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Do you leave your DAC powered on all the time?


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On 19.04.2017 at 6:41 AM, wgscott said:

I was reading about this in another thread, and I didn't want to hijack it any more than had already been done, so I'm starting this one.

 

I'm in the habit of turning everything off but my computer (which stays on all the time for a variety of reasons).  

 

My DAC (a TEAC NT-503) has an auto-off feature (that can be turned off) that turns it off if idle for more than 20 minutes (the only time-out option).  Because of this, I just assumed there is no harm in turning stuff off, and my midwestern puritanical upbringing is such that I hate leaving stuff turned on, especially when I am not at home.

 

On some occasions where the DAC/amp have been left on overnight, I have never heard any obvious difference or improvement, but then again I wasn't expecting to, and wasn't listening for it.

 

So, is this good practice, or audiphoolry?

 

1. From point of view safety of device, I don't know what variant better: switching decrease life time. But long warm mode may wearout capacitors. Other hand, life time of the capacitors is big anyway.

2. From point of view sound. Audio device must come to work mode after several time. In manuals I seen such recomendations. Probably device adjusted in such mode on its factory. But I don't notice any difference there.

 

3. From point of view fire safety recommended turn off devices. But there need fully turn off energy.

 

4. From point of view electro energy saving recommended turn off too. Though DAC have no big consuming.

 

If consider these things in complex, I think, turning off is better choise.

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I do notice that my Oppo 103d with audiopraise vanity module will experience drop outs when first powered up and connected to my DAC. 

 

I find that that if I turn it on and leave it on for awhile, then quickly turn it off and on again, the drop outs stop... 

 

 

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I turn everything off at the wall - a power strip with one big button - when not in use, and it made a huge difference to the electric bill. An exception being the Mac which goes to sleep, and wakes on network access. Before listening, I try to give things 30 mins or so to warm up (for clocks to stabilise, etc). Class A amps are just too power hungry to be left doing nothing (but warming the living room) for days at a time. As for femto clocks, they'll get over it.

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5 hours ago, Ralf11 said:

my understanding is that is [a] cloned or rewritten, and has the nice GUI shell

 

maybe I am not grepping the question?

 

just ideas as to why OSX may not have the same uptime duration as a VAX or something running Berkeley etc. 

 

Jordan Hubbard, Mike Smith, and Terry (sorry, forget his last name), FreeBSD (BSD standing for Berkeley Software Distribution) project leader and kernel hackers, respectively, hired by Apple to work on OS X in its relatively early days, might be surprised to see it differentiated from "something running Berkeley."  The "nice GUI shell" is different, yep.

 

Edit: Terry Lambert

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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Sorry if I was unclear.  Apple paid for certification, via The Open Group, with Leopard IIRC.

 

My point is whether OSX has anything in it besides AT&T code or BSD code, that could cause greater system instability with longer intervals between reboots.  Besides the GUI shell, userland programs could be culprits.

 

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My nuc and dac stay on all of the time. Amp gets turned off when not in use.

(1) holo audio red (hqp naa) > chord dave > luxman cl-38uc/mq-88uc > kef reference 1
(2) simaudio moon mind 2 > chord qutest > luxman sq-n150 > monitor audio gold gx100
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  • 2 weeks later...

I did some measures of warming up gear from cold today.

 

I started both an ADC and DAC from a dead cold start.  Ran some measurements immediately and then at 35 minutes, 63 minutes, and 114 minutes later.

 

The first surprise is timing and jitter.  Cold while I have no way to measure absolute clock speed, the clock rate difference between ADC and DAC was 81 ppm.  At 35 minutes it was 79 ppm and stayed at that speed. Using a quarter sample rate tone the sharpness of the tone and observable jitter sidebands changed not at all even dead cold compared to 114 minutes later.  I may post graphs of those later on.

 

The noise floor did drop nearly 5 db from cold to 114 minutes later. I guess analog circuits care more about warmup!

 

The 3rd harmonic of a 1 khz tone was -97 db cold, - 99.5 db at 35 minutes, 99.7 db at 63 minutes and 99.9 after 114 minutes.

 

The 1 khz difference with a max level 18 khz and 19 khz tone for testing IMD was -112.5 db cold, -114.5 db at 35 minutes, -115.4 db at 63 minutes and -115.9 db at 114 minutes. 

 

So it looks like analog circuitry benefits from some warm up at least for two hours.  Though the differences are not at all likely audible.  The big surprise is timing and jitter change very little and apparently stabilize quickly or at least less than 30 minutes time.

 

So my suggestion would be turn your DACs off.  No need to leave them on forever.  One less thing to obsess over.

 

 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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From my experience in the studio there are audible differences in gear warm vs cold. Recordings with tube microphones sound a lot different cold vs warm, thus nobody records cold and they were never meant to be used cold. With studio clocks using OCXOs the difference is also quite audible. Having said that, the warmup process does not take ages, about half an hour for the tube gear and 15 mins for OCXOs. Maybe add a few minutes to be on the safe side, everything beyond that is snake oil. Leaving stuff on 24/7 will just add to your carbon footprint and wear down your gear more quickly; the lifespan of caps even today is limited and very much depends on temperature. 

 

Add your tiny contribution to save the planet and switch your gear off!

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19 hours ago, esldude said:

So it looks like analog circuitry benefits from some warm up at least for two hours.  Though the differences are not at all likely audible.  The big surprise is timing and jitter change very little and apparently stabilize quickly or at least less than 30 minutes time.

 

Thank you so much for the measurements. I used to leave all my system on those days. That also including a 350W on standby power Amp. 

 

Adter about a year, I stopped the practice and only turn on the Amp two hours before listening. Only the Amp made the difference with the two hours warm up time. The DAC did not make any difference.  

 

Now, it is usually about 10 minutes, including the ESL speakers which I think the highs improve after about 30 minutes. But then, I usually play softly the at first before blasting it away. 

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Thx for those measurements - I agree the SQ differences are likely nil

 

We still need someone to do a listening test with 2 identical components - one warmed up & one cold

 

for those concerned with wasting energy, turning a DAC (or any other wall-wart powered component) off at the front panel saves nearly nil energy as the wall wart is still powered - you'd be best served by putting all the wall warts on a power strip and turning that off

 

- unplug it for lightning protection

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My experience has been that while I tend to shut everything off when not in use, it does seem to take 10 minutes or so to warm up enough that things will not change much after that. There is a difference between just turned on, and after even this somewhat brief warm-up period, but two hours later or even all day later things are about the same.

 

I have done some load testing and have determined that when everything is turned on the current draw is quite high, higher than I would have expected so I do try to be power frugal and turn the systems off when not in use.

 

The DAC though draws the least amount of power of anything in the system and while it too can shut itself down after inactivity, then it won't work if I want it to and have not remembered to turn it back on, so inconvenient. And the DAC seems to be the device that benefits from warm-up the most although this is just my assumption. 

 

As to power surges versus steady-state power use ... I leave a PC server and a couple of NAS boxes running all the time. The NAS boxes actually draw surprisingly little power and are engineered to be on 24/7 so I go with that and have had pretty good results. The PC draws more power but is very useful doing all manner of things so I tolerate it being on all the time. My first server ran (Win2000) non-stop for almost 11 years before being replaced with the current machine which I hope will do the same. No sleeping allowed ....

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I said I would post some graphs of jitter levels in my prior post.  I listed differences between warmup and 2 hrs of operation which mostly looked to be in the analog circuitry.  I expected clocks would be picky about settling down.  There was a minor change in clock rates over the first half hour.  I was surprised the quarter sample rate tone which will make some types of jitter visible showed no change between cold and 2 hrs later.

 

First is a 128K FFT of that tone covering 10 khz to 14 khz with the frequency of the tone centered on 12 khz. There are a couple spurs one at 300 hz above and below the tone, and one that fluctuates 392 hz above and below the tone.  Red is give or take a few seconds 2 minutes after turn on.  Green is two hrs after turn on (actually 114 minutes).

 

  5906fdbc8b663_Jitter2keachway.thumb.png.48f4f671a9176222d0e50b84a49cbd5a.png

 

Here is a view close in that covers 12 khz plus or minus 50 hz.  A fairly good result.  10 hz away from the central tone the level is already down to about -100 db.  It is -80 db down at only 2.5 hz either side of the tone. Again red is cold and green nearly 2 hrs later.

 

5906fe4aaeee9_jitter50eachway.thumb.png.a1eabd9e64d0a782cf5c3bb9c55b08df.png

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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To give an idea of what the last FFTs are showing here is one with red being the previous gear used for the warm up testing.  The green is all the same gear except a different DAC.  It has tighter control near the center of the 12 khz tone with less spreading at the base, but it has numerous spikes either side of it.  Though low in level they would be signal correlated.  First is the 4 khz wide view and then the close in 100 hz wide view.

 

59070274b93bc_jitter2keachwayalternate.thumb.png.63cd390f4a035774675cf819359bd950.png

 

 

5907028b4c528_jitter50eachwayalternate.thumb.png.94cee8bc18a7297b0741998c7198c680.png

 

 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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30 minutes ago, STC said:

ESLDude, perhaps you could add the sound sample and let us hear the difference itself. Hearing is believing. :)

 

Like that has ever done anything other than cause arguments here on CA. :ph34r:

 

So are you wanting samples of the two different DACs (which actually I have already done in the past)?  Or the sound of cold vs 2 hours later?

 

Maybe I could do this one differently.  Post the two DACs, tell you which is which, and chances are few have heard either much less both.  Then people could describe the differences they hear.  In addition I could post a cold file and one 24 hours later for each and we could describe which one warmed up better.  B|

 

 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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2 minutes ago, Ralf11 said:

label one A, the other B

 

Let people guess which is which - see what happens

Perhaps you missed when I posted two identical files and a copy of those.  Only to have people argue the two identical files sounded dramatically different.  One of them sounding much like the copy.  One not at all. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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