Without wanting to hurt anyone`s sentiments...
Resulting in a jumble of magnetic fields, the transformer placement in question is indeed noticeably unfortunate. Preferably, the cores should be individually screened to reduce electromagnetic interference and noise.
Permeability is a measure of efficiency. In the light of audio signal distortion, the Q-factor carries opposite connotations. Permeability is inversely related to all parameters indicating low distortion, such as high values of magnetic flux density, magnetic susceptibility, retentivity, coercivity, reluctance, remanence.
The efficient toroid core exhibits poor paramagnetic ability, wide hysteresis loops and a predominantly capacitive rather than magnetic coupling between the primary and the secondary windings which means high distortion, poor frequency response and nasty transients.
Bandwidth drops rapidly with increasing load. Under practical loading conditions, even non-toroidal single-ended output transformers offer an insufficient signal bandwidth, in balanced-mode bandwidth shrinks further.
The production of core materials with desirable magnetic properties (consistent polarization, high magnetic flux density, low magnetic saturation, low diamagnetic dispersion) poses markedly raised manufacturing difficulty and cost.
Resulting in a jumble of magnetic fields, the transformer placement in question is indeed noticeably unfortunate. Preferably, the cores should be individually screened to reduce electromagnetic interference and noise.
Permeability is a measure of efficiency. In the light of audio signal distortion, the Q-factor carries opposite connotations. Permeability is inversely related to all parameters indicating low distortion, such as high values of magnetic flux density, magnetic susceptibility, retentivity, coercivity, reluctance, remanence.
The efficient toroid core exhibits poor paramagnetic ability, wide hysteresis loops and a predominantly capacitive rather than magnetic coupling between the primary and the secondary windings which means high distortion, poor frequency response and nasty transients.
Bandwidth drops rapidly with increasing load. Under practical loading conditions, even non-toroidal single-ended output transformers offer an insufficient signal bandwidth, in balanced-mode bandwidth shrinks further.
The production of core materials with desirable magnetic properties (consistent polarization, high magnetic flux density, low magnetic saturation, low diamagnetic dispersion) poses markedly raised manufacturing difficulty and cost.
Your first point - both cores are carrying virtually the same signal and will generate similar magnetic fields. Toroids have much less magnetic leakage then normal transformers. I cannot see having them near each other having any effect at all.
Your second point - not sure what you are saying.
I've seen on evidence that the bandwidth is much of an issue. It maybe a power transformer will not be very good at 20KHz, but I seen responses which are usable up to 50KHz.
They do tend to have much bigger primary inductance, but saturate more ea sally you do need to care of DC balance. They can pass 50Hz at full current and don't saturate (or they would get very hot).
In terms of construction I think they use the same steel plates as do conventional transformers overlapping and bent into a circle.
You get much better coupling factors without having to use interleaved windings.
I wrote it before that it's bad habit to stack toroids but as the bearer of the bad massage I got punished by forum members. Only positive feedback is allowed here. Its the same like Facebook and all other social media. The builder wants positive feedback for pushing his ego. If you critizice something, you will be punished by other members.
Might you please elaborate on this? How could some considerable amount of electrical energy in the 50/60 Hz range be transferred simply by a capacitor of, say, in the nF (10-9F) range?
Best regards!
Actually I think the builder just wanted some advise on what to build. I am just interested in the science. I guess N101N meant at high frequencies. I agree at high frequencies the core does not do much for you but the coupling is still mainly inductive not capacitive.
Last edited:
Surprisingly, this isn't the case with the big transformers because so many cheap SMPS mean DC bias on the AC outlet is a normal thing. I have actually used the PP interleaved setup with only one tube (a 120mA DC bias on the coil) and it still worked up to the SE power that the one tube could make without noticeable core saturation.
There is a difference between constructive critique and insulting comments. "The Builder" (me - I have a name) isn't looking for positive feedback, but I'm not looking for ignorant insulting comments, either. Even the fact you refer to me as "the builder" instead of by my name speaks volumes about the quality of your character. If you were referring to some other builder it wasn't clear.
First of all I think it is a fantastic idea. I will add to my list of things to build. (someday)
However.
Consider .jpg
Inviting discussion.
Off to work now.
Later
However.
Consider .jpg
Inviting discussion.
Off to work now.
Later
Attachments
Last edited:
There appears to be ultimately, ZERO EM fields existing either external or internal to the structure of a toroid..."Youtube: Magnetic Field Outside a Toroid"
There is a bit of math to do in this video, plug-in the numbers in the formulas & see what you get...So we can all stack our toroids just fine...your welcome.
-------------------------------------------------------Rick..............
There is a bit of math to do in this video, plug-in the numbers in the formulas & see what you get...So we can all stack our toroids just fine...your welcome.
-------------------------------------------------------Rick..............
Not every YOU-TUBE video tells the truth.
Better to read from literature that is worth reading it and don't waste your time with videos.
>Stacking cores will increase the cross section (Ae) by the multiple of the number of cores in the stack.
The magnetic path length (le) will remain constant. The AL can be estimated by the same method as
for single sets, where a leakage adjustment is estimated based on the ratio of window area (WA) to
core area (Ae). Because that ratio decreases as cores are stacked, the AL of n stacked sets are
slightly less than n times the AL of a single set.<
https://elnamagnetics.com/wp-conten...tics-Documents/Frequently_Asked_Questions.pdf
The stacking of toroids changes its determined magnetic properties.
Last edited:
Less Magnetic Field Noise
Do you know Schmitz, I also use this way to place Toroids in my AMPs.
And do you know, the Magnetic Distortion to other Components is much less than side by side.
This alone makes it worth to do it..
And that you never have seen this, doesn't mean that this is wrong.
Do you know Schmitz, I also use this way to place Toroids in my AMPs.
And do you know, the Magnetic Distortion to other Components is much less than side by side.
This alone makes it worth to do it..
And that you never have seen this, doesn't mean that this is wrong.
Last edited:
Good Critics are always welcome, everywhere, also here
It's the way the critics are written... the sound makes the music.. if you understand what I mean.. Honestly I think quite frankly that here on this Forums the Members are fair to each other.
Schönen Abend noch..
Gruss aus der Schweiz
Chris
It's the way the critics are written... the sound makes the music.. if you understand what I mean.. Honestly I think quite frankly that here on this Forums the Members are fair to each other.
Schönen Abend noch..
Gruss aus der Schweiz
Chris
>Stacking cores will increase the cross section (Ae) by the multiple of the number of cores in the stack.
That is correct if the winding goes through both cores but not if each toroid has a separate winding. The magnetic field circulates around the toroid not through the centre - so they don't couple much when placed on top of each other.
That is correct if the winding goes through both cores but not if each toroid has a separate winding. The magnetic field circulates around the toroid not through the centre - so they don't couple much when placed on top of each other.
Last edited:
What you or any other DIY do for creating a private tube amp is absolutely irrelevant. That doesn't set the standard in electrotechnical engineering. It just shows a lack of knowledge how to build amps in the way it should be done.
I would have never done this because I'm not a foreigner in this engineering field.
But most DIY'er are. They do things and build amps the way no engineer ever would. If NASA would have done so, they would have never successfull manage to fly to the moon. If you do your projects without the knowledge and a good practise, at least you shouldn't advise others to do so.
But for you, only the ego counts. Regardless whether its no good engineering practise or not. The most important is, you can do it. And I'm not against this, because I've never must hear or visit your tube amp creations. So its meaningless for me at last. You are free to do whatever you want in electronics.
Ah, now I know why I didn't manage to get earlier to the moon than the NASA in 1969 when I was a 10 year old boy. Thanks for the insight 😀!
Best regards!
Best regards!
One thing I learned in my engineering career is that you will have nearly as many different and often conflicting OPINIONS on a subject as there are engineers associated with it. This is from an engineering facility where over 1000 engineers of various disciplines worked. Many of these can back up their opinions with logical and justifiable solid engineering.
Putting 65 engineers in a large conference room and trying to design a cell phone by committee leads only to CHAOS! If a design were to emerge from that room, it would be a bland "least common denominator" piece of junk. I avoided all such scenarios whenever possible.
This situation is also very much in play in the audio world too.
The OP stated that he wanted a "bedroom power" level amp, and that he preferred PTP construction. The discussion of PC boards in not needed.
These are his only choices so far. We can't even make tube choice recommendations at this point since we don't know where in the world he resides. What's common in Europe is not always common here, and vice versa. The power output levels for "bedroom" SPL can range over 20 dB or more depending on the choice of music, and speaker sensitivity.
I have stacked toroids in some of my amps and would do it again. Ugly, yes. Bad engineering? Not in my opinion. I wouldn't stack an OPT on a power supply toroid, but power on power, or OPT on OPT is OK provided there is sufficient insulation for the voltage levels involved and sufficient mounting stability.
Again, this does not matter yet.....the OP may prefer conventional EI transformers. Until we know this, the stacking toroids debate is pointless.
Putting 65 engineers in a large conference room and trying to design a cell phone by committee leads only to CHAOS! If a design were to emerge from that room, it would be a bland "least common denominator" piece of junk. I avoided all such scenarios whenever possible.
This situation is also very much in play in the audio world too.
The OP stated that he wanted a "bedroom power" level amp, and that he preferred PTP construction. The discussion of PC boards in not needed.
These are his only choices so far. We can't even make tube choice recommendations at this point since we don't know where in the world he resides. What's common in Europe is not always common here, and vice versa. The power output levels for "bedroom" SPL can range over 20 dB or more depending on the choice of music, and speaker sensitivity.
I have stacked toroids in some of my amps and would do it again. Ugly, yes. Bad engineering? Not in my opinion. I wouldn't stack an OPT on a power supply toroid, but power on power, or OPT on OPT is OK provided there is sufficient insulation for the voltage levels involved and sufficient mounting stability.
Again, this does not matter yet.....the OP may prefer conventional EI transformers. Until we know this, the stacking toroids debate is pointless.