Topping D70s MQA Review (DAC)

[Doodski]

OK @Nick5 I read the web pages on reforming. What's next?

 

[pseudoid]

What's next?

To link your Q back to previous sub-topic; I would say, we all gonna take a hit when they impose electron tax on 'us'.

 

[Nick5]

OK @Nick5 I read the web pages on reforming. What's next?

Okay so here the kicker, what if the reforming of the caps over extended period of time in the d70s (or any other DAC) could be the reason behind the change in sound quality during the initial 200-300 hours? My hunch is that the caps when new do not show their full potential, meaning higher THD/Noise initially and then tapers down to lower figure after complete reforming of the caps (if there’s such a thing as 100% reforming). So when new the caps exhibit lower CV which is restored over time and after full reform. Ideas/comment ??

 

[Nick5]

We don’t know the age of the caps in our equipment at the time of purchase. Some could’ve been in storage for a long time before soldering into the equipment in addition to the time the equipment is stored before being sold to us which all necessitate reforming process.

 

[Nick5]

It would be nice to perform measurement analysis using the above “theory” on a new D70s with zero hours and retest again after 200-300 hours….

 

[Doodski]

Okay so here the kicker, what if the reforming of the caps over extended period of time in the d70s (or any other DAC) could be the reason behind the change in sound quality during the initial 200-300 hours? My hunch is that the caps when new do not show their full potential, meaning higher THD/Noise initially and then tapers down to lower figure after complete reforming of the caps (if there’s such a thing as 100% reforming). So when new the caps exhibit lower CV which is restored over time and after full reform. Ideas/comment ??

The electrolytic caps tolerance/capacitance per unit volume (CV) before and after the proposed reforming vary so much that I'm not even sure the DAC electronics would operate if before reforming the tolerance was way way off. Of course if a total capacitor failure there will be a serious issue but we are apparently concerned hypothetically with CV variations and not total failures. Then there is the topography of the specific circuits like filtering/shunting of unwanted energy and DC decoupling/AC coupling and so again is the capacitor value uber critical in all these topographies? I say no. I notice that in some DAC circuitry they use non-electrolytic caps to avoid all the disadvantages of electrolytic caps. I think those non-electrolytic caps are in the signal path and so reforming is not possible in that specific situation. Otherwise I would really appreciate seeing a good long burn-in test too. The resolution of the tests would need to be very fine due to the specific nature of the test(s) and the subtle changes expected. A good'n tidy burn in test of DACs and speakers would answer many questions that come up here at ASR time and time again. As @amirm has emphasized the tests are oriented to testing the entire device/DAC/component and not just sections of the circuitry. If there is a change it must be measured with the device as a whole and not specific sections like external power supplies or other external MODs and tweaks. So with that in mind if the test from input to output results in a noticeable change then the test is complete for ASR.

 

[Doodski]

and... there are issues concerning measuring to such fine resolution. The temperature could throw off the results or any other changes in the environment.

 

[Raindog123]

@Nick5 Do you listen a DC signal through your D70s? Because that’s what would be required to “reform” it…

 

[Rottmannash]

Why do you assume I’m upset? I’m having lots of fun.

But are you contributing anything worthwhile to the discussion?

 

[Nick5]

@Nick5 Do you listen a DC signal through your D70s? To “reform” it?

funny but you have a point. Unfortunately I don’t hear a thing at DC. Imagine if I did then our friends on the other side of the fence would shoot us .
When I purchase a new HiFi equipment (or build one) that contains elec. caps in its PS, I usually leave it running 24/7 for up to 200 hours with occasional critical listening to get a feel on the changes in sound quality. Really simple and 200+/- hours should be adequate to reform the cap in my opinion. You know it when the sound reaches its optimal state without further improvement. YMMV.

 

[Nick5]

But are you contributing anything worthwhile to the discussion?

Yes. The D70s is an awesome piece of equipment and will sound marvellous after it has accumulated 200-250 hours of continuous running. Initially I was considering buying the TOTL Denafrips but glad I didn’t. The D70s is hard to beat.

 

[Raindog123]

When I purchase a new HiFi equipment (or build one) that contains elec. caps in its PS, I usually leave it running 24/7 for up to 200 hours with occasional critical listening to get a feel on the changes in sound quality. Really simple and 200+/- hours should be adequate to reform the cap in my opinion. You know it when the sound reaches its optimal state without further improvement.

Thanks. I’ll pass it to our flight control guys. Suggest for them to wait, what, 200-300 hours before performing an ISS autonomous precision docking, or first-stage booster precision landing. To let all those capacitors to settle, reform, and all that…

Seriously, as it has been pointed out by many. Yes, there is certainly a drift of capacitance, resistance, gain of electronic components. (And temperature dependence is usually the main reason.) However, all this is well known and accounted for in the circuit design - eg, of amplifier gains, filter bands, etc - through feedbacks, comparators, control loops, etc. So, the result is "drift tolerant by design”.

 

[Nick5]

Thanks. I’ll pass it to our flight control guys. Suggest for them to wait, what, 200-300 hours before performing an ISS autonomous precision docking, or first-stage booster precision landing. To let all those capacitors to settle, reform, and all that…

Note that we’re discussing the impact on SQ and not functionality of the equipment.

Seriously, as it has been pointed out by many. Yes, there is certainly a drift of capacitance, resistance, gain of electronic components. (And temperature dependence is usually the main reason.) However, all this is well known and accounted for in the circuit design - eg, of amplifier gains, filter bands, etc - through feedbacks, comparators, control loops, etc. So, the result is "drift tolerant by design”.

True but we’re all attesting to the minute variation in electrical behaviour of equipment over time. Some “gifted” people are able to correlate that to changes in SQ. Nothing wrong with that. The fact that we let our precious test instruments to stabilize prior to taking accurate measurements is a good proof that electrical properties change with time which could impact SQ in the case of a DAC or any HiFi equipment.
I don’t want to dwell on this but maybe we should start a new thread and ask members to vote if they’re able to identify changes in SQ during the initial 200 hours. We can take the D70s as the subject of our vote. Although it’s system dependant, I’m also curious to find outbthe split between those who are able and unable to distinguish.

 

[Doodski]

maybe we should start a new thread and ask members to vote if they’re able to identify changes in SQ during the initial 200 hours. We can take the D70s as the subject of our vote. Although it’s system dependant, I’m also curious to find outbthe split between those who are able and unable to distinguish.

I don't think I have the "hearing memory" for this kind of test. It's very short term.

 

[caught gesture]

Note that we’re discussing the impact on SQ and not functionality of the equipment.


True but we’re all attesting to the minute variation in electrical behaviour of equipment over time. Some “gifted” people are able to correlate that to changes in SQ. Nothing wrong with that. The fact that we let our precious test instruments to stabilize prior to taking accurate measurements is a good proof that electrical properties change with time which could impact SQ in the case of a DAC or any HiFi equipment.
I don’t want to dwell on this but maybe we should start a new thread and ask members to vote if they’re able to identify changes in SQ during the initial 200 hours. We can take the D70s as the subject of our vote. Although it’s system dependant, I’m also curious to find outbthe split between those who are able and unable to distinguish.

I find that moving my head slightly in the sweet spot changes the sound. It would be nigh impossible to do any sort of listening test that you could reliably use as proof of anything as there would be too many variables that could also influence perceived changes (not withstanding the aspect of expectation bias). I say just enjoy the music!

 

[304290]

Playing the devils advocate, what parts of the story do measurements fail to tell?

I have seen a few reviews here where a piece of gear tests well but doesn't get a a good subjective review and isn't recommended.

I don't know what all the answers are here in this objective/subjective debate other than to say that if subjectivity wasn't a factor why would subjective opinions be included audio science review?

Not trying to single you out my friend, just picked your post (lucky you lol) to respond to as it seemed to dovetail into my opening question.

I should have been more clear about measurments not telling the whole story. I meant overall, not strictly sonics.

Features, build quality etc. For example, I love the features of the d70s. I also like the build quality of it. I had the su9, and returned it for various reasons. Though with the correct firmware, they may measure really close, and I doubt I could discern the difference sonically between either. The build quality and feature set of the d70s puts it over the top for me.

That's a clear case of measurements not telling the whole story. But speaking strictly of sonics, I probably would be happy with either one. But the extra $$ the d70s cost over the su9 is worth it to me. And most importantly, it just plain works, while there has been a few issues reported with the similar measuring su9.

 

[Lupin]

When I purchase a new HiFi equipment (or build one) that contains elec. caps in its PS, I usually leave it running 24/7 for up to 200 hours with occasional critical listening to get a feel on the changes in sound quality. Really simple and 200+/- hours should be adequate to reform the cap in my opinion. You know it when the sound reaches its optimal state without further improvement. YMMV.

Humans have a reliable audio memory of a couple seconds at best.. so how are you or anyone else able to say anything meaningful about the sound quality now and after 200 hours..

Only thing that happend is that your brain got accustomed to the sound after 200 hours which means you can tolerate it more/easier and so perceive it as more enjoyable/better.

 

[Skinner001]

Well this supposed thread about the D70s has devolved to things like burn-in and cables.

The more you listen to new gear the better it sounds - you accommodate to any quirks, you build up subjective arguments for spending the money, and you usually become more satisfied. If it makes you happy, great, though any perceived differences are just that, perceived. The opposite can also happen, you spend a lot of cash and expect to be lifted to another plane of existence compared to your old gear, but it doesn't happen and now it becomes worse than your old stuff, dull, flat, unenjoyable, flawed. All of that without sound quality even figuring in there.

And if you haven't been listening, just having it run for 200 hours then coming back to it, or looking in on it occasionally - then it's entirely about belief, if you believe burn-in is a thing then it will be, because you sure as shit don't remember enough to clearly notice any very subtle differences. If the differences aren't subtle, and the sound changes completely, time to take advantage of your guarantee and return the thing.

I guess it's to be expected, delusional thinking is pretty accepted in society with a large proportion still believing in one god or another. But hasn't this gone quite a bit away from the product in question...

 

[BDWoody]

But hasn't this gone quite a bit away from the product in question...

Indeed. A new thread would be more appropriate, rather than further derail this thread.

Or, just pick one of the many 'burn-in' threads and revive it. Many to choose from.

 

[Raindog123]

we’re discussing the impact on SQ and not functionality of the equipment.

SQ _is_ the functionality of a DAC.