Wavebourn, can you play somewhere else? Either you explain in more detail, or just leave off, because you are not being productive.
bear said:
It is an issue of high frequency interference. RF, cell phone GSM gateways. I am referring to an image shown here:
http://www.diyaudio.com/forums/showthread.php?postid=810164#post810164
🙁Wavebourn said:
It would be difficult if not impossible to separate grounding and bypassing issues in this case. The front transistor is bootstrapped and in virtual stasis for any load. Increased distortion with load, in my experience, has always been traced to residual supply/ground modulation. That is playing with star grounding, for instance, of bypass leads moves the spurs around.
There is the additional item that again I see no evidence of the audibility of any distortion at the -108 vs -105 dB level (Lamm?).
John, you should also give PMA some slack here. The RFI incursion stuff is very important. At least one high end interconnect is just repackaged Tektronics RFI resistant technology.
john curl said:
Come on, John... Everyone who was productive in the lab studying semiconductor electronics' basics understands how obvious it is...
scott wurcer said:
Yeah that's low, but how much distortion does a ceramic cap cause? I don't know. Most people seem to agree that that they audibly degrade sound quality. Doesn't the quality of distortion matter? I think it matters very much.
Scott, please address Wavebourn, completely and clearly, because it is your IC that is being discussed. Please supply as much input as it takes to make Wavebourn's 'obvious' more obvious to the rest of us, or at least gets him off the thread, as he has now put himself in the way of other discussion.
It is not the RFI problem that I am trying to avoid, it is the TIMING of the question. It came completely out of 'left field'.
It is not the RFI problem that I am trying to avoid, it is the TIMING of the question. It came completely out of 'left field'.
john curl said:
John
I fully agree, and think that this is one of the most important issues when talking about audio design
Wavebourn said:
Wavebourn
I don’t follow you all the way home on this one, and the explanation you have given so far doesn’t make it any clearer. So instead of a short reply like “it’s obvious” and “everybody knows” could you please do a more deep and understandable technical explanation?
You might be right so I don’t condemn you thought, but would like to examine it.
)
Johnloudb said:
All distortions add up.
So all distortion matters in the total picture.
- We have level ...
- We have sort of distortion, quality
Does this MATTER?
In what sense? .... is my 'answer'.
If you mean any low level dist matter in some sense .. Yeeees!
If you mean does it matter to your ears ..
we have to take into accpount what one ear is capable of to hear.
This makes it difficult, if not impossible to answer : If it matters
It is better to re-put the original question into:
- How big a level of this or that type of distortion quality
- does it take, before it MATTERS to my heearning apparatus
- and so my mind can notice the difference with/without.
If we ask too much of a general question
the answer will probably be not very detailed or accurate
.. as the question, in itself lacks good meaning.
We can say:
Some questions are not fruitful or Even sensible, if we want a good answer
🙂 Regards to John (Jenving is OK) Curl and all nice in here.
The rest can go do something else. elsewhere or stay silent.
Line 'linie' Lineup 😎 Matters he? In what sense do you mean?
john curl said:
So did I, but I prefer to get -148dB from a good quality ceramic cap. You can too, if you try.
john curl said:
"Scott, fight back".
No John, it was not about Scott's IC, and nothing personal. It is about how emitter followers work. I suggest you to figure out, what do you want to see in this thread: either thorough analysis of subtle processes causing distortions, or silly games around obvious things. It's hard to guess each and every time what kind of game are you playing in the certain message at each particular moment. You change rules very often.
I am out of this thread. Forever.
Do you think that the cap used in the circuit that Demian has used a .1 npo cap? DEMIAN, please respond.
Here is the circuit diagram for the demo board in question ESS SABRE 9012 Demo board schematic
The circuit calls out 2 .1 caps to ground (my mistake, its more serious than I thought) on pg 1 U2. all of the components are really low value. the size is approx 2mmX4mm. The sample NPO's I have are easily 10X that.
And here is a picture of the board in question:
The circuit calls out 2 .1 caps to ground (my mistake, its more serious than I thought) on pg 1 U2. all of the components are really low value. the size is approx 2mmX4mm. The sample NPO's I have are easily 10X that.
And here is a picture of the board in question:
Attachments
I think RFI is a serious issue that degrades everything, but the fixes don't necessarily improve things.
As to 'reverse isolation' its a big problem for precision frequency control. Here is a novel circuit for serious out to in isolation: Low Phase Noise Amp
Look at the discrete circuits at the bottom of the page. They have as much as 160 dB reverse isolation if built properly. Needless to say layout matters.
As to 'reverse isolation' its a big problem for precision frequency control. Here is a novel circuit for serious out to in isolation: Low Phase Noise Amp
Look at the discrete circuits at the bottom of the page. They have as much as 160 dB reverse isolation if built properly. Needless to say layout matters.
Wavebourn said:
Wavebourn
If this is all that you can come up with, to answer a few relevant questions to your previous posts, well then I’m not impressed.
john curl said:
Yes, there's lots of things to try.
Getting my distortion analyser software working right now.lineup said:
I agree with you, and that is like the big question that hounds everyone: What is and isn't audible?
And the only one who knows that answer is Charles Hansen who did extended listening blind testing. In which case everything including switches are audible.
http://www.diyaudio.com/forums/showthread.php?postid=1771831#post1771831
Kudos to him for doing such a test, and sharing it. Personaly, I'd like to see more of this type of testing. I'd like to try this kind of test as well, but I've got lots of stuff to do right now. It's unlikely anyone would believe the results of any test I did anyway.
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