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Hardware Mods - the ugly story

Palladium

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Yes, if you make claims, you must supply evidence.
If you can't or won't your most likely FOS

I'm suuuuuure this is not going to boil down to the same old tactic of unfalsifiable claims ever. *snicker*
 

rebbiputzmaker

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So you weren't interested in using the results of blind testing to make purchasing decisions?
Never went that deep where I felt it mattered when buying something. Never got that OCD, plus I always built/ designed or purchased things used. Never went audiophile nuts and spent crazy money. Always happy with my sound which was my first consideration. When I had large systems, they were horns designs mostly Altec or JBLs stuff with different reflex bass iterations, i.e. VOT or Onken type cabs. Never had room or really wanted full bass horns. Preferred triode over pentode designs, and never needed big power.
 

restorer-john

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I am confident in controlled testing, those 1980s CD players would not be distinguishable by vast majority if not all the audiophiles from the best of the best high-end players today.

I have plenty of early 1st/2nd gen machines and could quite easily make some level matched (in the analog domain) recordings into say an M-Audio 24/96, DAT front end or equivalent/greater for comparison purposes.

Trouble is, it is trivial now to analyze the recorded waveforms to look for telltale 'differences' prior to listening and proclaim 'night and day' differences replete with expectation bias.

I agree wholeheartedly that the majority of Audiophiles could not distinguish many if not most CD players from one another. I think it would be a very easy bet to win.
 

restorer-john

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Unfortunately it is a given that audible differences existed in players then.

It is not a 'given', never was.

What 100% functional 1st gen machines do you have, that can demonstrate those 'audible differences'?

Hint: I can put my hands on 5 or 6, 1st gen Sony CDP-101s, one is sitting on my floor right now. I've got some 1989/90 TOTL Sony CDP-X7esds sitting here (3) a few Sony CDP-338esds, several 1990 Onkyo DX-6/708 Integra players, A Marantz Pro PMD325 and the piece-DE-resistance, a Marantz CD12/DA12LE sitting all within view of my test bench as I type. All of those are pre 1991. (except the PMD-325)

I can easily grab some early Philips from the storeroom and there's a bunch of 1984/5/6 machines I've given to my Dad to play with which I could get too. (He's a super HiFi buff too), including some vertical Kyocera units (Akai CD-D1), a 1st gen Pioneer and even a Philips CD-104 someplace.
 
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March Audio

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Wow Fitz, you sure like to make up stuff to suit your agenda to defame. Seems to be a regular pattern of yours towards John and I (I could go back into the archives and quote a half-dozen examples but I have better things to do with my time).
Just to be clear for you an others regarding your latest falsehood:

a) John does not and has never offered any "modding" services to anyone.

b) He has designed and built from scratch a dozen+ analog and digital components over the years (aside from also engineering the bowls of some of the worlds most sophisticate ASICs--the sort in enterprise network gear).

c) The completely unique commercial designs he has done in recent years (for Sonore: the Rendu series, and UpTone: the REGENs, and the UltraCap power supplies) have not only combined sold millions of dollars worth, but have spawned a market of similar copycats and inspired numerous other firms to reconsider and explore several taken-for-granted aspects of computer audio.

d) His engineering lab (custom built with quartz countertops, isolated power systems, and ultra-low-emmisons lighting) is outfitted with over $65K worth of test gear, including a $27K 4GHz scope, a spectrum analyzer with both real-time and FFT storage capabilities, and an in-progress 32-bit high-speed A-D rig that may eventual surpass some specific Audio Precision capabilities for the particular work he is doing (Wavelet analysis to prove the impact of upstream clocking variations on the analog output of the DAC). In addition, his set up includes for prototyping a vapor-phase reflow oven (capable of mounting BGA and all other hidden-pad SMDs) and a pick-and-place machine (hand placing hundreds of tiny parts gets old!).

e) Plenty of measurements are made on every product we work on. That is how design is done! Some of those measurements we elect to publish, but, like most every other audio firm out there, we don't publish reams of basic measures since only a few are going to correlate to sonic end result. If/when John makes the breakthroughs he is looking for with regards to demonstrating how digital isolation and reclocking upstream affects analog output (first by showing a defined, artificial jitter marker getting through), then we will offer up plenty--and may again bust past a bunch of preconceived notions about things that matter in digital audio reproduction.
[Some of this last paragraph is in reaction to another post you just made--in the ISO REGEN thread--where you ridicule someone for purchasing our competitor's 3x the price product and call this whole segment of the market nonsense. How much research and engineering have you done Fritz? Does none now qualify you?

-Alex C.

Yes Alex thank you. You have just confirmed the point that was made that he still does not have appropriate test equipment for audio design and that he still has no measured evidence that the products like regen and PSU do anything beneficial .

Sales are irrelevant. Audiophiles imagine all sorts of erroneous things and draw false conclusions due to the uncontrolled nature of their comparisons. Yes many hifi companies take advantage of this and the general state of technical ignorance to market these non useful devices.
 
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Frank Dernie

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I now realise having somebody on the ignore list can sometimes make a thread difficult to follow :)
 

Jakob1863

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I'm not making any claims about 'everyone's listening abilities, but the measurements made at the time indicated that those shared DACs players were no worse than separate DAC players, except for the tiny interchannel time difference, which, as I said above, was comparable with moving one's head a few millimeters. Frequency response, noise and distortion were quite satisfactory, so no reason there for any sonic difference.

S
Ah, sorry i did read your statement as related to the general population while you meant it in the same context as before, means related to your experience and that of your staff.
Please accept my apologies for the misinterpretation.

This tiny interchannel time difference might be considered as irrelevant but it was found in the 1960s that humans can detect ITDs down to 10 µs, which means for statistical reasons that most likely some listeners will be able to detect ITDs even lower, and these findings were corroborated in a lot of follow up experiments over the decades.

Low level linearity of DACs was of course already an issue in the first CD players but afair neither was routinely measured in reviews nor specified by player manufacturers, so was indeed an additional reason for sonic differences.
 
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Jakob1863

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No we don't agree. You can't say multiple times there were audible differences and then finish by saying you will provide evidence when you are good and ready. We don't waste forum member's time here with empty debates. Where is the data?
As said before, i´ll always provide evidence and if i later detect to have erred i post that too, something that i consider as crucial for any sound discussion. So i encourage you strongly to do the same and to restrain from using eristics.

Further, sorry but you should know it already. We all do sometimes forget things or misinterpret something (as i unfortunately did above in the discussion with sergeauckland) but by now you should have remembered that the result of using a single DAC chip for both channels is/was a constant interchannel (or interaural) time difference (hence the acronym ITD) of 11.3 µs .

And of course i´ll cite a bunch of publications with evidence for the audibility of such an ITD, but still, it is in my discretion when.
 
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amirm

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Further, sorry but you should know it already. We all do sometimes forget things or misinterpret something (as i unfortunately did above in the discussion with sergeauckland) but by now you should have remembered that the result of using a single DAC chip for both channels is/was a constant interchannel (or interaural) time difference (hence the acronym ITD) of 11.3 µs .
So you are now modifying your statement that it was only in the context of the ones (Technics) that used a single DAC that was multiplexed between channels than all CD players of that era?

And of course i´ll cite a bunch of publications with evidence for the audibility of such an ITD, but still, it is in my discretion when.
Instead of citing evidence of clear audibility between CD players you said was the case?
 

Thomas savage

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As said before, i´ll always provide evidence and if i´m later detect to have erred i post that too, something that i consider as crucial for any sound discussion. So i encourage you strongly to do the same and to restrain from using eristics.

Further, sorry but you should know it already. We all do sometimes forget things or misinterpret something (as i unfortunately did above in the discussion with sergeauckland) but by now you should have remembered that the result of using a single DAC chip for both channels is/was a constant interchannel (or interaural) time difference (hence the acronym ITD) of 11.3 µs .

And of course i´ll cite a bunch of publications with evidence for the audibility of such an ITD, but still, it is in my discretion when.
Do you have anything other than doubt to inject? That’s all I see from you, you bring doubt .. for doubt sake it seems to me.

No objective, I don’t really understand what it is you stand for despite the pages apon pages you post.. possibly my false , I am after all a humble work horse.
 

Jakob1863

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So you are now modifying your statement .......

No, i don´t modify my statement, because my statement was:
<snip>

I hope we can agree that "distinguishable by vast majority" is a (totally) different topic?!


Unfortunately it is a given that audible differences existed in players then.
(bold feature activated now by me)

1.) you forgot to answer, if we agree that "distinguishable by vast majority" is a (totally) different topic
2.) if you read the bold line as "difference in all and every player" then you misinterpreted it

But with what do you disagree?
At least it is known that CD players using only one DAC ic intermittently for both channels were audible different.
An no,that does not mean that _everyone_ could reach a positive "blind" controlled listening test result under all conditions.

<snip>
(bold feature now activated by me)

...that it was only in the context of the ones (Technics) that used a single DAC that was multiplexed between channels than all CD players of that era?


Instead of citing evidence of clear audibility between CD players you said was the case?

See above, i was already then stating that at least it was a given for CD players using only one DAC ic ......

Hint 1, if you would just cite my assertions, instead of straining your imagination, that you want to address, you would be simply more often correct. ;)

Hint 2, i explicitely referred to the argumentation that was used in the past to back the assertion of "impossible audible differences" .......
 

andreasmaaan

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As said before, i´ll always provide evidence and if i later detect to have erred i post that too, something that i consider as crucial for any sound discussion. So i encourage you strongly to do the same and to restrain from using eristics.

Further, sorry but you should know it already. We all do sometimes forget things or misinterpret something (as i unfortunately did above in the discussion with sergeauckland) but by now you should have remembered that the result of using a single DAC chip for both channels is/was a constant interchannel (or interaural) time difference (hence the acronym ITD) of 11.3 µs .

And of course i´ll cite a bunch of publications with evidence for the audibility of such an ITD, but still, it is in my discretion when.

I was well aware of the research showing audibility of very small ITDs, but in fact it is news to me that any stereo DAC that uses a single DAC IC for both channels has an inherent ITD of 11.3µs.

This is probably not the thread to delve into this directly, but if you would be able to quickly link some further info for me to do my own reading, I'd much appreciate it.

Andreas
 
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Fitzcaraldo215

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No, i don´t modify my statement, because my statement was:

(bold feature activated now by me)

1.) you forgot to answer, if we agree that "distinguishable by vast majority" is a (totally) different topic
2.) if you read the bold line as "difference in all and every player" then you misinterpreted it


(bold feature now activated by me)



See above, i was already then stating that at least it was a given for CD players using only one DAC ic ......

Hint 1, if you would just cite my assertions, instead of straining your imagination, that you want to address, you would be simply more often correct. ;)

Hint 2, i explicitely referred to the argumentation that was used in the past to back the assertion of "impossible audible differences" .......
Weaving and bobbing, sentence parsing as usual. I am afraid I have to give it Thomas Savage and Amir. Have you actually got anything of any relevance? No, as we know full well. So, I am quite sure you are just doing this vacuous nonsense to get attention. Meanwhile, you have added essentially nothing except quarrelsomeness. Alas and alack, you deserve the immortal Ignore button. Bye!
 

restorer-john

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I was well aware of the research showing audibility of very small ITDs, but in fact it is news to me that any stereo DAC that uses a single DAC IC for both channels has an inherent ITD of 11.3µs.

A single D/A converter does not and did not mean a constant 11.3uS interchannel time delay.

Some machines, including the CDP-101 attempted to adjust time constants in S/H to minimise that time delay, and consequently, back in the day, interchannel phase differences were typically tested and displayed in decent reviews at various spot frequencies up to 20KHz as a Lissajous CRO image.

Single D/A machines were not all the same in that regard.
 

Palladium

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Weaving and bobbing, sentence parsing as usual. I am afraid I have to give it Thomas Savage and Amir. Have you actually got anything of any relevance? No, as we know full well. So, I am quite sure you are just doing this vacuous nonsense to get attention. Meanwhile, you have added essentially nothing except quarrelsomeness. Alas and alack, you deserve the immortal Ignore button. Bye!

He's just a concern troll by the textbook.

Call me cynical, but it's easy to see why they are doing so on this forum, when this forum threatens the very existence of an entire snake oil industry and the sensibilities of their customers.
 

amirm

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No, i don´t modify my statement, because my statement was:
Looks like you have forgotten your own story. Let me remind you properly:

Actually the discussion and arguments remained the same for the last 40 years but the topics do change. I remember the first CD player tests describing sonical differences despite quite similar measurements and the angry reactions by EEs who pointed out that it wasn´t possible that any audible difference exists.

There is no talk of multiplexed DACs. A blanked ridicule of engineers was made about CD having audible differences but two pages later, you are trying to get yourself out of that pickle by changing the story to single DAC CD players. And even there, nothing has been shown whatsoever to indicate audible problems let alone to the extent to back the original story.

Hint 1, if you would just cite my assertions, instead of straining your imagination, that you want to address, you would be simply more often correct. ;)
Hint back to you: the fastest way you can get yourself booted out of this forum is by being obnoxious. I don't care if you are objectivist, or subjectivist. I don't care if you back what I say or the opposite. Forget our mission statement which says we are here to have fun and your participation in this forum will end. None of us want to come here and get aggravated, much less by someone who is trying to play cat and mouse with us with data.

Your next post needs to be constructive, have data in it to discuss, and friendly in nature. If it is not, it will be your last post and it will be because of you, not us.
 

andreasmaaan

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A single D/A converter does not and did not mean a constant 11.3uS interchannel time delay.

Some machines, including the CDP-101 attempted to adjust time constants in S/H to minimise that time delay, and consequently, back in the day, interchannel phase differences were typically tested and displayed in decent reviews at various spot frequencies up to 20KHz as a Lissajous CRO image.

Single D/A machines were not all the same in that regard.

Thanks John :)

Just to clarify: you're saying this is an inherent problem in all DACs, but that in some DACs it is compensated for in S/H. Is that correct?

And is there any reason that these tests are not performed these days? Is the problem long solved?
 

restorer-john

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And is there any reason that these tests are not performed these days? Is the problem long solved?

Yes, long solved with the implementation of twin L/R D/A converters and timing corrections in the O/S digital filters.

That said, there are still some very minor phase differences observed on players that shouldn't exhibit differences.

I'll take a few XY scope shots on the weekend and post them into this thread for fun.
 

andreasmaaan

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Yes, long solved with the implementation of twin L/R D/A converters and timing corrections in the O/S digital filters.

That said, there are still some very minor phase differences observed on players that shouldn't exhibit differences.

I'll take a few XY scope shots on the weekend and post them into this thread for fun.

Ah yes, sorry I should have stated the question more clearly: is the problem now solved in respect of single D/A chip DACs?

EDIT: and if the problem is not solved completely, would @amirm considering measuring for inter-channel phase differences when he reviews each unit?
 

SIY

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Ah yes, sorry I should have stated the question more clearly: is the problem now solved in respect of single D/A chip DACs?

Yes, as of about 1985 or so. Single chips from the last 30-35 years have two separate D/A converters.

Generally, the "problem" was just a constant time delay in one channel, which wasn't really a problem, since it could literally be fixed by shifting one speaker a couple of millimeters. The first CD players also only had 14 bit converters, but again, that "problem" was solved within a year or two as new chips became available. That could be audible as a slightly increased noise floor if you boost the volume during extremely quiet passages.
 
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