In the case, you can not say anything. So tell me, what is a strong grass acting grow and smoke in the pampas? You have mixed everything that you can. I'm from Russia not Italy, and it's not at all close. Although in spirit and design, it seems that our views are close. Litz, I just assumed that it would probably be better, like a silver wire and only on very large magnetic cores and necessarily with low specific losses of W / kg in the type of amorphous and nanocrystalline. I'm sure on such core, and perhaps even more on toroidal, Litz will show a much better effect. I completely interpreted the late author, and by the way, it is possible for Popilin to discover this, but all the transformers work the same way around the world, even though the power is at least a weekend. US engineers laughed terribly at people like you and Partridge when in studio and not in home appliances they did everything the other way around and got a professional result. Apparently they also know how the transformer actually works.
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The V51 core has about 23.5-24 cm average turn length depending on how much of the available height one uses. 24 cm is really full!
In my experience the numbers in the database are correct, and a reliable source to do the calculations. At least I am seldom more than 2% off when using database numbers and resistance tables of copper magnet wire.
Your suggestion of 4% more resistance because of wire tension/stretching is pure nonsense 🙄. With normal winding tension the stretching is about zero.
My conclusion is that Walter's primary litz wire must be the equivalent of 0,31 mm diameter (so not 0,31 mm²) copper wire.
When using the available winding space for normal magnet wire he could have used at least 0,4 mm diameter and have a primary DCR of some 58 ohm with the same number of turns, quite a bit less than the 92 ohm of the litz wire.
For audio applications, you probably do not need litz with very thin component wires. It is enough not more than 4-7 separate veins in the wire. Then the resistance will be less. At the expense of stretching the wire by the types of rubber, yes Popilin also here smoke in pampas.
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Impossible.....the litz wire must have a physical OD of at least 0,45 mm.
Otherwise you will not have a DCR equivalent to a 0,31 mm diameter normal magnet wire.
When calculating it is possible to have the 1784 primary turns with 0,45 mm diameter litz wire on your V51 core, together with the secondaries like you described.
Otherwise you will not have a DCR equivalent to a 0,31 mm diameter normal magnet wire.
When calculating it is possible to have the 1784 primary turns with 0,45 mm diameter litz wire on your V51 core, together with the secondaries like you described.
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to JMFahey
Dear Sir what you said is not acceptable for one simple reason:
If the answer was: I am not agree because etc, etc, etc, is acceptable because a discussion cas start to reach a final results, maybe.
But if the answer is : NOT! who sent this answer must be able to demonstrate why!!!!!
If you say NOT you must have the tools ( I suppose) to show the reason why you are right and me wrong!!!!!
not only formulas that is only a copy/and paste exercise!!!
In a scentific field if someone present a result of a study, some other (that consider that results bad ) have the time and the capability to explain why in the same way
( I don't know if the concept is clear)
This is a big difference; in this way the people that spent time and money to present tests and project are under the fire of some people that say NOT! without any practical aspect, only theory.
Please leave latin, it is for a more important things not peanuts as we are talking here!! 🙂
Walter
Dear Sir what you said is not acceptable for one simple reason:
If the answer was: I am not agree because etc, etc, etc, is acceptable because a discussion cas start to reach a final results, maybe.
But if the answer is : NOT! who sent this answer must be able to demonstrate why!!!!!
If you say NOT you must have the tools ( I suppose) to show the reason why you are right and me wrong!!!!!
not only formulas that is only a copy/and paste exercise!!!
In a scentific field if someone present a result of a study, some other (that consider that results bad ) have the time and the capability to explain why in the same way
( I don't know if the concept is clear)
This is a big difference; in this way the people that spent time and money to present tests and project are under the fire of some people that say NOT! without any practical aspect, only theory.
Please leave latin, it is for a more important things not peanuts as we are talking here!! 🙂
Walter
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1784 turns of 0.45mm overall wire + 0.05 insulation per layer is ok and still might have some 0.5 mm space left to reach half height! I don't know the gemoetry of the windings here but we check out easily.
I can put 118-119 turns of 0.45mm wire per layer. Let's be cautious and go for 118 turns. Using a scheme with 5 primaries and 4 secondaries where the primary is made of 2+4+4+4+2 =16 layers plus 0.05 nomex per layer I get:
16x118=1888 turns and a total primary height of 8 mm
Let's suppose I get another 8 mm for the seconday and 2.25 mm (9x0.25mm) for the insultation between the 8 primary-to-secondary interfaces + the outer layer using 0.25 mm Nomex.
The total height is 18.25 mm (max height is 19.7-19.8 mm average without getting out of the coil former). This means that the average turn lenght will be 23.7 cm.
Don't take it badly but I have only used that scheme for guitar amp OT's. Never got anything good for Hi-Fi. Too high leakage inductance for typical tube OT's. It might work for tiny transformers + low impedance but I haven't done all possible combinations....too many!!
I have no experience with flat wire and toroidals. Can only guess. Sorry.
I hate the idea of winding toroidals: I see it like a torture as I can get past 100 KHz even with the old good EI cores....
The point is not only in high frequency but also low. And also small losses on the resistances in the wires and losses of the magnetic circuit too. I'm designing a toroidal transformer on a nanocrystalline cores with an inductance of the primary winding of more than 500H. In toroids, a small parasitic capacitance is also important.
In a toroidal transformer, even simple partitioning for both a guitar amplifier with EI core will give a much better result, taking into account low losses.
The question was about the skin effect in a flat wire, even if it's an EI - cores.
In a toroidal transformer, even simple partitioning for both a guitar amplifier with EI core will give a much better result, taking into account low losses.
The question was about the skin effect in a flat wire, even if it's an EI - cores.
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By the way, this method of partitioning (½ primary winding - the entire secondary winding in one layer - ½ primary winding) is not only suitable for guitars if you wind the primary winding correctly and apply C-core.
Audio amplifier system
US 2924780 A
Priority Date
Jun 30, 1954
The inventors of the invention
Bereskin Alexander B
The original patent owner
Baldwin Piano Co
https://www.google.com/patents/US2924780
Audio amplifier system
US 2924780 A
Priority Date
Jun 30, 1954
The inventors of the invention
Bereskin Alexander B
The original patent owner
Baldwin Piano Co
https://www.google.com/patents/US2924780
Leakage inductance will be certainly less in toroidals respect to EI for the scheme. If you can get optimal primary-to-secondary coupling with minimal partitioning then you are fine. I cannot really answer this as I haven't done it.
I can get huge inductances with low leakege with EI and C-cores as well.
You need to talk to someone that works ith toroidals.
The skin effect in flat wire is a different beast because there will be two different processess occurring: lateral skin effect and depth of penetration. The lateral skin effect occurs first (i.e. much lower frequency). You can find artcles in net. How this compares to skin effect in round wire I haven't look at it in detail as I have never used flat wire.
Hehe...B. BERESKIN was the guy at Philips who first investigated the lateral skin effect.
That's quite old! So the question is: if it is so convenient why didn't become the standard in the golden age of tubes? The saga of class B amplifiers for Hi-Fi started with McIntosh and although it works fine there are BETTER ways to make amplifiers. The coupling coefficient in OT's is a big issue for this type of amplifiers. It is NOT for class A and AB amplifiers in most operation modes. At the end of the day you still need to light up heaters so the efficiency of valve amplifiers is still bad when compared to solid state class AB amps. 😉
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Thanks for the more detailed winding scheme 😉
However, as Walter already mentioned, with the number of primary turns there is not enough inductance for a good output transformer.
The subject of this thread is using litz wire; until now we have been busy to get the correct information from Walter wrt the primary litz wire, and with his "random" info it is not easy to proceed any discussion on the subject.
I guess that he has 0,45 mm OD litz wire equivalent to 0,31 normal magnet wire for the primary, but he does not take the effort to confirm or correct 😡😡😡
Probably this is the same Bereskin, since he offers such a clever bifilar winding in this patent.
A lot of good ideas and schemes did not become standards, because of poor marketing, although they were studio standards among professionals. See the paper clip. Neumann LV-60 power amp
Conversely, many bad or medium things have become icons because of aggressive marketing among the townsfolk, look at the marketers of Partridge and Peter Quortrup from AN.
Waltube, how do you form the Litz wire you use, do you twirl several strands into a single core cable prior to winding?
this is going to be too difficult to diy....so pictures of your work will help....
this is going to be too difficult to diy....so pictures of your work will help....
That I don't know as I haven't looked at it. It depends on the other things of course. Mine was just geometrical stuff....
or perhaps folks like then enough to buy them....after all marketing is real....
but interesting post you have, your mention of Bereskin rang beautiful bells in my head...
been looking at Bereskins' high power tube design using the 4-400 tubes...
i am wondering who else aside from him has done the traffo he mentioned in that article...?
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