking charging and discharging the capacitors will have no impact on them at all. Leaving them on near sources of internal heat will do far far more to the capacitors longevity. Transistors, bridge rectifiers, FET's, etc. might not like the inrush all that much. Some argument for leaving the gear on and some for turning it off. Capacitor life, they'll live longer spending most of the time cool, regardless of being on or off. It's all about the heat. Heating from Inrush current, not such an issue.
Mechanical stereo equipment is not addressed here. My experience is that turntables, cassette decks and CD players, if allowed to stand unused for extended periods, will degrade. Belt-driven turntables and cassette decks using stretched belts are especially prone to degraded performance as the belts over time can take on a set from remaining in one position for long periods of non-use. I've had this happen to my Aiwa cassette deck that sat dormant after the CD arrived. I replaced the two belts once and since then allow it to turn on whenever my equipment setup is turned on which causes the belts to be moved to a new position at each start up thus avoiding belt set-stretch. As for turntables, lubricants can harden from extended periods of dormancy. I give my direct drive-turntable a couple of drops of the correct type of synthetic oil recommended for DD motors every few years. That turntable, a Technics SL-110, is now about 40 years old and operates perfectly. My older turntable is a fifty year-old Thorens TD-124 and I have taken the motor apart twice in its life to clean and lubricate its bearings. I make it a point to use a CD player at least once or twice a week. I have two Technics units that are about 25 - 30 years old. My oldest CDs are about 30 years old and they play just fine. My custom is to leave the set-up on for most of the day when I'm at home and turn it all off at night. All of my electronic units are solid state and around 45 years old. If I were using tube equipment my habit would be to NOT leave it on for extended periods of non-use as that would probably unnecessarily shorten the life of vacuum tubes. My understanding is that a vacuum tube begins to slowly degrade from the first moment it is turned on.
I agree that snapping something on with large capacitor filter banks can cause a significant surge but leaving a large power amp on all the time is going to have a significant impact on your power bill. My amp draws 30 watts when idling because they run significant current through the outputs to keep output crossover distortion low at low levels where the amp spends most of it's time. I put a resistor between the input bridge rectifier and the power supply caps to significantly reduce the input surge. A relay closes around those resistors a couple of seconds after the amp is switched on so the resistors are not in circuit when the amp is playing music. It's a 30a relay so it has very low drop. This means you have to let the amp warm up for best performance but it reduces the surge and pisses off the electric company because I'm not drawing power 24 hours a day. It also saves wear and tear on the power switch which did not appreaciate the huge inrush surge.
IC amps - which utilize integrated circuits and op amps, also suffer from heat flexing. As chips heat up and cool off, they flex and bend themselves. Silicon is notoriously bad at it. Computer chips are especially susceptible to failure due to this. Therefore, it is highly recommended that equipment with a lot of integrated circuits be kept on. That being said, everything kept on should also be kept plugged into a good uninterruptible power supply with isolation. In most areas, line voltage is "dirty"; rife with spikes, surges, sags, and brownouts - none of which is good for your equipment.
I had my amp on all the time, and after a couple of years, a capacitor dried out, and had to be replace. Now I turn the amplifier on when I am going to use it. But I don't turn it on and off many times a day. Usually only once a day.
you are missing one huge point, by the time you pay for electricity by leaving on for 5-10-20 years you could by another amp or preamp, the same goes for hard drives in pc's. after 1-2 years of leaving on I used enough electricity to buy another hard drive!. ( now if you are talking about a $2000+ amp or preamp that might be another thing)
I can only tell you what I see all the time. Equipment that should still be in it's prime failing prematurely because some of the solid state components that are designed to run hot lose their connection to the board. The solder connections just sit and bake, causing them to fracture, and while this may or may not lead to an open circuit, the increased resistance only makes the heating problem worse. Sometimes even damaging the board to the point where the trace becomes delaminated from the board or the board itself which is supposed to be an insulator actually develops a conductive path between adjacent traces. It's really easy to see. The board turns dark in these regions. This is entirely a function of uptime, not accumulated inrush events. If you use it when you're at home and awake, use it. But leaving it on to protect the capacitors, well, I just don't get it because caps can be replaced down the road while PC boards maybe not so much.
I would say, it is better to turn them off - for energy savings, green planet etc. FOR me and MY devices. Most of the times, when I go away for the Weekend, I also pull the chords out of the wall - in case there is a storm, I do not want that Equipment to be affected. On the electrical side, Mr. Paul is right. But, I am still keeping everything off and ON onlye when I Need it. ;)
That will effectively reduce the turn-on surge to charge up supply capacitors, however it may also interfere with the operation of power sequencing circuits within the unit, if the ramp is too slow. If you do this, you should use a very quick twist of the variac control knob. For turning off, always use a switch. It's not a good idea to turn the voltage down gradually, and there is no current surge associated with switching the power off.
