I suggest you accept any help from BudP that you can get.
In a Philips Tech Library book by E.Rodenhuis "HiFi Amplifier Circuits", a detailed instruction for winding a PP UL transformer for a 20w EL84 amp is given To get very good performance it has 10 primary and 8 secondary coils to provide matching to 8 and 16 ohms. Central core is 50mm x 25mm.
In a Philips Tech Library book by E.Rodenhuis "HiFi Amplifier Circuits", a detailed instruction for winding a PP UL transformer for a 20w EL84 amp is given To get very good performance it has 10 primary and 8 secondary coils to provide matching to 8 and 16 ohms. Central core is 50mm x 25mm.
Hi rjb,
I hope that "those that know" are watching and will point us in the correct direction should we stray! I know this is a big learning curve and is not meant to be a closed discussion. Hopefully we will get to a point where we have a small pp trasformer as a first attempt with good performance. If this works then we can try and get more advanced.
Just a thought "an engineer can build an engine with a drawing not having to do the design if the parts are available". For valve lovers this would also be true with a drawing an some engineering knowledge.
I was hoping BudP would comment!
Regards
M. Gregg
I hope that "those that know" are watching and will point us in the correct direction should we stray! I know this is a big learning curve and is not meant to be a closed discussion. Hopefully we will get to a point where we have a small pp trasformer as a first attempt with good performance. If this works then we can try and get more advanced.
Just a thought "an engineer can build an engine with a drawing not having to do the design if the parts are available". For valve lovers this would also be true with a drawing an some engineering knowledge.
I was hoping BudP would comment!
Regards
M. Gregg
No, this design can't be converted in an UL one simply by adding taps.
You must use completley different winding organisation to maintain symmetric coupling between anodes, screens and LSP windings.
Core size and type is indicated at the bottom : 22mm by 34mm thongue, M6X laminations.
Yves.
Yes, it's still my dayly amp !
See the original schemo here:
Push Pull ECL86/6GW8
Local feed back around the output stage was used to reach the lo Rp of triodes while keeping the efficiency of pentodes.
You will see that the OPT design was slightly modified (use of Mylar Celite instead of Teflon that not proved to be superior but more difficult to get)
A friend of mine also draw a PCB for "lazy" builders . . .
Audiyofan.org • Afficher le sujet - Commande groupée PCB pour Push-Pull ECL86 Dissident Audio
Sorry, loooong french speaking thread but pictures say almost all
As far as I know, about a dozen was built successfully.
Yves.
See the original schemo here:
Push Pull ECL86/6GW8
Local feed back around the output stage was used to reach the lo Rp of triodes while keeping the efficiency of pentodes.
You will see that the OPT design was slightly modified (use of Mylar Celite instead of Teflon that not proved to be superior but more difficult to get)
A friend of mine also draw a PCB for "lazy" builders . . .
Audiyofan.org • Afficher le sujet - Commande groupée PCB pour Push-Pull ECL86 Dissident Audio
Sorry, loooong french speaking thread but pictures say almost all
As far as I know, about a dozen was built successfully.
Yves.
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BA-TrafoWiz
I can calc windings for push-pull (not SE, sorry), EI & Double C Core, M3/M4/M6 CRGO silicon steel (I may add Hi-B and permalloy later, but right now I have no enough data to do so).
Software is based on methodology known as "method of equivalent generators" which I took from the number of academic-level Russian books published in 50th and 60th. I verified data generated by software from book's samples, and it was correct.
Apart from number of turns, my software BA-TrafoWiz provides approximate values for leakage inductance, low-frequency roll-off (at max/low power) caused by idle current imbalance, parameters of final coil/windings dimensions (incl. R(dc) of both), and simulation of winding process which allow to check how windings fit coil/bobbin much more precisely then generic formulas. So far I programmed 4x4 layout only.
Also, it estimates worst-case scenario analysis of THD/IM, but it seems to be based on very old data and low-quality iron, so results are overestimated at 10x degree I believe.
I ordered 2 sample transformers which I designed with this software, they stand on my table, but I had no time to finish tests amp unit yet (as the Russian joke goes "shoemaker left without boots").
There is a plenty of controversy in various areas of audio transformer design (e.g. A/AB class primary# of turns, including or excluding approx efficiency in secondary winding calculation, etc.). Each author/engineer insists on its own version of truth, so its up to you to accept or decline all that stuff.
I can start new thread for core submission, and upon having free time will post calculations.
Offer is free as freedom of speech
I can calc windings for push-pull (not SE, sorry), EI & Double C Core, M3/M4/M6 CRGO silicon steel (I may add Hi-B and permalloy later, but right now I have no enough data to do so).
Software is based on methodology known as "method of equivalent generators" which I took from the number of academic-level Russian books published in 50th and 60th. I verified data generated by software from book's samples, and it was correct.
Apart from number of turns, my software BA-TrafoWiz provides approximate values for leakage inductance, low-frequency roll-off (at max/low power) caused by idle current imbalance, parameters of final coil/windings dimensions (incl. R(dc) of both), and simulation of winding process which allow to check how windings fit coil/bobbin much more precisely then generic formulas. So far I programmed 4x4 layout only.
Also, it estimates worst-case scenario analysis of THD/IM, but it seems to be based on very old data and low-quality iron, so results are overestimated at 10x degree I believe.
I ordered 2 sample transformers which I designed with this software, they stand on my table, but I had no time to finish tests amp unit yet (as the Russian joke goes "shoemaker left without boots
").There is a plenty of controversy in various areas of audio transformer design (e.g. A/AB class primary# of turns, including or excluding approx efficiency in secondary winding calculation, etc.). Each author/engineer insists on its own version of truth, so its up to you to accept or decline all that stuff.
I can start new thread for core submission, and upon having free time will post calculations.
Offer is free as freedom of speech
I've got some EI 112, 0.014"(or .356mm) from here:
PRODUCTS
I also have some bobbins for a square stack (which you can split if you need a bigger stack).
You can have for shipping (and maybe a small contribution to DIY, if you are feeling generous).
Enough for a few parties to make a pair of small PP transformers (SE too, if you only need a couple of watts).
Sheldon
PRODUCTS
I also have some bobbins for a square stack (which you can split if you need a bigger stack).
You can have for shipping (and maybe a small contribution to DIY, if you are feeling generous).
Enough for a few parties to make a pair of small PP transformers (SE too, if you only need a couple of watts).
Sheldon
For exemple if you decide to wind with more than "one wire at hand" that is "bifilar", "trifilar", and so on . . .
This may helps in optimizing the filling of the bobbin.
Yes, but i'm so lazy and writing an "user manual" is a difficult (and bothering) job.
It happens someone else started to do so, look at
DIY Simple Output Transformer
I'm looking above its shoulder . . .
You probably don't need to double the core size, but if you play with OPT-da, it will tell you
But, please remember it's only a tool, a stupid tool wich will give stupid results if feed with -ahem- stupid requierements . . .
Oh, which version have you downloaded ?
Yves.
The next problem is a counter:
From hack a day I tried wiring a calculator so the = button connected to a reed Sw and entered 1+1 operated the switch with a magnet and we get 2,3,4,5,6,7..LOL
And if we enter 192 T and -1 we get 191, 190, 189.
I do not know what speed it will count at, only testing at the moment.
I would only want to go quite slowly to get the windings in place.
Just thought it may help someone.
Regards
M. Gregg
From hack a day I tried wiring a calculator so the = button connected to a reed Sw and entered 1+1 operated the switch with a magnet and we get 2,3,4,5,6,7..LOL
And if we enter 192 T and -1 we get 191, 190, 189.
I do not know what speed it will count at, only testing at the moment.
I would only want to go quite slowly to get the windings in place.
Just thought it may help someone.
Regards
M. Gregg
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Err, You dont....
This is a function of the voltage swing and the required power output.
The volts per turn and the number of turns per coil....
More turns less volts per turn...
Ive used this program a few years ago to make a SE Tx for a 6C33C, Worked pretty well!
It takes a bit of getting used to--at least for my feeble brain, but all I can advise is just play around with the variables, but note the winding height, the insulation thickness availability and the available bobbin height...
Personally, I think that this program from Yvesm is perhaps the best I have seen, It gives a great starting point and a huge learning curve while designing a very real and working transformer at the end...
Top marks for Yves!
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