Amp always on?

amplifiers, receivers and loudspeakers
Solist
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Amp always on?

Post by Solist » 10 Jun 2019 21:18

I am looking for opinions about this.

I have read that its best to keep the amp constantly powered. I have been practicing this for a while now. If I am planning to spend the whole day in the apartment I keep it powered. At night I turn it off since its 50 years of age. If I have time only for 1 record, I rather not turn it on at all. Worth mentioning that the amp runs cool even after being on for 12 hours, not much watts to heat things up (30w).

georgesgiralt
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Re: Amp always on?

Post by georgesgiralt » 11 Jun 2019 06:39

Hello Solist,
It depend on the technology : Tubes have a limited lifespan due to the cathode emission. When they are hot, the cathode emits electrons and wears out. Slower if not working but wears out, nonetheless.
On the other hand, solid state electronics suffer from spikes created at power on and power off. There is a failure mode for this. So it could make sense to let them switched on. But, if your amplifier is Class A, it will eat it's max power even without signal. Is it wise to use all that power for nothing at all ? You decide, but I won't do it for myself and accept the fate if something wrong arose.

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Re: Amp always on?

Post by aardvarkash10 » 11 Jun 2019 07:49

the only reason for leaving an electronic device on is so it is "warm" and you don't get condensation forming on cold components.

If your apartment is dry and warm, stop wasting electricity by leaving the amp turned on. You are not achieving anything.

Alternatively, if you live in a cold damp apartment with mold growing on the furniture and no need for a fridge, leave the amp powered up.

georgesgiralt
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Re: Amp always on?

Post by georgesgiralt » 11 Jun 2019 08:54

Well, such an environment is not safe to humans either, so the amp status and longevity is of lesser importance ...

Pauw
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Re: Amp always on?

Post by Pauw » 11 Jun 2019 09:53

Save the planet.....turn it off. :D

Solist
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Re: Amp always on?

Post by Solist » 11 Jun 2019 11:04

Should mention its a solid state. If I switch it off after only 1 or 2 records there is a rather loud pop when I hit the power off. If I leave it on for a couple of hours, that pop does not happen.

I dont think its class A, it might be, the heatsinks are large enough to dissipate that 30w without getting things hot. In regard to saving the planet, I compensate with using the bike instead of a car. But then I tend to drink a lot of water, and I end up hitting the toilet more often, which means even more water gets wasted =P~

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Re: Amp always on?

Post by simonineaston » 11 Jun 2019 13:32

Graham Slee is adamant that his products sound better, always-on. Me, I can't hear the difference!

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Re: Amp always on?

Post by georgesgiralt » 11 Jun 2019 13:35

Have you tried to turn the volume down before turning the thing off ? Sometimes it reduces the pop. Also try to select a non sensitive input source (switch from phono to AUX or Tuner... ).
It is easy to test for the consumption of the device while sitting on stanby : Either use a milliamp and measure the current consumed by the amplifier while playing loud music and make the same measurement while sitting still. (use an analog meter because if the current varies a lot, eyeballing the average value is easy with a needle but not so with a flickering display).
Another solution is to measure the power used with those smart plugs you put between the device to test and the wall plug. They can give you the exact watts used and even calculate the cost if you entered the kWh value in the computer ... In Europe one can find them quite cheap in DiY stores or Eco friendly stores.
If using such a device, play your amp for a couple of hours and look at the watts used, then let it idle for the same amount of time and look at the watts used...
If it is a vintage amp (or a vintage schematic based amp), chances are it is a class A or AB. On solid state, pure class A is not so common.

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Re: Amp always on?

Post by georgesgiralt » 11 Jun 2019 13:41

simonineaston wrote:
11 Jun 2019 13:32
Graham Slee is adamant that his products sound better, always-on. Me, I can't hear the difference!
Yes, there is a theory that the caps in the power supply take ages to reach the PS voltage. It is quite true but irrelevant. The caps charge and tend to reach the charging voltage (if they are perfect/good *) as they "tend" the physicist or the mathematician will tell you they never will reach the value which is the limit... So letting them charge for days or for a couple of seconds before putting the amp to use is of no consequence. But the above statement will impress the less scientist of our flock...

*: if they are leaky, they will reach a voltage equal to the PS voltage minus a percentage of this PS voltage function of the leak. If the amplifier did not serve for a very long time it is good practice to awake the caps by using a Variac at the first power on to apply a slowly increasing voltage to them (but they are often dead anyway)

Solist
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Re: Amp always on?

Post by Solist » 11 Jun 2019 14:29

I do hear a slight improvement after I play a couple of records. It might also be a psychological thing.

Just recently, I powered the amp back on, after a 2 month hiatus, and the difference there was big. I asked a skilled technician once, if it would be wise to change at least the electrolytic caps, but he told me than its best to keep it like it is. Components aging together is usually better than replace it with a fresh cap. I know its a hot topic, but that was his opinion on it.

I also like to warm it up before going crazy with the volume knob.

Thank you for the suggestions! Will try to do as suggested. I am using a separate phono stage, and I always turn the volume to 0 before switching it off and wait a couple of minutes.

H. callahan
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Re: Amp always on?

Post by H. callahan » 11 Jun 2019 16:56

Its a double-edged topic.

On the one hand electronic parts like capacitors for example do age faster when they are warm so keeping an amp on all the time isn´t good for lifespan.

On the other hand some electronic parts work best at a certain temperature - or at least did because i once read that recording studios left on their amps/mixing consoles or whatever all day and night to get best sound quality possible. I don´t know why and whether it was for tube- or transistor-equipment but there at least was a reason - and recording studios try to go for best sound quality and a mixing console can have a lot of electronics inside, so degradation of sound is more likely than with a home-use amp.


Now i have made an observation with my own amp, its from the 80s all transistor, japanese making, so electronics should be pretty high grade. It has a relay which will connect through a few seconds after i hit the power-button. The manual says it only will connect through when there is no electrical problem with the amplifying circuits, like misconnected speakers for example. So this amp has some sort of safety-feature and the amplifying circuits only will be connected when there is no electrical problem which might dammage the amplifying circuits.
The problem is that my manual only does say "electrical problems like misconnected speakers", but it does not say at what other problems the relay won´t interconnet.
And sometimes the relay refused to interconnect, though nothing had changed. So i replaced the relay, it did improve sound and it did interconnect more often but still it sometimes just refuses.

Now i have found out that the relay refuses to interconnect when relative humidity is above 50% - also i have found out that there is a film capacitor in the power-supply-circuit and film capacitors can become leaky with age. When they are leaky humidity can go into the film capacitor and reduce its capacitance and this probably is why the relay of my amp does refuse to interconnect when humidity is above 50%.
Now i´m planning to replace it but i have found an interim solution:

Because when i switch on the amp and the relay does not interconnect, there still will electricity be going through the power-circuit warming up the film capacitor. So by leaving the amp on for about 20 minutes, the leaky film capacitor will warm up, dissipate the humidity it has accumulated and when i then switch the amp off and again on, the relay will interconnect because now the amplifying circuit can be supplied with the correct electricity as the film capacitor of the power supply has regained its capacitance by drying.
...

So it is possible that your impression of your amp sounding better when being warmed up can be correct - you could research what kind of capacitors ect. there are in your amp and if those can become or are prone to humidity.

Also you could observe if the performance of your amp is dependend on humidity.

But especially because your amp is 50 years old i would not run it longer than necessary, green planet left aside, and if some electrical components have become prone to humidity i´d replace them as they might be close to death. And if your amp does not have some kind of safety-relay you could suffer severe damage, respectively you won´t have to heat-up the amp that long anymore which would reduce "wear" on the other electrical parts.

Solist
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Re: Amp always on?

Post by Solist » 11 Jun 2019 17:50

Here is the patient:

https://www.hifiengine.com/manual_libra ... v-80.shtml

So that pop might be a part that on short listening sessions does not warm up completely, causing the pop through the speakers? I am a complete novice when it comes to amps, but would like to keep this one going for as long as possible. Worth also mentioning that when I turn the amp off there is still current going to the speakers for about 6 seconds. No idea if this is how its supposed to work or not.

The resistors are carbon, and I have no idea how it was previously stored since I bought it online.

georgesgiralt
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Re: Amp always on?

Post by georgesgiralt » 11 Jun 2019 21:33

This behaviour is normal. The power caps are fully charged and it may take up to 10 sec to discharge them fully. This time, the power flows to the amplifier... So you can hear sound into the speakers until the caps are depleted.

markcass
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Re: Amp always on?

Post by markcass » 11 Jun 2019 22:22

Hi

I used to keep the amp switched on when I ran a Rotel 820BX2, but it was bought second-hand in the 80s, when "always on" was the Linn/Naim mantra and was widely recommended by hi fi 'sages'.

More recently, I have always put my amp into standby, when available, or just switched it off. I feel this has some advantages in terms of longevity and, perhaps, safety. I haven't noticed any downside.

The Rotel amp never gave any trouble BTW, in spite of being left switched on. It was still working when I gave it to someone whose own amp had failed.

HTH

Mark

Solist
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Re: Amp always on?

Post by Solist » 11 Jun 2019 22:48

Thank you for taking the time to anwser my questions. Much appreciated!

I will try and let it run for shorter periods of time. Are there any symptoms that would indicate something is going wrong? The technician told me, that if the sound is still clear at low volumes, and if there is no distortion when turning the volume up rapidly the amp should still be fine.

I know that the only way to know for sure is to check every single part, but currently I cant afford a full check service. And Id rather not poke inside, since I lack the necessary skills.

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