Christer, I hope that I can learn more from you. I also hope that you can learn to 'trust your feelings' on some things. This can be important as well, especially in medicine and in audio.
Hi,
And still figuring out where the coupling caps should go, right?😀
John C.,
It would be absolutely great to have these measurements done by both yourself and Bruno Putzeys.
You're a sport to accept the offer.
Cheers,😉
And still figuring out where the coupling caps should go, right?😀
John C.,
It would be absolutely great to have these measurements done by both yourself and Bruno Putzeys.
You're a sport to accept the offer.
Cheers,😉
Frank, I misread what SE wanted. I still don't have in front of me, his original offer, but sure, I will try it. I will use slightly different frequency and level, because of my test equipment. As SE says, my test analyzer is getting old. I had it calibrated about 10 years ago, but still, even with the board swap that ST did, they used a rebuilt board, and the aluminum electrolytic caps seem to be going bad. You would not think it, but it's true. I have replaced some of the caps and the unit has sprung back to life, after refusing to null at ANY frequency. I could go into it and change almost everything, but it just isn't worth it, at the moment. Now, I use about 70mV and a 5KHz sine wave.
I admit that I am working at the 'hairy edge' of my primary test equipment, but I still get results. What is interesting to me as well, is the amount of garbage in the air above 20KHz. Now that I think about it, this might be why Bruno has so little 'garbage' in his graphs. These days, working with a 50K bandwidth FFT, I get plenty of extra stuff. Getting beyond this might be worth rebuilding my ST1700B.
By the way, I hope to get the schematics for the AP analyzers soon. I'm sure that I will learn a thing or two. Still, the shorted input noise of my modified 1700B is probably quieter than the AP, according to its specification. This is because I modified the input stage with quieter IC's.
I admit that I am working at the 'hairy edge' of my primary test equipment, but I still get results. What is interesting to me as well, is the amount of garbage in the air above 20KHz. Now that I think about it, this might be why Bruno has so little 'garbage' in his graphs. These days, working with a 50K bandwidth FFT, I get plenty of extra stuff. Getting beyond this might be worth rebuilding my ST1700B.
By the way, I hope to get the schematics for the AP analyzers soon. I'm sure that I will learn a thing or two. Still, the shorted input noise of my modified 1700B is probably quieter than the AP, according to its specification. This is because I modified the input stage with quieter IC's.
Hi John,
Rest assured, I trust you and your results as they were cross checked at the Leuven University by Dr. De Ceuninck on my (customer request) and A.J. vdH's request.
At the university Dr. DC has incredible resources to examine anything we put forward and he'd perform any test we thought worthwhile within "scientific" reason.
For the moment at least, RF disturbances in Europe don't seem to be as bad as in the U.S. but, as usual, whatever goes on with you guys now, we're sure to experience it in the years to come.
Regarding your measurement equipment and your results, yes, the caps may have played a major role but I trust you repeated the tests often enough to feel confident.
As said, your results were confirmed, probably without feedback to you but that's how it goes sometimes.
Incidentally, when you say you did those measurements about ten years ago that's also about the same time I first learned about this although I can't remember how or when....
Was it a conversation with A.J.vdH? An article somewhere?
Did you perhaps publicise your results somewhere? I just can't put my finger on it.
Feel free to contact me whenever you like by mail.
Cheers,😉
Rest assured, I trust you and your results as they were cross checked at the Leuven University by Dr. De Ceuninck on my (customer request) and A.J. vdH's request.
At the university Dr. DC has incredible resources to examine anything we put forward and he'd perform any test we thought worthwhile within "scientific" reason.
For the moment at least, RF disturbances in Europe don't seem to be as bad as in the U.S. but, as usual, whatever goes on with you guys now, we're sure to experience it in the years to come.
Regarding your measurement equipment and your results, yes, the caps may have played a major role but I trust you repeated the tests often enough to feel confident.
As said, your results were confirmed, probably without feedback to you but that's how it goes sometimes.
Incidentally, when you say you did those measurements about ten years ago that's also about the same time I first learned about this although I can't remember how or when....
Was it a conversation with A.J.vdH? An article somewhere?
Did you perhaps publicise your results somewhere? I just can't put my finger on it.
Feel free to contact me whenever you like by mail.
Cheers,😉
john curl said:
Here's my original offer on AA:
http://www.audioasylum.com/forums/prophead/messages/6876.html
And here's where I reiterated it here on diyAudio.com:
http://www.diyaudio.com/forums/showthread.php?postid=274115#post274115
And I re-re-re-reiterated it since.
Why? You were clearly showing distortion at 1kHz, 30mV as evidenced by your Mac The Scope plots.
So you're no longer getting results at 30mV, 1kHz?
How could you reach the conclusions you did regarding your measurements with everything seeming to be veering all over the road like this?
You've said the cables have measured differently over time and now you're saying your 1700B is giving different results over time. And yet you say that nothing so far has given you any reason to suspect that there may be something weird going on with your equipment?
But the only "garbage" in your Mac The Scope plots was the 15.75kHz spike.
In any case, if you want to measure at 70mV, 5kHz, that's fine as long as the magnitude and frequency are agreed to in advance so that Bruno can measure at the same magnitude and frequency.
And by the way, would it be too much to ask for you to EMail me your home address to send the cables to? UPS won't deliver to PO boxes and I don't want to be here two weeks from now with your saying that the cables haven't arrived with no way of verifying it.
se
fdegrove said:
Then perhaps you'd care to detail the equipment, methodology, and test conditions used for this cross checking.
Also, does this Dr. De Ceuninick have a first name?
se
Hi,
I told you already that I wouldn't, didn't I?
The same resources are availble to anyone caring to foot the bill so why you even think I, or anyone else would provide for a free lunch is beyond me.
Cheers,😉
I told you already that I wouldn't, didn't I?
The same resources are availble to anyone caring to foot the bill so why you even think I, or anyone else would provide for a free lunch is beyond me.
Cheers,😉
fdegrove said:
Excuse me? How is detailing the equipment, methodology and test conditions of measurements you say cross check John's measurements providing a free lunch?
If you're not going to provide this information, then mentioning it can serve no useful purpose.
se
For all that I type, SE you sure don't learn much. I HAVE changed my parameters BECAUSE my test equipment is happier at this level and frequency. What's it to you?
"What's it to you?"
I'm going to take a wild guess and say... scientific method? Try a google search:
www.google.com
I'm going to take a wild guess and say... scientific method? Try a google search:
www.google.com
Hi,
Of course....What's that to do with anything or are you going by titles?
In which case you can call me doctor honoris frauda.
Cheers,😉
Of course....What's that to do with anything or are you going by titles?
In which case you can call me doctor honoris frauda.
Cheers,😉
john curl said:
How are you gauging your equipment's "happiness"? By the amount of distortion you're getting? If so, how do you know you're getting more distortion because you're equipment's happier or because it's more stressed?
Oh, and I forogt something from your previous post:
There is no "shorted input noise" equivalent spec for the System Two Cascade.
The -112dB spec that you cited on AA for the AP spec is the SYSTEM'S residnal THD+N spec at 1kHz.
In other words, that -112dB spec includes the generator, notch filter and analyzer.
So how on earth do you figure that your 1700B is quieter?
Also, since you're just using your 1700B as a signal generator, notch filter, amplifier, what "input" are you shorting? If you're shorting the input to the notch filter and amplifier, then your signal generator's not even included.
So, instead of comparing apples and oranges, show us that your SYSTEM'S residual THD+N is better than the AP's. Which would be -112dB or 0.00025%.
se
fdegrove said:
Because if I had his first name, I could look him up and ask him for some details of the measurements you said he did to cross check John's measurements.
se
Page 12 of 41 page spec sheet on AP Cascade.
Residual noise 80kHz BW -111.8 DBV Mine is about -115dBV.
Residual noise 80kHz BW -111.8 DBV Mine is about -115dBV.
Frank, are you telling us that someone else measured this distortion in wires?
I know that VDH did, years ago, but I have been out of contact with him over the years. I wish he would give me some input at this point. Frank, once you, or any one else are set up, it should be fairly easy to measure this distortion. It is just that it lies just below virtually any single function analyzer. I use two series analyzers, Cyril Bateman uses his own homemade notch filter and a pretty good A-D with a PC to get his results. The cascade has both a linear notch filter and then a FFT section that does essentially what the combination of my two units does, but they have a much better notch and a damn good oscillator. I work around this by IGNORING the notch and the first 2 harmonics (2'nd and 3'rd) These can also change but not by much. My interest is in the 5,6,7,8,9 harmonics mainly. I pretty much ignore everything else. I am still getting results, but I don't think that I have heard the last from SE on this, and I doubt that you will either. Talk about taking it personally. ;-)
I know that VDH did, years ago, but I have been out of contact with him over the years. I wish he would give me some input at this point. Frank, once you, or any one else are set up, it should be fairly easy to measure this distortion. It is just that it lies just below virtually any single function analyzer. I use two series analyzers, Cyril Bateman uses his own homemade notch filter and a pretty good A-D with a PC to get his results. The cascade has both a linear notch filter and then a FFT section that does essentially what the combination of my two units does, but they have a much better notch and a damn good oscillator. I work around this by IGNORING the notch and the first 2 harmonics (2'nd and 3'rd) These can also change but not by much. My interest is in the 5,6,7,8,9 harmonics mainly. I pretty much ignore everything else. I am still getting results, but I don't think that I have heard the last from SE on this, and I doubt that you will either. Talk about taking it personally. ;-)
john curl said:
Well, Bruno's an "any one else." Yet nothing's turned up.
Then by all rights it should be showing the same sort of distortion you're measuring if the distortion you're measuring is being produced by the cables. But it's not. And the plots speak for themselves; they're clearly measuring well below where you are.
But John, if the distortion you're measuring is being produced by your 1700B, why would you expect anything other than to still be getting "results"?
Why do you seem to think that getting the same results using the same equipment is some sort of indication that there's nothing wrong with the equipment?
se
john curl said:
Oh for crying out loud.
John, that's the spec for the System Two Cascade's ANALOG ANALYZER. That's just used for simple stuff THD+N measurements.
Bruno did his measurements using the System Two Cascade's DIGITAL ANALYZER (didn't you notice that they were FFT plots?). The System Two Cascade's analog analyzer wasn't even in the picture.
You're completely overlooking the bottom line here, John. The bottom line is the fact that in your plots, your noise floor is bottomed out at around -125dB relative to the 30mV fundamental. In Bruno's plots, it's around -145dB relative to the 30mV fundamental.
Even with the simple power averaged plots, it's at -130dB relative to the 30mV fundamental. 5dB below your -125dB.
Your plots represent all the accumulative noise in your system and Bruno's plots represent all the accumulative noise in the System Two Cascade. And the System Two Cascade wins hands down.
se
john curl said:
John, I get the impression you understood my post in the right
way, and didn't get too annoyed by it. I am happy to see that,
since I don't want you to leave the forum - I think we have a
lot to learn from you.
Actually, for empirical reasearch, you won't learn that much
from me, I am a theoretician, not an experimentalist (I have
once worked as a digital electronic designer though, so I have
also practical engineering experience). There are
others on the forum who work professionally with empirical
research and know about how to set up experiments, do
the statistics etc. etc. Better ask them or read a book or two.
Now, I am not really asking you to do valid scientific research,
just to be aware of the effort it takes to establish truth rather
than just some measurements.
You see I do trust my feelings in many cases, but I don't claim
them as truth since I know I may be wrong and may even
change my mind in the future. Medicine is a good example.
I have had quite serious health problems for many years
(nothing that will kill me and I hope to recover completely
although it seems to take for ages) so I have really looked
around for alternative treatments to try speeding the process.
I don't jump on to anything I see, but sometimes I read about
something that seems trustworthy enough to try further.
One thing I did try, although not quite for these health problems,
was the Tomatis listening therapy (or training as they call it
to not make any medical claims). I read two of his books and
all I could find on the internet before deciding to give it a try,
and yes, I do believe in this. I am not sure all the effects I
experience are real, but I am convinced some of them are.
I sometimes tell people about this, often enthusiastically,
and have done so once or twice on this forum without it getting
much attention, but I am always careful to point out that
it is my experiences and there is no scientific proofs that his
method works and that anybody who might get interested
should read up and form their own opinion before trying it.
BTW, finally, more than 50 years after Tomatis started his work and private research on human hearing, some
scientific studies are starting to emerge. One recent study at a
swedish hospital concluded the method was effective for the
purpose they tried it for. There are even more interesting,
yet unpublished, results from hospitals in other countries.
So, even though Tomatis was ridiculed for many of his claims back
in the 50's, some of them may eventually turn out true. In fact,
some of them were found to be true already in the early 60s.
Maybe it will be same thing with cable distorsion and other
stuff, we cannot know today.
To be somewhat more constructive, I don't know, maybe audio
designers tend to isolate themselves from each other for
competition or other reasons, but maybe you know other
people with good test equipment and whom you trust, who
could try to repeat your experiments? You live in Berkeley,
maybe you could try getting sombody at UC Berkeley (EE,
physics ?) interested in the topic, although I know it is often
difficult to get the attention of university researchers. We are
usually too busy with our own reseach and teaching, have
to publish, apply for money etc. etc. Still, maybe you know
somebody, who knows somebody... Sometimes they do get
interested in things with practical interest. There are people
at the physics dept. at my university who study the limitations
of resolution for AD converters, for instance, trying to figure out
what the physical limitations are and it one can get around them.
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