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This weird trick lowers DAC distortion


mansr

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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.

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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.

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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.

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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).

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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).

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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

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Yea, cool.

 

13 hours ago, mansr said:

the THD was some 5 dB lower than the starting point.

 

Do you have a use case for this ?

 

Apologies for being serious. Speaking of that, is this the spray you used ?

 

image.png.09e013d814fbe353dbfb43a4301eae76.png

 

 

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