I will never have 4 ohm speakers
I will think parrallel with you
If I design for something like 6,5 ohm it could be useful for both but 8 it will be
Hi
50AE
I'd like to know how you find the capacitance factor for de first 1/2 primary : 0,293
I dont know the rule how give result
Many thanks
Yan24
50AE
I'd like to know how you find the capacitance factor for de first 1/2 primary : 0,293
I dont know the rule how give result
Many thanks
Yan24
Thanks
I had read that paragraph, without taking it into account.
AMHA, i think P Turner simplified the calculation by taking the average area for each interface.
It is more accurate to take the real surface of each.
If you're speaking about Mean Turn Length, then yes, especially for fatter coils with higher turn length variation. I usually don't bother with coil heights bellow 13mm. The capacitance multiplier, dielectric thickness and constant contribute for the most of the P/S capacitance.
The primary to primary capacitance for most cases is negligible, although in some cases it can be deliberately increased. It is reduced by the smooth gradual voltage gradient due a typical high amount of primary layers in an OPT, and the series connection of the layers. It can go as low as 50pF with core to primary included.
The primary to primary capacitance for most cases is negligible, although in some cases it can be deliberately increased. It is reduced by the smooth gradual voltage gradient due a typical high amount of primary layers in an OPT, and the series connection of the layers. It can go as low as 50pF with core to primary included.
✅Yes, it's spread across the internet. But how can a beginner judge what is right and what is not?
I am designing a spool with 12 sections to wind them at 90° from the iron (Pi windings), I wasted nights reading many articles.
Today an Eng. who works in the production of amplifiers in a small-scale production advised me to abandon this fanciful idea.
I would need to live 800 years and have a lot of money to turn my life into one big laboratory of frustrated attempts.
It's rare to find people willing to help, that should be the true meaning of the existence of a forum.
I challenge anyone to find a practical teaching to build an audio transformer in a forum, anywhere, in Japan or Mongolia.
Many people resort to DIY like me because they are poor and haven't had the opportunity to study. An Eng. graduated here in Brazil, what will you learn in this area? We don't have technology, we don't have a heated technology industry like Europe and the USA or part of Asia.
What's left for me? "begging for help here and there...
I thought about buying this one and installing a wire tensioner.
https://pt.aliexpress.com/item/1005...37460.0.0.37da2e0esQfjAa&gatewayAdapt=glo2bra
Well the information that is spread across the internet usually assumes that you know the basics. If you knew the core fundamentals, then reading all that info would make a lot more sense.
In my own words, all you are doing when you design a transformer is to get the most amount of inductance, the least amount of capacitance, with the least amount of wire and the smallest core you can get away with. All while maintaining your winding ratio, managing heat, and making sure your core is no where near saturation.
You are ultimately building an electromagnet that is inducing a current on the output wire. Like with any electromagnet, there are losses. There is core loss, copper loss, flux leakage and a few others. As a result, a transformer is not 100% efficient. That being said, the closer you get to 100% efficiency, the better the transformer will sound.
All the tricks you read about online are nothing more than someone else's attempt to get close to a perfectly efficient transformer. However, a majority of them come at a cost. Pi windings are great for reducing capacitance and having really nice top end clarity. However, you generally have to use a special bobbin or a pretty nice machine to wind those correctly. Chances are you won't fill your winding window as efficiently and you won't have as much inductance. As a result, you lose a little bit of bass.
It's all a balancing act.
It becomes almost impossible to overcome these obstacles.
That name just takes me here: https://www.google.com/search?q=Pat...FDuIQ_AUoAXoECAIQAw&biw=1523&bih=736&dpr=1.25
Try this. His main site is down because he passed away last year. Here is a mirror site.
https://atrad-audio.co.nz/turneraudio/www.turneraudio.com.au/index.html
When you talk about a smaller amount of wire and smaller core, are you thinking about savings or does this action of reducing the wire bring improvements to the sound?
What would "correctly" mean? if you would tell me how to curl the coils correctly, i am sure i will curl the coils correctly with my chinese curler. I just need to understand how this should be done. I'm a driver and I know how to drive, but sometimes I need to ask someone the way, if they show me the way, I'll definitely go there.
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Using less wire will reduce resistance(pro), capacitance (pro), inductance(con) and heat(pro), using smaller cores will reduce core loss. Or you could use square profile wire to get the same number of turns but with a smaller gauge wire.
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Trying to wind pi windings by hand without a bobbin is hard to do because each coil has no lateral support. So your wire layers have to be under pretty high tension and wound verrrrrrrryyyyyy neatly. Otherwise your winding will collapse out the side and you will have to start all over again.
Neither did I find too much knowledge. Books are not enough, you need to build a bunch transformers and study them to find out what's really going on. It takes a lot of notes, analyzis and sleepless nights. I designed over 200 audio transformer prototypes and everyone of them was sitting on the bench, carefully measured for every HF behaviour possible. 7 years from where I started, I am now able to predict just by looking at the interleaving and capacitance distribution how the transformer will behave. I'm also working on SPICE simulating different transformer models.
Information on the internet can be a double-edged sword. You'll find out eventually here is a lot of MISinformation as well. Patrick Turner's website is however a very safe start, I can guarantee on that.
Pi windings are not something special, neither are they a free lunch. First, you inverse the leakage inductance geometry. In practice Pi wound transformers are aimed for leakage inductance dominance in mind. To achieve low Ls with a Pi geometry, you need the other way - taller windings, taller bobbin.
Second, it is not low capacitance proof if you don't know what you're doing.
Interleaving is not best or ultimate, it is designed optimally for your current goal and available materials.
IMHO, the best application for Pi winding is input transformers.
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Funny to come across this thread during a Google search, I started down this rabbit hole around two weeks ago.
I've read RDH4 Chapter 5 a few times, read through Igor Popovich's book as well and started creating an Excel spread sheet for single-ended OPT calculations. I will start reading into Patrick Turner's site this evening.
Sourcing small quantities of materials is an issue I've found. For those in the USA, Edcor currently is not selling EI M6 laminations. Also, don't bother reaching out to Tempel, they have a MOQ of 2K pieces. I am waiting to hear back from Thomas & Skinner, recommended to me by Tempel. Sounds like others have had success there.
Here is another document beginner's might find useful: http://www.tubetvr.com/transformers.pdf
I've read RDH4 Chapter 5 a few times, read through Igor Popovich's book as well and started creating an Excel spread sheet for single-ended OPT calculations. I will start reading into Patrick Turner's site this evening.
Sourcing small quantities of materials is an issue I've found. For those in the USA, Edcor currently is not selling EI M6 laminations. Also, don't bother reaching out to Tempel, they have a MOQ of 2K pieces. I am waiting to hear back from Thomas & Skinner, recommended to me by Tempel. Sounds like others have had success there.
Here is another document beginner's might find useful: http://www.tubetvr.com/transformers.pdf
I also learned (a little part of) the secrets of output transformers from my faults. I used a salvaged output transformer with EI130 0.35 mm laminations, and a dual chamber bobbin. The planned transformer has a turns ratio 20:1 for 8 ohms secondary, for push-pull UL output. So the primary and the secondary is center tapped. The initial results were disappointing, HF oscillation, peaks and dips in the audio band, etc.
At the end I found that sectioning and how to connect each section is the trick. Described here:
https://www.diyaudio.com/community/...without-global-nfb.384100/page-4#post-6987619
and here:
https://www.diyaudio.com/community/...without-global-nfb.384100/page-5#post-6991884
At the end I found that sectioning and how to connect each section is the trick. Described here:
https://www.diyaudio.com/community/...without-global-nfb.384100/page-4#post-6987619
and here:
https://www.diyaudio.com/community/...without-global-nfb.384100/page-5#post-6991884
The thinness of the laminations has the benefit of maintaining the effective permeability of the core (and hence primary inductance) to as high a 'low frequency' as practical, with the aim of suppressing low frequency phase shift and roll-off gain in the region where it can complicate GNF stability. This topic come up recently in https://www.diyaudio.com/community/...ncy-dependent-inductance.389901/#post-7118671 . The last reference in that discussion is available via https://ur.booksc.eu/book/39310494/1a2ebb .
those looking to wind their own traffos are in a better position to day than when this site opened...
lots of good stuff, beginning with teh RDH 3 and 4 free to download...
also many fine examples from Yves Monmagnon of dissidentaudio...
Patrick Turner website, go print your self a pdf copy of his pages so you can read over and over again..
then there is Bud Purvine who gave me lots of tips and useful data too...
lots of good stuff, beginning with teh RDH 3 and 4 free to download...
also many fine examples from Yves Monmagnon of dissidentaudio...
Patrick Turner website, go print your self a pdf copy of his pages so you can read over and over again..
then there is Bud Purvine who gave me lots of tips and useful data too...
Congratulations! You've learned about the importance of capacitance distribution the hard way. I did it the hard way too. When you start winding transformers, you always get some failed or not "so perfect" projects you start analyzing on the bench. For more details, I'm preparing a lecture on capaciance and leakage inductance distribution for the future.
All your results from post #72 make sense to me. What you did do with the secondaries, you cross coupled the sections from one to another you used their mid-center as ground. That way you achieved the following:
-Rdc equalization of the secondary packages
-More equal capacitance distribution (potentially killing that HF resonance)
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Dear Sir
I have no any further more info about this book. And it's difficult to buy one. Can you give me more detail about the book?
Thank you!
Andy
Random reading articles is not enough, watching YT videos even worse.
Best is to study it properly, as in
* Physics at a High School
followed by
* Engineering at an University
followed by
* practical experience designing, building and measuring.
If not the full path, get as close as possible, but minimally you will need to know the Physical basics (otherwise knowledge becomes a motley collection of blanket statements and half-truths)
Maybe he was talking about the "instant knowledge" path?
Of course he followed the 3 step path I suggest above.
Your Engineer friend is not 845 years old, is he? 😉
Think 5 years High School, 5-6 years Engineering plus, say, 3-4 years expeince and you´ll have solid knowledge behind your back 🙂
Working at least 2 years in an already established Factory won´t hurt at all.
Forums are excellent as an exchange-of-ideas place, asking help on certain definite points, etc. ; not the means , capabilities or focus enough to substitute proper full studies, of course.
WHAT are you talking about?
Brazil is fully comparable to the highest level Transformer Industry in the World, go figure.
Both domestic designers-builders and branches of International ones, specially because of HEAVY Customs Industry protection, high Tariff barriers, etc.
IF you want to sell in the HUGE and profitable Brazilian market, you have to set your factory there, period.
(Hint: I had to do that myself: get radication, RNE ID card, etc.)
Or become partners with a local important Factory.
Even mighty JBL had to buy shares and associate with Selenium to achieve that.
The BIG advantage being that products are made inside Brazil, while lots US ones are actually made in China and other Asian Countries.
Or at least in Canada or Mexico.
Here´s but one example, US Toroids Factory had to set up a branch inside Brazil, and manufacture locally.
To original high US standards, of course:
http://www.toroid.com.br/novo/wp-content/uploads/2018/04/Transf-audio-valvulados.pdf
My good friend Pedrone in Sao Paulo makes these mighty KT88 powered monoblocks, using those high quality (Brazilian made) transformers, go figure:
Start by reading books as suggested above, and have a High School level Physics book handy to dispel basic doubts.
There even is a huge section called "Electricity and Magnetism" go figure.
Such as:
https://www.google.com/search?q=ele...HRG9AJ8Q_AUoAXoECAEQAw&biw=1024&bih=514&dpr=1
In fact, I suggest you read it first.
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