Now that's what I was looking for. Much thanks. I will decipher completely tomorrow. If it works with just a chunk out of a doughnut, then the cost of a Tek probe sounds worth the risk.
What I wonder, does not putting basically a big ferrite bead around the lead serve to filter some of what I want to measure?
What I wonder, does not putting basically a big ferrite bead around the lead serve to filter some of what I want to measure?
Some ferrites are intentionally lossy. You want ones that are not, and that have good high-frequency performance in the band of interest.
But I'd just go air-core myself to begin with, or as Thorsten suggested, a small-value resistor with a battery-powered scope.
Despite the link kindly provided, given that money is tight and time is short (for all of us), I really would advise against a home-brew substitute for the Tek electronics. That stuff is expensive for good reasons.
Hi,
1) Stupidly easy if doable - 0.1 Ohm Non Inductive Resistor and Battery Powered 'scope. Velleman used to have some nice ones, but nowadays there are some even cheaper china sourced battery powered pocket 'scopes.
Do watch voltages - some of them lack the insulation of the vellemans, so don't use that trick on 1.5KV HT lines for 211 or 845 Amp's, ok? Be safe.
2) Very easy, bunch on #30 wire on a core, pass the wire through. Example here:
AC Current Probe
Should do if your 'scope has a 1mV/Div setting, if not, add a small battery powered amplifier.
I build one based on folded cascoded 2SK369 and a 9V battery into one of those metal boxes the Yarbo Mains Plug's we use come in. That one has around 30dB gain and a few MHz bandwidth into the 'scope and so extends the 1mV/DIV of our main 'scope to 0.03mV/Div. I use it mainly to snoop around power-supplies and stuff like that, but it is also useful with "sniffer coils".
3) If you are not interested in anything too high frequency you can try MM Cartridges or Cassette Tape heads...
Ciao T
1) Stupidly easy if doable - 0.1 Ohm Non Inductive Resistor and Battery Powered 'scope. Velleman used to have some nice ones, but nowadays there are some even cheaper china sourced battery powered pocket 'scopes.
Do watch voltages - some of them lack the insulation of the vellemans, so don't use that trick on 1.5KV HT lines for 211 or 845 Amp's, ok? Be safe.
2) Very easy, bunch on #30 wire on a core, pass the wire through. Example here:
AC Current Probe
Should do if your 'scope has a 1mV/Div setting, if not, add a small battery powered amplifier.
I build one based on folded cascoded 2SK369 and a 9V battery into one of those metal boxes the Yarbo Mains Plug's we use come in. That one has around 30dB gain and a few MHz bandwidth into the 'scope and so extends the 1mV/DIV of our main 'scope to 0.03mV/Div. I use it mainly to snoop around power-supplies and stuff like that, but it is also useful with "sniffer coils".
3) If you are not interested in anything too high frequency you can try MM Cartridges or Cassette Tape heads...
Ciao T
John
Precisely. 1+
Precision is needed to write scholary articles, for what we are doing seeing the waveform will do nicely.
Ciao T
Precisely. 1+
Precision is needed to write scholary articles, for what we are doing seeing the waveform will do nicely.
Ciao T
@DF96
Thank you for the encouragement.
I meant that wild judgement, without any real knowledge of how something works, has been with me for as long as I owned a modem and since the times of BBS boards, way back in 1988. Public disagreement is no stranger to anyone who has had a public word since then, and I'm certainly no exception.
And while I wouldn't post it for comments, rather as a finished item ready to go, I would certainly like and invite quality comment, even if it may not be right. I would appreciate the effort. NOTHING is that good that it cannot be improved upon.
Unfortunately, to each such comment there will probably be at least ten comments which would not be helpful, but more or less derogatory, one way or another. And after all these years, it gets old. 24 years' old.
I simply have no patience any more for comments like "why didn't you ...", followed by a small schematic perhaps, but with no explanation why would the alternative be better. Then there are those who "know" it cannot work, just by looking at a schematic, and those who "know" that it's below par by definition, because I used output trannies which are not "in" at any moment, and so forth.
A part of the problem is certainly in my own mind; I feel a post addressed to me simply must be answered, any effort on my behalf surely deserves at least that. And that ends up in wild discussions with no real point most of the time.
And lastly, there are the quality comments, by competent people who may simply have a different point of view - well worth at least considering. The minorty by a long shot. Those would be the comments I am looking for, since my one great passion in life is learning. The day I stop learning is the day I start to die, at least, such is my feeling. And the more I know, the more I see how much I have yet to learn, an endless cycle, but it sure is fun.
Anyway, I will have to think about it. But thanks for the support all the same.
Thank you for the encouragement.
I meant that wild judgement, without any real knowledge of how something works, has been with me for as long as I owned a modem and since the times of BBS boards, way back in 1988. Public disagreement is no stranger to anyone who has had a public word since then, and I'm certainly no exception.
And while I wouldn't post it for comments, rather as a finished item ready to go, I would certainly like and invite quality comment, even if it may not be right. I would appreciate the effort. NOTHING is that good that it cannot be improved upon.
Unfortunately, to each such comment there will probably be at least ten comments which would not be helpful, but more or less derogatory, one way or another. And after all these years, it gets old. 24 years' old.
I simply have no patience any more for comments like "why didn't you ...", followed by a small schematic perhaps, but with no explanation why would the alternative be better. Then there are those who "know" it cannot work, just by looking at a schematic, and those who "know" that it's below par by definition, because I used output trannies which are not "in" at any moment, and so forth.
A part of the problem is certainly in my own mind; I feel a post addressed to me simply must be answered, any effort on my behalf surely deserves at least that. And that ends up in wild discussions with no real point most of the time.
And lastly, there are the quality comments, by competent people who may simply have a different point of view - well worth at least considering. The minorty by a long shot. Those would be the comments I am looking for, since my one great passion in life is learning. The day I stop learning is the day I start to die, at least, such is my feeling. And the more I know, the more I see how much I have yet to learn, an endless cycle, but it sure is fun.
Anyway, I will have to think about it. But thanks for the support all the same.
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I must have all intentionally lossy cores. I tried the basic setup Thorsten's link mentioned, and the best effort only just started giving usable output above 200K. I was trying to see the difference in the current going into a driver and why a difference between amps caused a delay in the actual acoustic start of the cone from stop. This is what I am actually trying to get back to. More like 1K was what I was looking for. We all agree, this is not a lab precision problem. Existence of a waveform, and change if I change the circuit is what matters. Knock out the ringing, and you have...... knocked out the ringing.
All out of old tape heads or old cartridges. One of the side effects of moving, one has to clean out the old junk box. I guess the other end of the spectrum from a lossy core would be a steel nut.
No argument why Tek is good stuff. That is why I finally bought a Tek scope a few years back. If I did this for a living, I could not afford not to buy or lease the right stuff. But even back at StoragTek, I had to go borrow a current probe as we did not have one in our lab. Time is cheap if no one is paying you.
Coffee is hot. Later.
All out of old tape heads or old cartridges. One of the side effects of moving, one has to clean out the old junk box. I guess the other end of the spectrum from a lossy core would be a steel nut.
No argument why Tek is good stuff. That is why I finally bought a Tek scope a few years back. If I did this for a living, I could not afford not to buy or lease the right stuff. But even back at StoragTek, I had to go borrow a current probe as we did not have one in our lab. Time is cheap if no one is paying you.
Coffee is hot. Later.
How did you measure the color?
Was it a scientfic test, or just fooling around?
Which spectrometer did you use and why?
How big are the phase shifts of the three prime colors?
Is the wife frowning or clowning?
Is price a painful memory?
Folded foil current shunt is really HF current sensor... a piece of thin copper tape, a piece of PET film from capacitor, two drops of shoe goo, wise to clamp it while goo is drying... voila
P.S. Tek probes are out of league due to HF and DC accuracy simultaneously and it can calibrate itself...
P.S. Tek probes are out of league due to HF and DC accuracy simultaneously and it can calibrate itself...
Progress since 1979?
Back to the thread topic as such, a historical note:
Some years back I took advantage of an offer on back issues of Audio Amateur, and got the complete set. Some were wrapped in plastic, some had rusty staples.
Like so many things, when you have something readily accessible, there's no feeling of urgency getting round to reading it. So these magazines sat in shelves or, when I "downsized", in boxes or cabinets. But recently, running across references to old articles, I've excavated them and started to digest some.
Two things stand out already. One, many of the controversies raging then continue now, and as well the emotional intensities of the protagonists.
Two, the designs presented are often remarkably primitive based on what has become fairly well-accepted practice.
Another attribute is that typographical errors and bad grammar are about as common then as now (with audioXpress), although one is impressed by the sheer volume of material in those days, and immensely grateful to Dell, cohorts, and contributors for keeping the enterprise alive for so long.
It happened that a stack I brought out of storage had exchanges about sound quality versus measurements, very apropos. The allegation that linear distortions accounted for all perceptible differences between two phono preamps (and by extension ALL components), expressed in a letter from Lipshitz, Vanderkooy, and Young (a letter they wanted to withdraw but it was too late) was followed by forum contributions and letters from Jung, Moncrieff, and Curl, and additional articles about subjective/objective stuff. These latter are in TAA 3/1979 and following issues.
In any event, fascinating stuff. In those days I wasn't paying much attention to audio per se, and 1979 marked a milestone as an instrument I'd labored over for some four years was finally on a telescope. It was fun to see that a well-known astronomer, an x-ray specialist, Mike Lampton, was also an audio hobbyist, and with his associate Zukauckas and collaborators contributed a preamp design. The article is one of the better examples of technical clarity, while still having some amusing bits, including the use of solid tantalum caps in the signal path As I say, there has been some progress...
Back to the thread topic as such, a historical note:
Some years back I took advantage of an offer on back issues of Audio Amateur, and got the complete set. Some were wrapped in plastic, some had rusty staples.
Like so many things, when you have something readily accessible, there's no feeling of urgency getting round to reading it. So these magazines sat in shelves or, when I "downsized", in boxes or cabinets. But recently, running across references to old articles, I've excavated them and started to digest some.
Two things stand out already. One, many of the controversies raging then continue now, and as well the emotional intensities of the protagonists.
Two, the designs presented are often remarkably primitive based on what has become fairly well-accepted practice.
Another attribute is that typographical errors and bad grammar are about as common then as now (with audioXpress), although one is impressed by the sheer volume of material in those days, and immensely grateful to Dell, cohorts, and contributors for keeping the enterprise alive for so long.
It happened that a stack I brought out of storage had exchanges about sound quality versus measurements, very apropos. The allegation that linear distortions accounted for all perceptible differences between two phono preamps (and by extension ALL components), expressed in a letter from Lipshitz, Vanderkooy, and Young (a letter they wanted to withdraw but it was too late) was followed by forum contributions and letters from Jung, Moncrieff, and Curl, and additional articles about subjective/objective stuff. These latter are in TAA 3/1979 and following issues.
In any event, fascinating stuff. In those days I wasn't paying much attention to audio per se, and 1979 marked a milestone as an instrument I'd labored over for some four years was finally on a telescope. It was fun to see that a well-known astronomer, an x-ray specialist, Mike Lampton, was also an audio hobbyist, and with his associate Zukauckas and collaborators contributed a preamp design. The article is one of the better examples of technical clarity, while still having some amusing bits, including the use of solid tantalum caps in the signal path
As I say, there has been some progress...What I find to be regrettably different these days in compaison with those days is a loss of drive, loss of impetus to get out there and really do something better. We seem to have lost a kind innocence, if you like, we had in those days. A perhaps foolish and naive concept that we could change something.
And in the end, it was all just a business to some, and we took too long to understand this.
The audio market was first hit hard by the appearance of the video tape market - a new toy which drew money away from audio. But the advent of the PC was what killed the audio of old, it barely survived that, at least some, while others did not (such as Sansui, Akai, JVC and a slew of others).
And what is left of it today is pitiful compared to those pioneering times. These are the days of whiyy kids, hit-and-run companies all geared to making a fast buck.
Whoever doesn't see that the audio as we knew it is in its last days is either unwillig to see it, or has a hard problem. We have turned into a cheapskate civilization, in which price is EVERYTHING. Everybody wants it all for virtually free.
As affictionaods, we cried out for 15+ years that 16-bit just wasn't enough, and when they decided to go 24-bit, here comes MP3 in its essentially 4-bit format. It's easy, it's accesible via the Internet (i.e. from home) and it's free. Never mind that it has been effectively stolen, we want it.
The old system had its faults, but worse, it decided not to change, thus signing its own death warrant. Too many middlemen, too many price hikes, too much control in the hands of too few. It didn't stand a chance in a fast moving world.
So it was torn down, but that's not the problem, as I see it the problem is while we have torn it down, we have NOT replaced it with a different set of values. Nobody really knows how the game is played today, it's all rather chaotic.
Yet, one thing seems obvious (to me, at least) - we are about to witness the audophile's worst nightmare, seeing his beloved hobby being turned into just one more VLSI inside a tablet. The end of audio as we have known it.
And in the end, it was all just a business to some, and we took too long to understand this.
The audio market was first hit hard by the appearance of the video tape market - a new toy which drew money away from audio. But the advent of the PC was what killed the audio of old, it barely survived that, at least some, while others did not (such as Sansui, Akai, JVC and a slew of others).
And what is left of it today is pitiful compared to those pioneering times. These are the days of whiyy kids, hit-and-run companies all geared to making a fast buck.
Whoever doesn't see that the audio as we knew it is in its last days is either unwillig to see it, or has a hard problem. We have turned into a cheapskate civilization, in which price is EVERYTHING. Everybody wants it all for virtually free.
As affictionaods, we cried out for 15+ years that 16-bit just wasn't enough, and when they decided to go 24-bit, here comes MP3 in its essentially 4-bit format. It's easy, it's accesible via the Internet (i.e. from home) and it's free. Never mind that it has been effectively stolen, we want it.
The old system had its faults, but worse, it decided not to change, thus signing its own death warrant. Too many middlemen, too many price hikes, too much control in the hands of too few. It didn't stand a chance in a fast moving world.
So it was torn down, but that's not the problem, as I see it the problem is while we have torn it down, we have NOT replaced it with a different set of values. Nobody really knows how the game is played today, it's all rather chaotic.
Yet, one thing seems obvious (to me, at least) - we are about to witness the audophile's worst nightmare, seeing his beloved hobby being turned into just one more VLSI inside a tablet. The end of audio as we have known it.
I fully agree with you. Yet, there are many out there that still 'go out and really do something better'.
I try to capture that, twice per year, in my Linear Audio bookzines.
Sure, there's not enough to support a multi-10k-copies monthly, and Linear Audio doesn't make any money.
But the interest is there, and the very high level of designs and analysis is there as well, you just have to look for it.
jan
Disclosure: I am the editor & publisher of Linear Audio
Not wanting to derail the current direction of the thread and drag it back to where it was a few weeks ago, but I found the part of the conversation discussing different design techniques and topologies for power amps quite interesting, particularly different approaches to feedback like high open loop gain with high total loop feedback vs local degeneration with lower open loop gain and feedback etc... and the seeming inadequacy of "conventional" measurements like THD to describe whether an amplifier sounds good or bad...
I have to admit that in years gone by I've been a bit of a sceptic about one amplifier that "measures well" sounding any different from another amplifier that also "measures well", (given how small the measurement differences between good amplifiers are, compared to the huge differences in measurements between one speaker design and another) but I now have to admit that I have heard amplifiers that sound significantly better than many others yet don't measure particularly different, at least in terms of frequency response and distortion.
(I'm aware that there are certainly more advanced measurements than this that can be taken, but not being an amplifier designer myself I don't know what they might be, and which might correspond to perceived quality, which I guess is the whole point of this thread...)
Out of curiosity I've attached the schematic of an amplifier that I particularly like the sound of, which measures well with conventional measurements but I find sounds significantly better than many other similar spec amplifiers I've heard, and I'm quite interested in any comments from the likes of Wavebourn and ThorstenL on (a) whether they think the design is good or bad in their opinion and (b) whether its just a typical by the numbers "textbook" design or whether there is anything clever/unique/novel about it that might account for a subjectively pleasing result. (or is it all just in my head )
Extra points for recognising/guessing what brand/model it is
I have to admit that in years gone by I've been a bit of a sceptic about one amplifier that "measures well" sounding any different from another amplifier that also "measures well", (given how small the measurement differences between good amplifiers are, compared to the huge differences in measurements between one speaker design and another) but I now have to admit that I have heard amplifiers that sound significantly better than many others yet don't measure particularly different, at least in terms of frequency response and distortion.
(I'm aware that there are certainly more advanced measurements than this that can be taken, but not being an amplifier designer myself I don't know what they might be, and which might correspond to perceived quality, which I guess is the whole point of this thread...)
Out of curiosity I've attached the schematic of an amplifier that I particularly like the sound of, which measures well with conventional measurements but I find sounds significantly better than many other similar spec amplifiers I've heard, and I'm quite interested in any comments from the likes of Wavebourn and ThorstenL on (a) whether they think the design is good or bad in their opinion and (b) whether its just a typical by the numbers "textbook" design or whether there is anything clever/unique/novel about it that might account for a subjectively pleasing result. (or is it all just in my head
)Extra points for recognising/guessing what brand/model it is
Attachments
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Bcarso, good for you in looking at the articles and controversy in TAA in the late 70's. Please remember that in those days, home computers were crude, and we hand typed our LTE's and submitted them by mail. One important person who you might unfortunately overlook, is Dr. Rod Rees and his articles of listening tests. Please check him out.
... Extra points for recognising/guessing what brand/model it is
Aaaa, ... that'd be some kind of Luxman, boss.
Let me just add that as far as I am aware:
1.NONE of the controversies and/or questions raised then have been resolved to this day, althoug some have been greatly clarified since those days, and
2. Not many - indeed, if any - siginificant and crucial new questions have been raised, and those that have, are mostly variations to those "old" themes.
Which to me clearly shows that THOSE were the days of true innovation, while these are the days of mostly compliance to marketing laws.
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