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Investigation Into Effects Of PC load On DAC Analogue Output


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Have you tried it with a regular PSU PC? I am just curious is all.

 

I am wondering if the DAC design could be down to USB chip used? Many of the SMAL and Toppings use the same USB chip set. I also wonder about some older DAC designs (I have one) like a TEAC UD-501.

 

Thank you for your measurements!

 

Just another Fun-Gi among us (I had to counter Savant 🤣 )

Current:  Daphile on an AMD A10-9500 with 16 GB RAM

DAC - TEAC UD-501 DAC 

Pre-amp - Rotel RC-1590

Amplification - Benchmark AHB2 amplifier

Speakers - Revel M126Be with 2 REL 7/ti subwoofers

Cables - Tara Labs RSC Reference and Blue Jean Cable Balanced Interconnects

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2 hours ago, firedog said:

Maybe you didn't read the whole thing at ASR or the other threads on the topic. The point was the ISO Regen lessened the noise, but only with a DAC that is essentially "broken" b/c of improper design. With other DACs it made no difference. 

Same for other DACs - except for a small minority that are improperly designed, March Audio's results hold. Conclusion: the PC doesn't matter for these measurements, unless you have a DAC that is inherently defective. 

Archimago did similar testing at his site a while back and got the same results. 

The whole thing? If you mean the whole 2 page thread, I did. And other DAC threads too. Did you? Amir made assumptions: he didn't locate the noise source; he read the brochure which said "isolated", but not "galvanically isolated", so he assumed it was defective. It may be, but I don't accept that type of assumption without evidence.

 

There is a common technique of stating that all "competent" or "properly-designed" DACs behave [the way you say - whatever you want], with the convenient response to any counterexample as being "broken" or "defective". You're guaranteed to always be right, since you made the definitions.
There was a $1000 bet on another site (not the recent one on ASR), where the person proposing the bet would allow the I-can-hear-a-difference claimant to pick any 2 "competent" DACs. He warned of DACs that were deliberately or unintentionally "defective". He said pick any 2 that had been tested with SINADs over "say... 100dB". I noticed that of the many DACs that Amir had tested, the median was about 100. So by the challenger's admittedly random cutoff, nearly half the DACs tested were defective. You didn't make that bet, but I wonder how useful a term like "defective" is if it applies to too many examples. The rule-of-thumb that's intended to use it may be weak, maybe a rule-of-pinkie.

 

The fact is that a "defective" DAC may function well with a low-noise PC, as will a "competent" DAC with a noisy, but within spec, PC. What about PCs that are nearly in spec, but not quite (noise on USB lines slightly too high)?

 

@March Audio has shown that his PC with (now 2) DACs performs certain tests well. Great, and I appreciate his effort. My concern is that if the goal is to convince members who "hear a difference" in whatever (don't think the motivating threads were simply about DACs), or to convince them they have defective hardware, this method may not work. And there are better, more efficient, methods. @firedog do you think this can convince the target group? I don't think convincing people who are already convinced was the goal. I do not wish to dissuade @March Audio from continuing... so I'll probably continue with the issue of convincing skeptical people in another thread.

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8 minutes ago, SoundAndMotion said:

There is a common technique of stating that all "competent" or "properly-designed" DACs behave [the way you say - whatever you want], with the convenient response to any counterexample as being "broken" or "defective". You're guaranteed to always be right, since you made the definitions.

 

Since I can't measure myself the differences which can easily be heard by all those who are open to it, including myself, I don't care much.

All those who are not open to this and (think they can) measure, obviously won't see any "significant" difference.

And the definition of "significant' is indeed ...

Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

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10.1177_2041669515607153.pdf

59 minutes ago, PeterSt said:

 

Since I can't measure myself the differences which can easily be heard by all those who are open to it, including myself, I don't care much.

All those who are not open to this and (think they can) measure, obviously won't see any "significant" difference.

And the definition of "significant' is indeed ...

 

 

That is not the point - @idiot_savantsaid it best. I think there are people that go overboard on both sides of the discussion. 

I think, in play, with this argument is called expectation bias. If you think you will hear something different, you will. Your brain is amazing for filling in all that. Hence, why the only way to truly determine if there really is noise or not is by DBT. But, that is for another discussion/thread.

 

We are here to talk about the current topic.

Current:  Daphile on an AMD A10-9500 with 16 GB RAM

DAC - TEAC UD-501 DAC 

Pre-amp - Rotel RC-1590

Amplification - Benchmark AHB2 amplifier

Speakers - Revel M126Be with 2 REL 7/ti subwoofers

Cables - Tara Labs RSC Reference and Blue Jean Cable Balanced Interconnects

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18 minutes ago, botrytis said:

I think there are people that go overboard on both sides of the discussion. 

I think, in play, with this argument is called expectation bias.

 

Both true.

What is the most important - my personal view - is that we are all having a great hobby, but those who are telling me and others that I better quit this hobby because all sounds the same anyway, are making me object against that. Mind you, I contribute to this hobby largely for many, say starting with myself. That I contribute in an area which is hard to understand ... so be it ?

It is still so that I am the only one who could clearly show the differences between players in a most discrete manner. This remains useless as long as people keep on saying that "this will be beyond audible levels". And as long as this remains to be so, I am just showing the differences and know that it is that what I am listening to for (hey, huge) differences.

Mind you please, what AmirM does with his under 120dB whatever is inaudible is more extreme, but still very much the same as "there is no significant difference". It is thus all about that. Who is going to finally tell what is significant.

 

The differences I am talking about are fully controllable and repeatable. BUT they are measuring-wise over 90dB down.

 

PS: May it help someone, ... a single test signal is quite useless. A 100 fold IMD could show more.

PPS: My earlier remark about "as long as I myself can't measure it" is about the regular means by Audio Analyzer and such. No-single-way.

Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

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2 hours ago, SoundAndMotion said:

He warned of DACs that were deliberately or unintentionally "defective". He said pick any 2 that had been tested with SINADs over "say... 100dB". I noticed that of the many DACs that Amir had tested, the median was about 100. So by the challenger's admittedly random cutoff, nearly half the DACs tested were defective.

That's interesting interpretation. Mine is, that by setting such cutoff he just wanted to filter out those that might be 'deliberately or unintentinally "defective"', not that he considered all of them to be defective.

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Now, strictly speaking, the complaints about PC activity have always been about “noise”, which IMD is clearly not ( clues in the name ). However, in a spirit of open-mindedness, I certainly wouldn’t object to such a test - maybe we should get the precise IMD setup required?

 

I can understand why @March Audio wouldn’t have done this - he’s been concentrating on noise, as this has been mooted as the problem. 
 

your friendly neighbourhood idiot 
 

 

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2 hours ago, idiot_savant said:

but I thought you were a manufacturer? Isn’t that different from being a hobbyist?

 

It is. But it is not really if the hobby is your drive and motivation for sharing. The derived commercial business should only not "cost" as such (but could bring money because of doing well).

This makes the hobby as decent as imaginable (the resulting product is to recur xxx(s) times) and does not allow for false allegations (to self) and allows for explicit confirmation (by customers). The explicit method incurs for improvement (nothing goes out if I myself don't approve it - nothing at stake but honors).

 

Please don't underestimate the investments. This is nothing hobby-like. It is 10K number of chips here and 10 miles of cable there. What might lack is the 300K of analyser. But hey ...

 

I hope this comes across as intended. For Alan just the same, who spends a tremendous time on his honors just the same. Appreciated !

We all try our very best.

Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

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Turns out that it's quite easy to see differences in the waveform, where it counts, which is the sound waves in the room -  @manisandher recorded what was happening when he altered settings of Peter's player; which had clearly audible variation, and this was quite distinct in the recordings when examined with DeltaWave. We were promised a more thorough version of this exercise, to overcome those who went into a mad thrash about microphone technique and everything else they could think of - but this has not eventuated.

 

Interesting how all investigations into things like this either bog down, or die a slow death - an instinctive reluctance not to rock the boat too much, perhaps ... ?

Frank

 

http://artofaudioconjuring.blogspot.com/

 

 

Over and out.

.

 

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1 minute ago, fas42 said:

Turns out that it's quite easy to see differences in the waveform, where it counts, which is the sound waves in the room -  @manisandher recorded what was happening when he altered settings of Peter's player; which had clearly audible variation, and this was quite distinct in the recordings when examined with DeltaWave. We were promised a more thorough version of this exercise, to overcome those who went into a mad thrash about microphone technique and everything else they could think of - but this has not eventuated.

 

Interesting how all investigations into things like this either bog down, or die a slow death - an instinctive reluctance not to rock the boat too much, perhaps ... ?

 

Any clues as to how any of this is related to this paper or the experiment? Was Mani or DeltaWave or Peter involved in the process somehow? Didn't see them mentioned, I'm afraid.

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6 hours ago, SoundAndMotion said:

The whole thing? If you mean the whole 2 page thread, I did. And other DAC threads too. Did you? Amir made assumptions: he didn't locate the noise source; he read the brochure which said "isolated", but not "galvanically isolated", so he assumed it was defective. It may be, but I don't accept that type of assumption without evidence.

 

There is a common technique of stating that all "competent" or "properly-designed" DACs behave [the way you say - whatever you want], with the convenient response to any counterexample as being "broken" or "defective". You're guaranteed to always be right, since you made the definitions.
There was a $1000 bet on another site (not the recent one on ASR), where the person proposing the bet would allow the I-can-hear-a-difference claimant to pick any 2 "competent" DACs. He warned of DACs that were deliberately or unintentionally "defective". He said pick any 2 that had been tested with SINADs over "say... 100dB". I noticed that of the many DACs that Amir had tested, the median was about 100. So by the challenger's admittedly random cutoff, nearly half the DACs tested were defective. You didn't make that bet, but I wonder how useful a term like "defective" is if it applies to too many examples. The rule-of-thumb that's intended to use it may be weak, maybe a rule-of-pinkie.

 

The fact is that a "defective" DAC may function well with a low-noise PC, as will a "competent" DAC with a noisy, but within spec, PC. What about PCs that are nearly in spec, but not quite (noise on USB lines slightly too high)?

 

@March Audio has shown that his PC with (now 2) DACs performs certain tests well. Great, and I appreciate his effort. My concern is that if the goal is to convince members who "hear a difference" in whatever (don't think the motivating threads were simply about DACs), or to convince them they have defective hardware, this method may not work. And there are better, more efficient, methods. @firedog do you think this can convince the target group? I don't think convincing people who are already convinced was the goal. I do not wish to dissuade @March Audio from continuing... so I'll probably continue with the issue of convincing skeptical people in another thread.

The goal is to objectively investigate and show what's actually going on as opposed to just guessing.  You wont convince believers with entrenched views of anything, I have no illusions about that.  However there are still plenty of people our there who will be interested in the investigation.

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Quote

Any clues as to how any of this is related to this paper or the experiment? Was Mani or DeltaWave or Peter involved in the process somehow? Didn't see them mentioned, I'm afraid.

 

Ahem. Alan uses one setup and measures nothing changing; Mani uses another setup, and a different technique for exercising the PC, and measuring - and records a significant difference ... who is correct?

Frank

 

http://artofaudioconjuring.blogspot.com/

 

 

Over and out.

.

 

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6 hours ago, PeterSt said:

 

Since I can't measure myself the differences which can easily be heard by all those who are open to it, including myself, I don't care much.

All those who are not open to this and (think they can) measure, obviously won't see any "significant" difference.

And the definition of "significant' is indeed ...

You haven't actually demonstrated using controlled techniques that people can hear a difference.

 

Later I intend to perform controlled listening tests.

 

 

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Just now, pkane2001 said:

 

What does this have to do with the experiment at hand? Mani's test was nothing like the test Alan performed.

 

I do appreciate that Alan's test has almost nothing to do with how people actually use their audio setups; and that Mani's is about a real life situation of listening to an actual recording ... yes.

Frank

 

http://artofaudioconjuring.blogspot.com/

 

 

Over and out.

.

 

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3 hours ago, semente said:

Since these measurements don’t show the effects of “PC load”, which other measurements could be performed?

Peter has already suggested multi-tone IMD. Anything else?

Multitone is no problem to try.  Will do later.  However I can tell you now that it won't make any difference.  IMD is directly related to THD.  If the PC load is having no effect on thd (as already seen), it won't effect IMD.

 

I'm happy to field other suggestions for tests.

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40 minutes ago, fas42 said:

Turns out that it's quite easy to see differences in the waveform, where it counts, which is the sound waves in the room -  @manisandher recorded what was happening when he altered settings of Peter's player; which had clearly audible variation, and this was quite distinct in the recordings when examined with DeltaWave. We were promised a more thorough version of this exercise, to overcome those who went into a mad thrash about microphone technique and everything else they could think of - but this has not eventuated.

 

Interesting how all investigations into things like this either bog down, or die a slow death - an instinctive reluctance not to rock the boat too much, perhaps ... ?

As discussed elsewhere recording with a microphone in a room is hopelessly insensitive and will pick up all sorts of irrelevant random background noise.

 

With all respect to Mani, unfortuntely Its a hopelessly flawed method.  Of course you will see differences in the waveform.  However these differences will have nothing to do with the PC or audio system.

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6 hours ago, PeterSt said:

 

Since I can't measure myself the differences which can easily be heard by all those who are open to it, including myself, I don't care much.

All those who are not open to this and (think they can) measure, obviously won't see any "significant" difference.

And the definition of "significant' is indeed ...

I'm open, however I am looking for evidence. Otherwise it is just faith.

 

Significant?  Well my definition of insignificant is when you can't see any changes at -180dBFS.

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8 minutes ago, March Audio said:

As discussed elsewhere recording with a microphone in a room is hopelessly insensitive and will pick up all sorts of irrelevant background noise.

 

With all respect to Mani, unfortuntely Its a hopelessly flawed method.  Of course you will see differences in the waveform.  However these differences will have nothing to do with the PC or audio system.

 

First of all, the background noise can be made to be relatively consistent - to test this, merely record the same playback, with no changes, several times to establish the consistency of the recording space.

 

Secondly, what you are looking for are patterns in the waveform which consistently register as being different at certain points in the music - say, a treble crescendo, or transient. These are the "tells" that one's ears are sensitive to, and which are meaningful.

Frank

 

http://artofaudioconjuring.blogspot.com/

 

 

Over and out.

.

 

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6 hours ago, idiot_savant said:

@SoundAndMotion there seems to be a bit of crossed purposes here. I myself have said on a forum, you’re unlikely to “convert” people who are entrenched, but if you let some of the more outrageous claims go unchallenged, people who are maybe unconvinced need a bit of a sensible voice to help a bit of balance?

I think the point @March Audio is trying to make *isn’t* that all PC’s with all DACs are perfect, but that with a bit of care, you don’t need a PC encased in unobtanium to get really good performance. 
 

As for specs, most well-engineered stuff tends to have a margin of error built in, and good engineering in one place *can* indicate overall good engineering, whereas bad engineering in one area tends to indicate a trend

 

your friendly neighbourhood idiot 

This is the point.

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