Bogdan, your question is real, but incomplete. What REALLY makes a lot of regulators 'fail' sonically is if they ring, with a changing current output. It might be 'possible' to determine that from the curves given, but not easily. I am going to put up the last page of a PhD thesis, a part of which was published in 1966, in the IEEE. There is the math for what you are asking, however nobody here takes it seriously, except somebody like me.
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Richard, serious manufacturers have to work under a standard. In Europe this is usually EN61558 and it is very detailed.
As usually, it specifies the minimum acceptable. So you can see two trafos bearing compliance to the same std and class ect and one has the thickest laminations accepted for the specified temp rise and the other has thinner (and runs cooler under the same load).
Now, load regulation is an important electrical parameter. But as Demian wrote, a low number there, does not provide for minimisation of external fields. It is what one is asking for.
Martin, when you order a lot of trafos, you can arrange for extra winding with the manufacturer. Me and the rest, can not.
What I do? I go for a trafo with a higher secondary voltage and I wind extra primary turns myself.
Or I buy two trafos with double the secondary voltage and I wire their primaries in series.
George
EN61558
IEC60555
CISPR 11
I know about these things. i am not trying to teach anything but stating a useful parameter that a lay person in DIYAUDIO might use so they can get what they think they should be getting.
Everyone knows what Demian said except the novice. This is otherwise, not news. In my context... not anothers... flat toped waveforms are usually the result of using the transformer at too high of a load... but one may assume it would not do that if jusdged by its (marketing) rating.
Standards do exist and mfr may or may not decide to use them for a particular market. The IEEE standards here are tested to complience by UL and other independant testing labs. Unless they are absolutely manditory by a country code or similar.
many DIY'ers buy from catalogs which import from countries that are not going by your standard. The trend is to buy more and more around retail and direct from factories..... expecially from Asia region. Catalogs and Internet info is often sketchy -- usually giving ony V and A or Va and a few other things like dual volatge input or weight and physical size.
The type of construction and the loading on the transformers of course affect leakage numbers and temp rise and field size. the question I keep asking is what are the ideas to handle these issues in an audio settting. I have my solutions... what are yours?/others? Asking for this should not imply I dont have a clue. [though it might
] Now adding more windings gets you where you need to be under your load. But the easier route for most people is to ask and obtain the transformer with better load regulation... You can also order a tranfo that is a higher current rated transformer and/or with larger core and get similar results. ... which would give you a better load/volt regulation. This is especially important as the power/current requirments go up from low and steady - a le preamp - to power and with its highly changing current requirements.
Thx-RNMarsh
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Even worse, you can get a patent on something that had previously been patented.
Ray Kimber managed to secure a patent for a simple quad braided cable which had previously been patented back in the late 50's and is still being sold today by Magnetic Shield Corp. as their "Inter-8 Weave." Hope he got his money back from his patent attorneys.
se
Steve Eddy,
I would suspect that though the patent should be invalid Kimber is still threatening anyone else who tries to copy his wire configuration. I think you are taking about the 4TC and the 8TC wires he sell. I have some but they were gifted to me. There isn't anything wrong with them until you have to pay the price they sell for! I think I have a pair that even had silver wire, but I don't think I can hear any difference between copper and silver, again I didn't pay for them so why not keep them...... I will say that I hated the spade ends that they used though, very hard to tighten up on so I cut one leg off so I could get them into my binding posts.
I would suspect that though the patent should be invalid Kimber is still threatening anyone else who tries to copy his wire configuration. I think you are taking about the 4TC and the 8TC wires he sell. I have some but they were gifted to me. There isn't anything wrong with them until you have to pay the price they sell for! I think I have a pair that even had silver wire, but I don't think I can hear any difference between copper and silver, again I didn't pay for them so why not keep them...... I will say that I hated the spade ends that they used though, very hard to tighten up on so I cut one leg off so I could get them into my binding posts.
If you're finally taking Dick Greiner and his students seriously, I'm delighted at the news. He's one of the great minds in audio engineering. I was privileged to spend an afternoon with him when he was still at UW (he was evaluating one of our inventions). A real gentleman, even if he disagreed with you (he liked our invention, btw).
Daugherty and Greiner's classic paper contains errors an misinterpretations widely discussed in textbooks, over the years. For a short summary, see Slew-TID under "TID".
Could be, getting an invalidating judgement can cost you several million dollars in legal fees. Make sure though that they are paying their maintainance fees on an essentially useless patent, there is a code on some of the search engines for patents that have expired for lack of maintainance fees.
Naah. Actually I was the one who broke the news to him. He took it well and said he wouldn't enforce the patent.
I believe so, as well as their HERO interconnects. The "technology" was referred to as "Orthogonal GyroQuadratic." Nine syllables to describe a four stand braid. Gotta love marketing-speak.
se
The USPTO is way overloaded. Its a wonder the quality is what it is. The examiners have maybe 2 hours to read and evaluate a patent, and another hour to deal with the response when you push back on the rejection. They are always rejected on the first submission.
Sometimes they are really good at finding prior art. I got zinged on a connector when the examiner sent a patent from 1925 that was very close. No search engine would have found it. Other times they are really thickheaded and you just give up.
Sometimes they are really good at finding prior art. I got zinged on a connector when the examiner sent a patent from 1925 that was very close. No search engine would have found it. Other times they are really thickheaded and you just give up.
John, yes, it is a key issue for achieving good sound, although is not laying at surface still. PSSR mechanisms actually suffer from the same: unwanted ringing, that destroys micro-level signals. Christoph Schurmann, the SOULUTION designer, seems to catch the seed. Look at his measurements:
One should also remember, that micro level ringing depends not only on reg schematics and simulations, it is also wiring and all other aspects.
To me, the best thing, for a given stage PS, is a shunt type, located just near the stage.
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Power transformers
The truth is that they are a vanishing component. Between power factor requirements and efficiency requirements the traditional transformer-rectifier supply has a dim future. Investing time in making a good audio grade switcher would have a much higher long term return. And a bigger challenge.
The truth is that they are a vanishing component. Between power factor requirements and efficiency requirements the traditional transformer-rectifier supply has a dim future. Investing time in making a good audio grade switcher would have a much higher long term return. And a bigger challenge.
Richard
I tried to warn Ed that this assumption may lead him to wrong conclusions. I hope I haven’t offended you.
But the easier route for most people is to ask and obtain the transformer with better load regulation... You can also order a tranfo that is a higher current rated transformer and/or with larger core and get similar results. ... which would give you a better load/volt regulation.
Thx-RNMarsh[/QUOTE]
Load regulation is primarily governed by the size (power rating).
http://www.emcod.com/images/load_reg_chart.gif
For a given size trafo, low copper losses and working close to core saturation achieve good (low) load regulation. For EI units, the more filled is the winding window, the better.
For this target, one could also consider a ferroresonant construction
I understand although I am novice.
George
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Thanks for the link. The analysis of max slew rates in signals is somewhat problematic- for a properly designed digital source, I can't disagree, but for the currently fashionable (in certain niches) NOS systems and certainly for phono, they fail to take into account the noise inherent in those sources (especially ticks, pops, and mistracking). A small transient event can affect in band (audible) performance. (In RC-coupled circuits, this can also manifest as blocking, an even worse problem)
It is interesting, however, to see how people were feeling their way around back in the '60s and '70s as well as how quickly these issues were put to rest (other than in fashion audio gimmickry).
A re-examination is cheaper, though still not cheap.
IME, patent examiners almost never look at prior art outside the patent literature. This just makes more work (and more BMWs) for lawyers, which is probably the intention.
It may be simpler than that: just normal human 'blindness'. If you work in patents, you will probably assume that patents are such a good thing that it is inconceivable that anybody would have a bright idea and not patent it. Therefore there is no point in looking elsewhere.SY said:
Most professions make some version of this assumption. That is why doctors can get upset when their patients Google their symptoms, or economists get upset when physicists point out the glaring holes in their assumptions about markets. Lawyers are the best at it, as they have managed to enshrine part of this assumption in law. If only physicists could do the same with Nature: we could then insist that engineers had to get their calculations done by a registered physicist.
George,
I will run level vs. distortion curves today, using a resistive load.
There is a bit of difference in the core sizes among the E-I core types from the same manufacturer depending on their market.
I am used to transformers being rated for 110/220 V at 50-60 Hz. I use them at 125 volts 60 Hz. Your experience is (If I have it correctly) 240 volts at 50 Hz. So it seems reasonable you have found adding 10% extra turns is useful. I would be using the transformer at 94.7% of maximum rated flux, you would be using such a transformer at 109.1% !!
Dick,
Once I finish on transformers, I will get to rectification and the noise in that process. For reducing line noise, I am familiar with; capacitors across the AC line, resonators across the AC, capacitors across the secondary, inverted dual secondaries, bifilar chokes, common mode coupled coils with one of them shorted (Patent US5969583 - Common-mode EMI filter with a separately wound ground winding - Google Patents) and the one I like most using a neutralization winding. The last method also allows one to offset the "DC" on the incoming power line.
Of course the other issue is load rating. As the transformers are rated for in this case about 30 VA and are driving a rectifier. There is derating required. About 90% for using just two diodes and logically 45% for a full wave bridge would be the maximum load. As the circuit under power can vary in power draw, the supply current rating should be 20% greater than the draw at a decent minimum. In a power amplifier the maximum power is required infrequently except for Class A amplifiers.
Scott,
The solution to the preamp was to :
Add power up order diodes, add 470 uf to each rail, add ceramic bypass caps, change the 1M servo output R to 500K and add a capacitor case to ground plane. I would be curious about your method to prevent latch-up.
Additional improvements can be had by using a two stage gain topology. The first stage is fixed at 10-20 dB so maximum CMMR & PSSR can be seen. The second stage would be the variable gain stage. Of course the circuit screams for an output buffer. For real tweaks the first gain stage can be made of paralleled op-amps to get even lower noise! The maximum would be to use a center tapped input transformer and two gain chains, one push the other pull.
ES
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That's fine the order was the issue, in high gain circuits usually with some inductive or highish resistance source the wrong one first and the Ib times R was greater than the railed output/gain.
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