This weird trick lowers DAC distortion

[mansr]

I was goofing around with a PCM1794A chip when the idea occurred to me to see what happened if I hit it with some freezer spray. Monitoring with the REW real-time analyser, I gave it a quick blast. The reported THD dropped a little. Another blast lowered it some more. I kept going. The chip got covered in ice crystals. At a temperature of about -25 °C (according to thermal camera), the THD was some 5 dB lower than the starting point.

 

The lesson here is clear. We need silent-running audiophile freezers with stylish looks and convenient cable inlets.

[pkane2001]

8 minutes ago, mansr said:

I was goofing around with a PCM1794A chip when the idea occurred to me to see what happened if I hit it with some freezer spray. Monitoring with the REW real-time analyser, I gave it a quick blast. The reported THD dropped a little. Another blast lowered it some more. I kept going. The chip got covered in ice crystals. At a temperature of about -25 °C (according to thermal camera), the THD was some 5 dB lower than the starting point.

 

The lesson here is clear. We need silent-running audiophile freezers with stylish looks and convenient cable inlets.

 

Here you go: https://hothardware.com/news/evga-closed-loop-liquid-nitrogen-cooling-system

 

[Archimago]

26 minutes ago, pkane2001 said:

 

Here you go: https://hothardware.com/news/evga-closed-loop-liquid-nitrogen-cooling-system

 

 

Nice. Is the circulation system absolutely silent? We might get another -5dB THD but wouldn't want the ambient SPL in our room going up, right? 😉

 

[fas42]

Amazing ... temperature differences make a difference - who would have thunk it? Those villainous circuit designers should be shot, for not getting this under control ...

[pkane2001]

51 minutes ago, Archimago said:

 

Nice. Is the circulation system absolutely silent? We might get another -5dB THD but wouldn't want the ambient SPL in our room going up, right? 😉

 

 

You can set the desired temperature, say -75C! Condensation may become a problem, though.

 

 

[esldude]

I ran across this somewhere else at one time.  My suggestion was to put a peltier like people use on overclocked CPU's onto the DAC chip.  Should do the trick silently if not in an energy efficient manner. 

[AudioDoctor]

57 minutes ago, Archimago said:

 

Nice. Is the circulation system absolutely silent? We might get another -5dB THD but wouldn't want the ambient SPL in our room going up, right? 😉

 

put the noisy bits outside the room and just pipe the coolant in. 

[pkane2001]

7 minutes ago, esldude said:

I ran across this somewhere else at one time.  My suggestion was to put a peltier like people use on overclocked CPU's onto the DAC chip.  Should do the trick silently if not in an energy efficient manner. 

 

Still requires a radiator and a fan. In amateur astronomy, peltier-cooled CCD chips are a must to reduce noise during a long exposure. The better ones use nitrogen-filled electronics compartment to prevent condensation. Some do use water cooling to remove heat from the hot side of the peltier. Professional cameras usually use liquid nitrogen.

[mansr]

30 minutes ago, esldude said:

I ran across this somewhere else at one time.  My suggestion was to put a peltier like people use on overclocked CPU's onto the DAC chip.  Should do the trick silently if not in an energy efficient manner. 

I tried that, but I couldn't easily cool the hot side sufficiently.

[PeterSt]

From close to the past year of "development" (and public forum posts about it) I by now have the proof the other way around: heating up the lot by means of break-in which can be repeated each and every day, deteriorate THD.

 

Heat-up: not measurable by thermal measurement (unless by means of whatever behind the decimal point).

 

Break-in: Just keep the lost under normal playback means and constraint / strength (mimic impedance is tough without sound).

 

So all 'n all, software-wise I have created a repeatable situation (measured on a per day term) that keeping all under the tension of 24/7 payback, deteriorates sound.

The other way around seems obvious indeed. But for me a long shot because e.g. heating up the lot with a föhn, surely does not speed up real breaking-in.

 

17 minutes ago, pkane2001 said:

peltier-cooled CCD chips are a must to reduce noise during a long exposure.

 

I have all that stuff laying around and will apply that to the D/A chips readily tomorrow now.

 

FYI (again): I have been testing with this idiocy for almost a year by now (software incurred). So it is high time to apply the opposite.

 

Funny thing is that this afternoon I was discussing the invention of the Warmth Wheel and mentioned Peltier and how it works. Time to have a real application for the latter. Or at least a test of it for the better SQ.

[PeterSt]

10 minutes ago, mansr said:

I tried that, but I couldn't easily cool the hot side sufficiently.

 

Same here. Worked for weeks on it. We may well say that the efficiency of it is too low. Also, ambient "leaks". It requires thermal isolation beyond normal means.

A bit hard to explain, but I think you will understand what I mean.

[mansr]

3 minutes ago, PeterSt said:

Heat-up: not measurable by thermal measurement (unless by means of whatever behind the decimal point).

Huh?

[PeterSt]

25 minutes ago, mansr said:

Huh?

 

Try it. With really low TDP (like measuring 25C or so at the chip's surface) continuous operation on any of the chips, no continuous use would show a higher temperature. Still, running that for 24/7 will degrade THD by the ever so slightest means (like 0.002dB or so). This is audible like crazy (perhaps because of means beyond my knowledge).

 

You applied it the other way around: cool the chips to a relevant degree, and measure a sheer 5dB of less THD. I believe you without checking.

 

Btw, 5dB is rather much, but easy to accomplish by this aggressive means (like a heat source would do it the other way around I guess).

 

So yes, it is the way to go. I am quite confident of that.

[pkane2001]

15 minutes ago, PeterSt said:

From close to the past year of "development" (and public forum posts about it) I by now have the proof the other way around: heating up the lot by means of break-in which can be repeated each and every day, deteriorate THD.

 

Heat-up: not measurable by thermal measurement (unless by means of whatever behind the decimal point).

 

Break-in: Just keep the lost under normal playback means and constraint / strength (mimic impedance is tough without sound).

 

So all 'n all, software-wise I have created a repeatable situation (measured on a per day term) that keeping all under the tension of 24/7 payback, deteriorates sound.

The other way around seems obvious indeed. But for me a long shot because e.g. heating up the lot with a föhn, surely does not speed up real breaking-in.

 

 

I have all that stuff laying around and will apply that to the D/A chips readily tomorrow now.

 

FYI (again): I have been testing with this idiocy for almost a year by now (software incurred). So it is high time to apply the opposite.

 

Funny thing is that this afternoon I was discussing the invention of the Warmth Wheel and mentioned Peltier and how it works. Time to have a real application for the latter. Or at least a test of it for the better SQ.

Report the results, Peter! 

[PeterSt]

Btw, don't underestimate other sources of influence because of heat.

Of course it depends completely on the design. But for example, the DC Offset measured at a DAC output is always subject to heat somewhere along the chain (within the D/A process, including the gain stage).

 

DC Offset also applies to a differential setup, where it manifests in THD aggressively (plus and minus are influenced differently). So this is now now expressed in THD per D/A element (like a mono channel chip) but to the net result (plus and minus fighting).

[pkane2001]

26 minutes ago, mansr said:

I tried that, but I couldn't easily cool the hot side sufficiently.

run a water cooler to remove the heat, then run the water through a bucket full of water and ice  add some alcohol to the water to stop it from freezing. Believe it or not, that works for quite a while.

[PeterSt]

3 minutes ago, pkane2001 said:

Report the results, Peter! 

 

You bet. But I'll start with sound quality. I am really used by the other way around by now. So yesterday I deliberately did not start this software process (of the next 24 hour implying playback). Sound is really more "relaxed" because of this. This, while I know for 5-6 years by now that in my specific situation, playback needs to commence for ~20 minutes to develop a balanced sounding operation.

With the 24/7 thing this indeed lacks (no difference audible for whatever next minutes of inital playback). But doing nothing (the past 24/7) is also not good (again, in the situation I have at hand here). So it is all quite sensitive.

 

The Peltier solution can be tuned to the most sensitive temperature setting with resistors (I did not try, but is should work).

[PeterSt]

6 minutes ago, pkane2001 said:

Believe it or not, that works for quite a while.

 

Yes. But not forever.

[pkane2001]

1 minute ago, PeterSt said:

 

Yes. But not forever.

works as long as you add fresh ice to the bucket

[PeterSt]

true

[PeterSt]

I wish I made photographs of all the (very low voltage) fan means I applied to the cooling part. So the Peltier element would cool itself. It always worked ... 

... temporarily.

 

Next up :
perpetuum mobile

[fas42]

24 minutes ago, PeterSt said:

 

You bet. But I'll start with sound quality. I am really used by the other way around by now. So yesterday I deliberately did not start this software process (of the next 24 hour implying playback). Sound is really more "relaxed" because of this. This, while I know for 5-6 years by now that in my specific situation, playback needs to commence for ~20 minutes to develop a balanced sounding operation.

With the 24/7 thing this indeed lacks (no difference audible for whatever next minutes of inital playback). But doing nothing (the past 24/7) is also not good (again, in the situation I have at hand here). So it is all quite sensitive.

 

The Peltier solution can be tuned to the most sensitive temperature setting with resistors (I did not try, but is should work).

 

There is no such thing as a "this is the way it always goes", but I have never found very long term switch-on to be a problem. Unless there is some issue with static build-up, somewhere in the chain - switching off, and then back on again after the power supplies discharge is a way of identifying this sort of anomaly.

 

The normal cycle is reasonable sound on switch on, which gets more detailed, and somewhat uglier for an hour or so, to finally "smooth out" after that - detail and finesse, both working.

 

Humidity helps - a hot, dry day usually means a lower standard, as a rule of thumb.

[AudioDoctor]

DAC makers hate this one simple trick...

[gmgraves]

4 hours ago, pkane2001 said:

 

Here you go: https://hothardware.com/news/evga-closed-loop-liquid-nitrogen-cooling-system

 

I don’t doubt it, as a former semiconductor engineer, I have seen experiments where microprocessors were subjected to cryogenic temperatures. They always ran faster, and more efficiently, the colder the chips became. In all the experiments to which I was savvy, the cold was applied to the bare die, not to the encapsulated IC. While a cooling system using a refrigerant is somewhat impractical, we could use one of those semiconductor “heat pumps”, the kind used in portable electric coolers, and which are cold on one side and hot on the other. I don’t believe that it would work unless the cold side of the semiconductor heat pump were in direct contact with the DAC die. 

[4est]

This experiment doesn't seem all that unusual from what one might expect. I'd like to hear the results about the same thing done with the clock being frozen instead of the DAC chip.