This weird trick lowers DAC distortion

[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 ...

[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.

[fas42]

I just had a thought about how I would do something like this - key would having a tiny evaporative coil in the system, which could be placed near the critical part. Then a small, slow running fan with the air flow funneled as precisely as necessary to what matters, say the top of the DAC chip - this would give one great control on how much cooling was going on.

 

Some of the hardware that would do something like this is inside every, discarded laptop - just run this in the reverse of the normal heat cycle.

[fas42]

5 minutes ago, mansr said:

Yes, there will be an area of lower temperature by the cold side of the Peltier element. How much lower and how far it extends depends on the thermal resistance of the various parts. To achieve any significant effect, you need to have high thermal resistance between the die and everything other than the cooling element. That isn't the case here, so cooling the chip is a bit like trying to create a vacuum in a leaky container.

 

You got impressive results when all you did was "hit it with some freezer spray" - so all you need to do is replicate that physical process by some means which can maintain it indefinitely.

[fas42]

Which is why I mentioned using some type of funneling arrangement, to organise air flow between the heat exchanger and the specific part - careful design of this should do the job.

 

I actually used this method for heat treating a graphics chip in a laptop a while ago - normal hair dryer, a crude cardboard cone between it and the part; the heat was concentrated to precisely where it was needed, for about 5 minutes - and did the job.

[fas42]

On a serious note, what one loses in technical performance by any parasitic behaviour associated with temperature rise, is more than compensated by gains elsewhere - one of the obvious ones is that power supply smoothing caps work better, because ESR drops.

 

I have to laugh every time I see these "distortion makes it sound warmer and nicer" comments - ummm, no. Truly accurate, and not the output of rigs of good measuring components, sound is "warm and analogue like". Because, that it is the actual nature of the recording.