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Amps and Preamps has standby, but should I turn them completely off?

Hi guys, I know there has been discussions of this and the overall consensus seems to be leaving the Solid State amps / preamps on (or standby). I have a Parasound A51 that runs pretty hot. The heat sinks are hot to touch after running them for 2 hours. Ever since I move them to the 2nd floor (gets hot in the summer), I worry that they'd run too hot so I turn them completely off (by switching off the surge protector) after each use. Note that standby mode doesn't solve the heat issue -- it still generates a significant amount of excess heat. 

My question is:
1. Does turning them off after each use shorten their life?
2. Does turning them off increase the probability of failure?
3. Does the excessive heat damage them in the long run by leaving them on?

I am not too worried about warm up time because I use them 2-3 times a week tops. I just don't want the excess heat on the 2nd floor since it's already much warmer than the 1st floor. 

Thanks!!
angelgz2
kijanki's avatar
kijanki
3,575 posts
 
Life of electrolytic caps is shorten by the factor of 2 for each 10degC temperature increase.  It is simply drying out of electrolyte.  Turning amplifier on often produces rush current, but heat amount from that is negligible.  Simply, your amp will last longer when you turn it off.  Also, life of semiconductors does not depend on how often you switch.  The only case I know where semiconductors are getting "tired" are big SCRs (Thyristors) in welding machines.  They go thru some structural changes caused by huge temperature gradients.  It does not apply to small current devices.  In class D amps power Mosfets are switched ON and OFF 500,000 times a second.  The only drawbacks of switching on and off is shorter life of the switch (not important with a few cycles a day) and warm-up time to get the best sound.
timlub
1,649 posts
 

Hi kijanki,

     As much as what you quote overall is true.  I have found that when large filter caps are getting old,  that switching them on and off very much affect their life span.  When they get old,  keeping them charged helps keep electrolyte from leaking and they maintain their spec very closely.  Once a cap degrades to a certain condition,  it is then that cycling them can damage them.  I hope this makes sense.  Tim

czarivey
4,494 posts
 
kijanki,
According to your statement, what is initial temperature you’re talking about to shorten by factor 2 the lifespan of electrolytic cap?
Room temperature?
Maximum rated capacitor temperature?
Zero Kelvin?
Zero Celsius?
 
P.S. You can still ask audience, eliminate 50/50, make call to friend...
almarg's avatar
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almarg
8,673 posts
 
IMO the bottom line on the many tradeoffs that are involved, which certainly figure to be dependent on the designs of the particular components as well as on the particular usage patterns, simply comes down to common sense: 

If the system is just being used a couple of days per week, as is the case here, and especially given that the system includes an amplifier that runs hot even in standby mode, as well as a hot-running preamp, turn it off on the rest of the days. 

In situations that are at or near the other extreme, where the system is used multiple times on most days, and where everything in it is cool-running, leave it on continuously. 

In circumstances that are in the middle ground between those extremes, and if the manufacturers of the particular components do not provide any  specific guidance in the manuals or otherwise, flip a coin :-).  It may not matter much either way.

Regards,
-- Al
 
czarivey
4,494 posts
 
Al,
The explained tradeofss in this thread easily compensated by owner's convenience and smaller electrical bill not only from audio power outlet, but from climate control unit as well.

If you're worried too much on healthy life and dieting as per analogy, there are also always trade-offs. I'm holding in my left hand fresh smoothie made of fresh berries and fruits not too long ago picked from farm and no sugar added; my right hand however is holding extremely tasty and sweet muffin that maybe for sure fat and having LOTs of sugar. Together it's called balance.

CHEERS!
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