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Wear and tear on amplifiers

eevo1969

pfm Member
I have a pair of class A mono blocks which obviously generate quite a bit of heat which has me wondering, which mode of operation would have the least wear and tear in the long run, turning them on and off two-three times a day/eve or leaving them on all day and evening?
Everything is turned off at the end of the day so this is just about best practice for reliability.
Thanks
 
Leaving anything at all switched on is eating up average/expected life - amplifiers, cookers, microwaves, lamps, egg-timers, it makes no odds.
 
Tough one! If you mean leaving it on 12-14 hours a day every day I reckon I'd go for the switching on and off... the min number of times... It's not clear cut though.

If mainly background music I'd get a second system or another amp.

Actually a similar dilemma led me to take my valve power amp out of the system even though I only use the main system for a few hours a week. I replaced it with... class A monoblock SS amps of my own design.
 
In my opinion heat cycling does more damage than almost any other factor so assuming decent equipment not overstressing the components I`d leave them on rather than triple the number of cycles.

Valve equipment is different, obviously, with power valves you have a finite number of hours so leaving them on unused is not smart.

Energy wastage is another issue you may like to consider.
 
In my opinion heat cycling does more damage than almost any other factor so assuming decent equipment not overstressing the components I`d leave them on rather than triple the number of cycles.

Valve equipment is different, obviously, with power valves you have a finite number of hours so leaving them on unused is not smart.

Energy wastage is another issue you may like to consider.

Exactly the same with electrolytic capacitors and vastly worse in most class A amps due to the heat. Heat being the overwhelming factor here, capacitor life in a class A amp could be a tenth of the life expectancy in a cool running amp.
 
Exactly the same with electrolytic capacitors and vastly worse in most class A amps due to the heat. Heat being the overwhelming factor here, capacitor life in a class A amp could be a tenth of the life expectancy in a cool running amp.

Agreed, which why I said assuming decent kit and not overstressing the components, i.e. not fitting the caps close to the undersized heatsink....

If the equipment has poorly specified components and construction the effects of heat cycling may well be even worse.
 
I have a pair of class A mono blocks which obviously generate quite a bit of heat which has me wondering, which mode of operation would have the least wear and tear in the long run, turning them on and off two-three times a day/eve or leaving them on all day and evening?
Everything is turned off at the end of the day so this is just about best practice for reliability.
Thanks
I'd turn them off, especially in summer, simply because of energy costs. The difference in reliability, for a sample size of 1, is not significant over the say 10 years you may own them. In terms of wear and tear it *might* make the difference between the thing needing service in 25 years as against 20. Or it might not. Will you still have it in 20-25 years' time? Will you still be around? If you were born in 1969 as per your name, I'd hope so, but even if you are will you care by then?
 
The components will have been designed and tested to be power cycled throughout their expected lifetime. If you stay within a components stated parameters for temperature, voltage etc. then you can expect the MTBF for those components and the result will be as per the expected rate of failure curve. This means that powering down will extend the lifetime.
If a component fails because of cycling then it is either defective, cheap (e.g. the promises made by the manufacturer are not real) or you have a design flaw in your amp.
 
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I tend to turn my class A integrated off ; it has some kind of ‘soft start’ anyway, which may or may not help, but mainly I turn it off to save on the bills, given that I may not use it every day anyway. In fact, I maybe use it 10hrs per week, not a whole lot more...
 
Most components fail at switch-on (IME), which suggests to me that switch on introduces stresses of its own which need to be factored in to the equation.
 
I don't consider heat cycling to be anywhere near as important.

If heat cycling is a likely route to failure then the component will have been qualified and reliability batch tested through thermal shock testing. I doubt that the thermal cycling in an amp will match the testing regimes if it's anywhere near that of a semiconductor (-65oC to 150oC, 30mins at each temp with a rapid change air to air, there's also liquid shock but it's insane and not relevent to std components). Easy to look up but can't be bothered.

Most components fail at switch-on (IME), which suggests to me that switch on introduces stresses of its own which need to be factored in to the equation.

Again, the component happily works for years until you switch on on one day and it fails. That's not the switch on, just the wear out failure mechanism causing it to give up the ghost as pretty much expected. If the switch on IS causing failures repeatedly then you have a design flaw in the amp e.g. the component is being stressed to outwith it's max parameters.

EDIT: Arkless got there before me and put it better.
 
It`s often difficult to know if the failure occurred at switch on or if it had already happened at switch off.

Probably not applicable to most amplifiers but SMPS`s have a number of components which are not important after switch on so they can fail at any time and the unit carries on working until switched off and on again.

A graphics system I used to work on, installed at a Navy base used to run perfectly for six months continuously, then the service guy would turn up, clean the fans and always at least one of the 60amp PSUs would fail to restart and have to be replaced. (They were a crap Supply, mind you - Advance)
 
I run DIY hybrid GM75 (around) 20w mono blocs - I run them once per day at most and switch off when not in use. When it’s really hot in summer I (normally, not last year) switch to a Mark Levinson No. 29. I’m still amazed that after them being in service for 15 or more years nothing has failed - the transformers run at around 50 degrees C - I have a recap on my things to do this year.
 
Thank you for the replies it really is the heat that makes me think twice about prolonged periods of use.
I’ll carry on limiting their use, maybe morning and evening only but the summer could get sticky;)
 
Can you increase airflow around them when in use? What temps do the cases get up to in summer and in use?
 
Jez, if you think this

Faulty parts tend to fail at switch on! It doesn't necessarily follow that they became faulty due to stresses caused by switching on.

why do you say this?

I'd go for the switching on and off... the min number of times... It's not clear cut though.

I turn amps off when not in use, and some amps get turned on two or three times a day. I'd assumed that it was the best policy.
 
My class A amp has the caps slightly off the base in plastic holders and are about body heat temp, the output transistors sizzle if you put a wet finger on them.

If you are wondering where the picture is ask our Apple loving dear leader why when you paste a URL of a picture in to the picture URL it doesn’t appear.


2iE7gTg
 
Having worked for a company supplying industry and Government with thousands of computer equipment the last think you want to do is switch stuff off.

Server farms have many thousands of ....well.....server computers, switches, routers etc. no one would dream of switching anything off, exactly the opposite.

Now I know I’m not talking hi fi but we are talking electronics.

If we are talking valves or Class A there maybe a heat or life expectation that you may want to consider....

If you think power consumption is a consideration and you’ve spent thousands on your hi fi you need to look at your life priorities. Does anyone switch their router off, do you go to work to charge your phone and pad?

Is the whole Internet turned off so it doesn’t fail?

Don’t start me on this green crap, get a life, the planets not ours, we are just annoying flees witnessing the planets evolution.

Volcanoes and natural planet occurring disasters will consume us eventually, why worry!

Happy to be alive.....Gary
 


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