Stuart, please, just give it a chance, that's all we are asking for. Scott has asked for "full disclosure" and that is what is coming. Everything will be testable. We need to cool it, it's about a subject that has been so disfigured and caricatured that it has no resemblance to what it actually is.
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Joe, remember that I said, "Looking forward to seeing some measurements that support (or refute) your hypothesis." So, we're in violent agreement. 😀
My stand on this remains, the issue with using an op-amp as an "ideal" I to V has been well known for a long time. I presented a hypothesis, solution, and measured results, but made NO claims about audibility. The EMI/RFI thing is tough to nail down, and I doubt anyone can mount a definitive listening test eliminating all issues but one. I would be happy with at least a good faith attempt to prove that something NEW is present here. To be fair Joe is proposing actual circuits and arrangements of ordinary components, not resistors dipped in secret goop.
BTW it's pretty sad, virtually every pro-shop I enter sells magnetic and copper wrist-bands with paid "testimony" from professional athletes.
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AND...
Good!
That's the goal we are aiming at, as Scott said "full disclosure" - but first we need to present whatever it is, call it what you like, and just let people try it. Then, respectfully, some may think that they are imagining things and then we have a danger of repeating the past. Who wants that? We all look stupid and there will just be people out there who think we are.
Behind the scenes, I have been frantically sending out PMs and pointing out, that as well-meaning they are to me, then please do not defend me. You are one of the Moderators, so I need to look to you, what is the best way and I will do anything you ask. Just give it a go, please.
Re website, that was set up by a well-meaning friend using WordPress, which I cannot fathom. I pretty much forgot about it. I have now made sure that it has been it has been altered for the better. It did say that it was free for DIY and experimenters - I think I can point to my generous DIY credentials over the many years - even to the point where people have described me as generous.
Right now I am very busy in getting information ready over the next week. I am not a little nervous about how this is going to turn out, in fact my stomach is rumbling (my Mother always tells me I was born with a weak stomach).
Also, and I have said this to others, if I had known how crazy this would have turned out, being much wiser now, I would have handled things in an entirely different way. I think every mistake there was to be made has been made.
So I implore you, let's give it a go, we all may have healthy egos, but a step too far and they become unhealthy and it's difficult to see where to draw the line.
Many people here don't even know that we have met each other. I remember sitting right next to you Stuart, in a Malaysian Restaurant in Amsterdam in late 2006 and that we even stayed in the same hotel and so did the late Allen Wright. Next day I went 'walk about' and took this picture below with my trusty Nikon and recall you liked the photo.
Cheers, Joe
PS: Whatever it is, I still hold out hope that this is measurable - it must be - and somebody has even come forward who I have a some faith in and might crack it - then we shall ALL be satisfied.
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The AVCC stage is designed around LT1762, with an added power transistor. So the chip`s datasheet it can reveal quite well how the stage it works. The traces on board it also shows the most of the connections...
I try to understand how can I give separate power supply of 3,3V (or a little bit higher) and 1,2V for Sabre.
Three of the chip`s power rails are coming from the easy identifiable regulators, beside it. The AVCC regulator is a little bit more elaborated and is based on LT1762.
While one can have quite easy access to the three of the chip`s power rails (by disconnecting/removing the old regulators), the AVCC it can not be disconnected, as it is tied to the ES9018 by intern layers traces. To disconnect the DAC chip from AVCC regulator, you should lift up the chip`s AVCC pins.
To modify the AVCC output is quite easy, but what if one it may do this wrong somehow, or an accident it happen, and the chip it get an out of range voltage? Let`s say that AVCC it may be a little bit more tolerant for over voltage, but 1,2v rails are not (by the book)...
I haven`t done it myself this, before I have lifted up the DAC`s AVCC pins... Lifting up the chips pins is quite risky operation too, if it is not done in a particular manner.
After lifting up the pins, it is not advisable to bend it again to resolder it in place. The lifting up it have to be done in only one movement (one direction), then let it so for ever. Any more mechanical tensions applied it will modify the pins section and it will easily broke it right from the base... A (stereo) microscope is very useful for such operations.
So, you know it now. The risks are yours...😉
There is also an alternative to all these above, but you may PM me for that...😉🙂
While one can have quite easy access to the three of the chip`s power rails (by disconnecting/removing the old regulators), the AVCC it can not be disconnected, as it is tied to the ES9018 by intern layers traces. To disconnect the DAC chip from AVCC regulator, you should lift up the chip`s AVCC pins.
To modify the AVCC output is quite easy, but what if one it may do this wrong somehow, or an accident it happen, and the chip it get an out of range voltage? Let`s say that AVCC it may be a little bit more tolerant for over voltage, but 1,2v rails are not (by the book)...
I haven`t done it myself this, before I have lifted up the DAC`s AVCC pins... Lifting up the chips pins is quite risky operation too, if it is not done in a particular manner.
After lifting up the pins, it is not advisable to bend it again to resolder it in place. The lifting up it have to be done in only one movement (one direction), then let it so for ever. Any more mechanical tensions applied it will modify the pins section and it will easily broke it right from the base... A (stereo) microscope is very useful for such operations.
So, you know it now. The risks are yours...😉
There is also an alternative to all these above, but you may PM me for that...😉🙂
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Can the output caps be bypassed? Anyone measured dc without output caps on the balanced xlr outs?
Yes, it can. An usual value of the DC level on outputs (before the AC caps) it may be under 10mV, as right it was marked on the schematic we have seen some posts back. At least, a very fortunate situation is to have almost the same DC level value on both phases of the same balanced output.
You should measure on your own device, because of the production and components tolerances, this value it can differ from a device to another.
For my own, I finally decided to use AC caps on my output module (XLR), in a very right configuration/setup. I`m fully satisfied with this approach so far, and I`m not disturbed any more by the small amount DC on the opamps outputs. I appreciate that the AC caps it however offer a safety/compatibility for connections to an enough wide spectre of amplifier devices or audio systems out there. Oppo`s approach with these AC coupling caps on outputs was/is actually not so bad. The choice of the used components is not very fortunate here...
You should measure on your own device, because of the production and components tolerances, this value it can differ from a device to another.
For my own, I finally decided to use AC caps on my output module (XLR), in a very right configuration/setup. I`m fully satisfied with this approach so far, and I`m not disturbed any more by the small amount DC on the opamps outputs. I appreciate that the AC caps it however offer a safety/compatibility for connections to an enough wide spectre of amplifier devices or audio systems out there. Oppo`s approach with these AC coupling caps on outputs was/is actually not so bad. The choice of the used components is not very fortunate here...
Oppo 105 audio intermittently muted problem. Anybody encountered this problem? Audio will intermittently mute for a couple of seconds and then come back on again. This happened when playing CD and also music files from connected hard disk. When problem initially happened it occurred like once in half an hour. Now it is occurring once every five minutes.
Is there a hard drive in the Oppo 105? Or are you referring to my connected external drive? I believe it is not the case of the connected hard drive as this happens also when I am playing a CD.
No internal drive, so yes, I was referring to the external drive. I have seen them play up. But if it happens on CDs and files, then it sounds like a logic problem.
Go into the Settings and find the Factory Reset and Reset Accounts too. That has fixed up some funnies in the past.
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Oppo 105 audio muting problem.
Dear Joe, I have found out what the problem is. I wrote to the Oppo technical support and they suspected that it was due to handshaking between the Oppo and the TV via the HDMI connection. Since my Sony Bravia 4K TV is an Android based smart TV, it really did not completely turned off even after powering off from the remote control. So there is still communication between the TV and Oppo 105. Each time this happened the audio is muted. Audio muting did not occur after I plugged out the HDMI cable. This however did not solve my problem as it is very inconvenient to plug in and out the cable in the long run. I will have to check with Oppo if there is a fix.
Dear Joe, I have found out what the problem is. I wrote to the Oppo technical support and they suspected that it was due to handshaking between the Oppo and the TV via the HDMI connection. Since my Sony Bravia 4K TV is an Android based smart TV, it really did not completely turned off even after powering off from the remote control. So there is still communication between the TV and Oppo 105. Each time this happened the audio is muted. Audio muting did not occur after I plugged out the HDMI cable. This however did not solve my problem as it is very inconvenient to plug in and out the cable in the long run. I will have to check with Oppo if there is a fix.
New firmware coming out, in fact in beta form now - you may be in luck if that sorts the problem?