Hmm...
Excuse me, but have you perhaps heard the saying?
"The plural of 'anecdote' is 'anecdotes', not 'data'."
To paraphrase:
"The plural of 'subjective' is not 'objective'."
Just because someone attends weekly Flat Earth Society meetings, and has never entertained a single soul of a different opinion, does not mean that they are, in any objective sense, or even a wider subjective sense, "right"...
Not to say you are a Flat Earther, but it sounds like you are well aware of some of the more, ahh, shall we say, "Curved Speaker Cone Society" types? 😀 Just because "they" say something, does not make it universally true.
You stated that amorphous and nanocrystalline do not make sense in (large signal) audio transformers.
In other words: EI (or maybe c-core, toroid) goss is good enough in your opinion.
That's your personal opinion as well, isn't it? Was is based on comparing core materials, or simply deduced from physical properties?
I respect your opinion which is not less subjective than mine.
Does it make sense to question subjective opinions?
Vitroperm is a nanocrystalline alloy, and for a cut core the Afe 300mm² would be rather small, and for a toroidal core you'd have one of the larger dimensions.
The preference for a toroidal core might be the better properties (cutting a nanocrystalline core partly damages some of the properties).
You mean 50/60Hz transformers?
What is suspect about these?
M6 goss is perfect for these, available in Ei, c-core and toroidal.
These core geometries have their pros and cons; nothing strange here.
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I'm try to understand what is the difference with core material on output transformer. Audio transformers are very different from distribution transformers One question is how to deal with this quick saturation of amorphous sheets. It may create some intermodulation distorsion mainly on loud bass in complex message?. That could explain the tone difference with GO steel sheet. Some people could enjoy this kind of distortion?
As long as the transformer is well designed, saturation is not an issue.
Differences in sound between the various core materials is caused by differences in properties of these materials, not in "overload behavior". The introduction of "slow" and "quick" saturation seems odd in this regard.
Please reread Cerrem's post #2.
Differences in sound between the various core materials is caused by differences in properties of these materials, not in "overload behavior". The introduction of "slow" and "quick" saturation seems odd in this regard.
Please reread Cerrem's post #2.
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Sorry for my english, I'm getting old.
What I'm try to say is: for a design at 20Hz, 1T you are more near 1.25T than 1.8T.
For distribution transformers (it's of course a different job) when Allied Signal launch the Metglass it was a totally different design. But of course if your transformers work and make good sound no problem.
Best regards
What I'm try to say is: for a design at 20Hz, 1T you are more near 1.25T than 1.8T.
For distribution transformers (it's of course a different job) when Allied Signal launch the Metglass it was a totally different design. But of course if your transformers work and make good sound no problem.
Best regards
Knowing the physical properties, and physics, yes. 🙂
My opinion isn't subjective, because unfeeling machines measure the same results. Or, if they measure different, that will be my opinion. My opinion really isn't a thing of substance. I don't imply subjective confidence in my factual statements; the data (when available) should speak for itself!
In ordinary conversation, this reads as a very weak opinion, and so I rarely have any power to convince people. That's fine; I'm a reasonable person, and reasonable people will listen carefully. Anyone who isn't convinced by facts, probably isn't a reasonable person, and doesn't interest me. For those who pay for my services, the quality of my work speaks for itself, as does its value!
Alas, here in the US we currently have the national battle of two persuasive speakers. Us reasonable people are saturated by inanity from all sides, while the masses cheer on unaware of their being manipulated... 🙄
OPTs have similar motivations, indeed worse as the lower frequency limit is a fraction that of mains. If you want full power at the lowest frequency, you need core, core and nothing but core!
High Bmax materials are preferred, but not if they increase cost unnecessarily (sure you can use 20% less, but if it costs 300% more..?!), and not if it means compromising mu_i.
You need some minimum mu_i, so as not to compromise small signal frequency response and introduce distortion (due to mu varying below saturation). Which will be the biggest impact on sound quality, and it is measurably and audibly worthwhile to do this!
Anything M6 or better is just fine.
Minimum permeability is something like 500 or 1000 for a practical transformer*. But if mu varies (say from 1000 to 3000 over the AC range), you'll get relatively strong effects, so if mu is low, a linear (slightly gapped, perhaps?) core is preferable. Otherwise, much higher mu (say 5000 or more) is better. The downside of the extended LF (small signal) range is a risk of motorboating.
*I forget what this number comes from, exactly. I never quite worked it out on paper. It depends on the resistivity of copper, core geometry, and other goofy parameters, so tends to be established empirically. Anyway, such a minimum exists, given a requirement that the small-signal (inductive) LF limit be equal or lower than the full-power (saturation) limit.
If you are okay with less power at low frequencies, but need the small signal bandwidth (flat to, say, 5 or 10Hz), then high mu is a bigger priority. Which should usually be served well enough by M6 or the like. Very high mu of permalloy or nanocrystalline (strip, not cut cores) will get you plenty of small-signal response, but won't get you any more power output capacity (because that's limited by Bmax).
Tim
What i read in news, china is moving to amorph tx AC. That should save lots of money on the losses. Even when tx are not cheap.
Sure it does looks nice, therefore people start asking, what amorph can do for audio.
Sure it does looks nice, therefore people start asking, what amorph can do for audio.
In Europe several firms made some prototypes in the 90 (Italia, France, UK etc). In USA some should be used in California?.
Of course on a grid the no-load losses and cable losses cost a lot of money. May be supra conductivity or private generator would be the future solution.
For output audio transformers, if some people find the sound better, why not, the question is open.
Of course on a grid the no-load losses and cable losses cost a lot of money. May be supra conductivity or private generator would be the future solution.
For output audio transformers, if some people find the sound better, why not, the question is open.
An amourphous core can handle about 60% less power, because also the stack factor is less.
The power output of your tubes is still the same so or you need a bigger core, or the maximum power at 20Hz goes up to 32Hz.
The benifits of amourphous alloys for power output transformers are not so big and i know a lot of guys who changes from metglas 2605 to HiB again, just for the better balance/ "tone color"/ better low end.
The power output of your tubes is still the same so or you need a bigger core, or the maximum power at 20Hz goes up to 32Hz.
The benifits of amourphous alloys for power output transformers are not so big and i know a lot of guys who changes from metglas 2605 to HiB again, just for the better balance/ "tone color"/ better low end.
60%?
Stacking factor of GOSS cores is between 0.9 and 1.
Stacking factor of amorphous cores is between 0.8 and 0.9 checking several sources, here one of them:
http://jeteas.scholarlinkresearch.com/articles/An Overview on Amorphous Core Transformers.pdf
I wrote the word also.....
1,8T vs 1,2T and the stack factor 98% vs 84% makes 60% differance in power capacity. But you probebly know that already.
1,8T vs 1,2T and the stack factor 98% vs 84% makes 60% differance in power capacity. But you probebly know that already.
Amorphous cores are some 20% less efficient in core excitation compared to GOSS (1.56T - 2T).
The lower stack factor of amorphous cores would give a total loss of efficiency of some 30 %, easily to be compensated by some higher core mass.
The lower stack factor of amorphous cores would give a total loss of efficiency of some 30 %, easily to be compensated by some higher core mass.
Well, we not want our cores in to saturation do we?
That's why i look at the BH-loop, not the saturation level, that makes no sense for a quality transformer. If you go to the Metglas site and look at the amcc serie you can easely calculate the stack factor. I made a small mistake, it's not 84% but 82% (amcc160)
The point was swopping cores...... So 60% less power for amorphous cores. Making the cores bigger as you say would be more costly and also some benifits of the amorphous would be less because coreloss is in kg, so more weight more loss. Btw in the example on the elector site your pse 300B transformer in HiB weights 9kg and your finemet weights less, 8Kg. Why is that?
That's why i look at the BH-loop, not the saturation level, that makes no sense for a quality transformer. If you go to the Metglas site and look at the amcc serie you can easely calculate the stack factor. I made a small mistake, it's not 84% but 82% (amcc160)
The point was swopping cores...... So 60% less power for amorphous cores. Making the cores bigger as you say would be more costly and also some benifits of the amorphous would be less because coreloss is in kg, so more weight more loss. Btw in the example on the elector site your pse 300B transformer in HiB weights 9kg and your finemet weights less, 8Kg. Why is that?
Thanks for your opinion, happy for you that you are satisfied.
I see manufactures as Tribute, Lundahl but also (not 100% sure but it looks like they do) Monolith Magnetics just swap cores. It's the easiest way but power loss is also present for about 60% as i stated in the previous post. Not all manufactures are honest about that fact.
I tryed amorphous and finemet c-cores too but i am not so sure about there quality. The high frequency and low frequancy repons is usually better for SiFe.
Nice to hear your response, fully agree.
You can clearly see the strap or metal band that keeps two "C" parts together. Unless x-former itself is heavily impregnated or varnished for different reasons you may disassemble it quite easily, introduce the gap you need and put it back in order. Coating makes such a process quite dubious. Due to fragility and extreme thinness of the tape the core is made of it can be easily damaged beyond reparation. Again it depends of type and amount of varnish used. Please bear in mind that most likely the core itself is impregnated using epoxy. Amorph has to have protective layer for a particular reason: it does rust.
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Transformer works just fine without the core, the latter merely keeps magnetizing current low enough.
There are hundreds if not thousands magnetic alloys out there. Old ones like Permalloy and such and "newer" ones like Metglass or Finemet. They could be quite expensive.
Impregnated types do have 5 to10 times worse specs in terms of hysteresis curve and subsequently losses in respect to the tape the core's made of. Metglass C-cores included.
Besides distribution such cores are used in common mode filtering, SMPS inductors and, most importantly in power meters' current transformers. The latter means really low magnetizing current and constant permeability or high linearity for that matter.
It's near impossible to gap unimpregnated core: see above. Please note that high flux density exists in a core only at low frequencies, so core related distortions do. At higher frequencies eddy current losses rule so it may have better high frequency response. However such cores have negligible losses up to few hundred kilocycles which, in turn, prevent passive dumping of the parasitic resonances in transformer itself.
There are rather "cheap" low alloying addition alloys with rather linear magnetization curve and saturation around 1.45 T. Are you ready for a thing that is not mass produced?
Cheers
There are hundreds if not thousands magnetic alloys out there. Old ones like Permalloy and such and "newer" ones like Metglass or Finemet. They could be quite expensive.
Impregnated types do have 5 to10 times worse specs in terms of hysteresis curve and subsequently losses in respect to the tape the core's made of. Metglass C-cores included.
Besides distribution such cores are used in common mode filtering, SMPS inductors and, most importantly in power meters' current transformers. The latter means really low magnetizing current and constant permeability or high linearity for that matter.
It's near impossible to gap unimpregnated core: see above. Please note that high flux density exists in a core only at low frequencies, so core related distortions do. At higher frequencies eddy current losses rule so it may have better high frequency response. However such cores have negligible losses up to few hundred kilocycles which, in turn, prevent passive dumping of the parasitic resonances in transformer itself.
There are rather "cheap" low alloying addition alloys with rather linear magnetization curve and saturation around 1.45 T. Are you ready for a thing that is not mass produced?
Cheers