Latest US beta version was released almost 2 weeks before on Aug 10th... Normally this is the case where we receive the latest FW first then other countries receive it later on.
Sounds about right. The Tidal thingy seems to be the main thing.
Down here Tidal Premium will be AUD $11.88/month and Tidal Hi-Fi AUD $23.99 the question is what you get for the premium? Evidently not lossless, so the name Premium sounds like a misnomer.
You do make full disclosure of what you do so any ambitious DIY'er could do it themselves, I might be bothered by a lack of due diligence in rationalizing technically what is going on but that is a different issue.
You do see how this leads to a kind of relativism? The random plug it in and see what happens folks are on equal ground with those that have dedicated a portion of their careers/lives to the art. The great equalizer is the true unbiased blind test of the results, resisted with good reason by one side, hence the eternal impasse.
It has been my experience that the OPPO 105 is not a perfect performer as delivered, even though it is one heck of a bargain for the amount of engineering put into it. At a recent hi fi show, I met someone with a MODIFIED 105, and it did sound better: Tubes were added! We both confirmed that it is in the ANALOG portion that there seems to be the biggest problem. I met a senior engineer of the 105 project at the hi fi show, and I was reminded of his resistance to my recommendations. Oh well!
PS Double blind tests do not work well (if at all) at this level.
PS Double blind tests do not work well (if at all) at this level.
Swap out the LM4562s for LM6172. Delete the 100pF feedback capacitors. Bias the opamp output stage into classA with a CCS (try 5mA) to the -ve rail. Then sit back and enjoy....
Of course you don't. It doesn't always give you your desired outcome. Experiments are like that sometimes. 😀
Go ahead and peek. That's the standard MO for the huckster side of audio.
Go ahead and peek. That's the standard MO for the huckster side of audio.
Thanks Abraxalito, you have given me some real input. WHY the 4562 has to be replaced is a still a mystery, but class A biasing is obvious. I would really like for this 105 to work well enough to 'enjoy' on a consistent basis. I am not the only one, certainly.
Its not very much more than conjecture based on plenty of anecdotes but opamps with bipolar LTPs don't seem to fare very well in high RF environments. A DAC I/V converter is about as high a level of RF its possible to find in an audio circuit.
The LM6172 is internally a CFB design but they've included an input diamond buffer to make it externally just like a VFB amp. It still has the high slew rate and wide bandwidth of a CFB amp though.
The LM6172 is internally a CFB design but they've included an input diamond buffer to make it externally just like a VFB amp. It still has the high slew rate and wide bandwidth of a CFB amp though.
AND THAT IS EXACTLY WHAT WE ARE ABOUT TO DO !!!
That was always the intention - but the noise always drowned that out - something is happening behind the scenes and Scott, you will get everything you want and more on the front, so please (yes please) be a bit more patient. About a week.
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The LM6172 being a CFA design looks to be better than the LM4562, because it has a better slew rate AND a higher open loop bandwidth (typical of CFA IC's, compared to VFA IC's like the LM4562).
Hear, hear !!!
Dan Wright?
There I differ.
I would love to get my hands on his (ModWright I assume) 105 and be itching to do something very basic and very audible as an example. What it is, will actually be part of a new thread that the Moderators have decided they will allow, but will be very strictly moderated because of past experience.
Scott Wurcer has demanded (and I think rightly so) to "make full disclosure of what you do so any ambitious DIY'er could do it themselves" and that was always my intention. So that is what he will get and avoid the noise, confusion and misunderstandings and errors of the past.
Interesting as this was the thread, this Oppo 105 thread, where it originally broke and then all hell let lose. Now I suppose I have made an announcement of sort - next week or so, but this time it will be DIY that can be tested - and it will be limited to that and possible explanations.
May the peace break out.
For a start, they are completely impractical for the average DIYer.
I am reminded going back to the 70's and 80's where Martin Colloms (and Atkinson too if my memory serves me right) were into controlled listening tests. They are wonderful to study for those who have that kind of heady bent, you can certainly spend a lot of time and effort to set them up and I can sorta see the fascination with them. But alas, ask Colloms about them now and he will tell you his position and thoughts have changed a lot. It comes down, in my mind, that the subject (not the equipment) is still the weakness in the chain - and judgement is impaired under stress. Just ask a question, whether on paper or vocally, same thing.
When I play something to somebody walking in, a demonstration, I never ask "what do you think" - in fact (many who have been here will testify this is true), I start talking to them about the music we are playing, the history of the piece, what instrument is that, various versions or covers, what should we play next... and so on. Set them at ease without even knowing and eventually they will come around and state their unpressed opinion. The other method I like is as old as it gets, the old placebo effect. Do something to their player, but tell them it will be done at a toss of a coin. Get them to report back. No blind tests can have 100% results but my feedback has been 100%. It's actually not that hard, tell them to take it home and make their own judgement in a non-threatening way. No better place than doing it at home.
Cheers, Joe
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If I may, I might have a paper that more fully describes the difference between the LM4562 and the LM6172, or VFA vs CFA. It is entitled: Current-Feedback Amplifiers Versus Voltage Operational Amplifiers, by G. Palumbo and S. Pennisi, from IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS, No.5 May 2001 pp. 617-623. Give it a look!
Here is an interesting thought:
"Psychological research found that we all suffer from what is known as the “bias blind spot”. This is the illusion that we all tend to be confident that our own decisions are made objectively and rationally, but happily infer that others suffer from bias when making their decisions."
"None of this is an intentional mis-assessment of bias. But it may go some way to demonstrating the shortcomings of adhering to the view that tests can be applied with absolute objectivity."
Source: "The Conversation, Academic Rigour, Journalistic Flair" - August 21st 2015
Objectivity? Yes. Absolute objectivity? Doubtful.
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"Psychological research found that we all suffer from what is known as the “bias blind spot”. This is the illusion that we all tend to be confident that our own decisions are made objectively and rationally, but happily infer that others suffer from bias when making their decisions."
"None of this is an intentional mis-assessment of bias. But it may go some way to demonstrating the shortcomings of adhering to the view that tests can be applied with absolute objectivity."
Source: "The Conversation, Academic Rigour, Journalistic Flair" - August 21st 2015
Objectivity? Yes. Absolute objectivity? Doubtful.
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I did this indeed, changing the original opamps for quite long time ago. Also the 100p feedback caps there was not a very fortunate choice, but they use it to filter out enough high HF noise... These caps it affect quite much the resulting sound quality.
Finally I decided to implement the fully and straight differential OP1632 for both I/V and as final buffer. Your suggestion for a class A buffer is of course a very good solution too.
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Nonsense. It's especially nonsense if you're selling something, where it might be expected that you'll go to the trouble of providing proof that what you're selling does what it claims. That strikes me as the first obligation of a merchant, to verify that what he's selling does what he claims.
“It is difficult to get a man to understand something, when his salary depends upon his not understanding it!” Colloms is selling his exquisite perceptions via his magazines.
Your Clever Hans coaching anecdote is too typical of "high end" audio. Throwing in your lot with hucksters does not become you. If you can't hear the difference between X and Y without peeking, you can't hear the difference. It's really that simple.
I've spent some enjoyable time with you and my impressions were that you were a good guy; why not take the opportunity to separate yourself from the con-artists that have so badly polluted audio? Looking forward to seeing some measurements that support (or refute) your hypothesis. I can only hope that you'll reconsider and do some valid listening tests toward the same end.