Hi Looneytunes,
Thanks for the contribution. Already said in different ways: There is no such thing as a (conductive) material's "sensitivity" to flux change in a transformer. Simply put, as with any source of electricity, the basic (ideal) equivalent circuit is a constant voltage source in series with a resistance. The output will depend on the value of the load connected to this. If that load resistance is high enough, you could even wind your transformer with resistance wire. The sensitivity of a winding to low level signals is entirely a function of the core's reaction to whatever energy the primary is "trying" to induce in it (coupling efficiency disregarded for the moment). It unfortunately needs a minimum amount of energy for the core to "start". Fortunately modern steels are quite good at this, not to go into greater detail.
Sorry for Electra-Print - no go. As my respected Scottish friend said (also quoted elsewhere on this forum): "Ya should na listen to all the old wives' tales ya hear."
Regards
Thanks for the contribution. Already said in different ways: There is no such thing as a (conductive) material's "sensitivity" to flux change in a transformer. Simply put, as with any source of electricity, the basic (ideal) equivalent circuit is a constant voltage source in series with a resistance. The output will depend on the value of the load connected to this. If that load resistance is high enough, you could even wind your transformer with resistance wire. The sensitivity of a winding to low level signals is entirely a function of the core's reaction to whatever energy the primary is "trying" to induce in it (coupling efficiency disregarded for the moment). It unfortunately needs a minimum amount of energy for the core to "start". Fortunately modern steels are quite good at this, not to go into greater detail.
Sorry for Electra-Print - no go. As my respected Scottish friend said (also quoted elsewhere on this forum): "Ya should na listen to all the old wives' tales ya hear."
Regards
dissing silver
Since some are dissing companies that market silver in their output transformers, why not diss Audio Note? Their most expensive transformers (and there are quite a few models) have silver, some in the secondary only, even more expensive ones with silver in both primary and secondary. Is Audio Note guilty of selling snake oil?
" the harder the sell the more desperate the company
I lose respect for companies who talk without backup and avoid them like the plague "
Does this include avoiding Audio Note since they market silver too?
Since some are dissing companies that market silver in their output transformers, why not diss Audio Note? Their most expensive transformers (and there are quite a few models) have silver, some in the secondary only, even more expensive ones with silver in both primary and secondary. Is Audio Note guilty of selling snake oil?
" the harder the sell the more desperate the company
I lose respect for companies who talk without backup and avoid them like the plague "
Does this include avoiding Audio Note since they market silver too?
Jamesdb,
I accept that your remarks were not aimed at me in particular.
But the valid point here, at least in my opinion, is that whenever something is sold as being "better" and that cannot be backed up by science or is even contrary to science, such a company (or person) is in fact misleading the man-in-the-street. It is natural to expect that folks who produce something know what they are doing, and as such their views carry weight.
You will know that this is not an uncommon occurrence, and sometimes such absolute drivel are dished up, that one cannot be blamed for becoming sceptical. In this respect the use of silver wire is by far not a serious objection, but as far as I know it is more expensive than copper, so one would simply like to know why. I have yet to see a valid answer. I myself would not "dis" a whole company for one doubtful practice, but my question stands - whatever the reputation of the company or person.
Scientists do not know everything, but we know certain things - and science is blind to reputation.
I accept that your remarks were not aimed at me in particular.
But the valid point here, at least in my opinion, is that whenever something is sold as being "better" and that cannot be backed up by science or is even contrary to science, such a company (or person) is in fact misleading the man-in-the-street. It is natural to expect that folks who produce something know what they are doing, and as such their views carry weight.
You will know that this is not an uncommon occurrence, and sometimes such absolute drivel are dished up, that one cannot be blamed for becoming sceptical. In this respect the use of silver wire is by far not a serious objection, but as far as I know it is more expensive than copper, so one would simply like to know why. I have yet to see a valid answer. I myself would not "dis" a whole company for one doubtful practice, but my question stands - whatever the reputation of the company or person.
Scientists do not know everything, but we know certain things - and science is blind to reputation.
science or belief
I don't know about transformer science. I know that succes counts in science. Top rank OPT's designed by Menno van der Veen are solded bij Amplimo and Plitron. Some models are offered with silver windings. Without doubt they sound better than the copper ones who are already very good. That is a fact. If some scientist cannot explain this that does not change anything about this fact.
I don't know about transformer science. I know that succes counts in science. Top rank OPT's designed by Menno van der Veen are solded bij Amplimo and Plitron. Some models are offered with silver windings. Without doubt they sound better than the copper ones who are already very good. That is a fact. If some scientist cannot explain this that does not change anything about this fact.
Jaap,
Your stance cannot be criticised - if that is your experience, I will respect it. But to me it was always reasonable to ask why. I presume there must have been some argument behind this by the designer; it is a little uncommon to accept that transformers were wound in different ways and with different materials, and that what was adopted in the end was done so purely by chance, as it were, on the strength only that it sounded better to some people. Transformer science is a little more exact than that, I can assure you! (We are talking about basics here, not some cutting-edge technology.)
But we are going off-track, started by my question in my post #34, and my apologies to Tmblack for this. Until some later time then, I will have to accept that silver wire has some magical advantage over copper, not yet discovered by science even in this enlightened day of rocket science.
Regards
Your stance cannot be criticised - if that is your experience, I will respect it. But to me it was always reasonable to ask why. I presume there must have been some argument behind this by the designer; it is a little uncommon to accept that transformers were wound in different ways and with different materials, and that what was adopted in the end was done so purely by chance, as it were, on the strength only that it sounded better to some people. Transformer science is a little more exact than that, I can assure you! (We are talking about basics here, not some cutting-edge technology.)
But we are going off-track, started by my question in my post #34, and my apologies to Tmblack for this. Until some later time then, I will have to accept that silver wire has some magical advantage over copper, not yet discovered by science even in this enlightened day of rocket science.
Regards
If to use more expensive silver wire it is logical to use as well better iron and winding methods, right? I suppose that real Masters do that.
But if somebody wants to make better transformer using cheap iron and bulk winding no silver or platinum helps.
The same like potted cheap power transformer instead of output transformer does not give a sound even if the pot is polished and shiny.
But if somebody wants to make better transformer using cheap iron and bulk winding no silver or platinum helps.
The same like potted cheap power transformer instead of output transformer does not give a sound even if the pot is polished and shiny.
Johan Potgieter said:
Why is it hard to accept? It makes perfect sense to me; a manufacturer offers the customer whatever they want most.
Let's consider the completely different example of automobiles. Suspension geometry is straight forward enough. Given all of the forces and loads involved it's easy enough to figure out what the patch of tire that is contact with the road will do relative to the rest of the car. Yet, if drivers report that one suspension results in better handling than another, why would car builders ignore it just because they don't understand *why* it handles better?
It is entirely natural for them to want to understand why, but not understanding does not negate the opinions of the drivers. Obviously, they build what their customers want to buy. And it should be no surprise of they hide their lack of understanding behind a sales pitch. But there is no shame there; apparently nobody understands, so they are not alone.
-- Dave
Hi Dave,
We are going quite off-topic and I can feel a moderator fingering a yellow card somewhere, but I hope a last commentary on this subject can slip in.
I think we are on slightly different tracks, even though toward the same goal. Your example is taken, but a manufacturer will not (I hope!) design "what the customer wants" if it violates principles to the extent that the customer is mislead in the broadest sense of the term (dangerous practice, unnecessary high cost, whatever). In that sense your example does not apply; there are many different kinds of suspension, but all understood, designed for different conditions to scientific basics, etc. I do not believe they would put a vehicle out with e.g. a dangerous suspension just because someone liked it.
A more expensive transformer because someone liked it? There you may pronounce me off-track! But then the (trusted) manufacturer must not proclaim that it is "better", suggesting that the unsuspecting customer should have it.
To try to be brief: There is a difference between not understanding how something can work, and understanding that it cannot work, despite perceptions. I repeat: Scientists do not know everything, but we know certain things (thus implying that it is possible to differentiate between the right and the wrong explanation of how it works or that it will work).
Your footscript by the well-known Gide is worth a thought. I would have said "be sceptical re some who "found" the truth". Otherwise none of us would have been able to communicate here, fly in aircraft, take medicines ... you name it.
Regarding transformers, I cannot accept your pronouncement "apparently nobody understands" (I take it this was re silver wire in transformers). In fact, we understand exactly how transformers work. New materials as yet unknown might someday come along to advantage, but silver is not new; we also understand it's properties.
But what is also understood but amazingly ignored in too many audio arguments, is that human hearing is also understood to the extent that it is capable of misjudgement, especially in the presence of expectation! There is no shame there either, it has been medically researched to death (oops, not a pun). Not to open a new topic, but abundant tests have shown that one can hear the same effect one moment and not the next.
To conclude (I see the yellow card's top already!): What is clear here is that there is no principle on which the use of silver wire can be justified. To put it bluntly: It is not that we do not know how it can be; I am afraid that we do know that it cannot be. And to glibly pronounce that scientists "do not know" everytime someone reports a perception however honest, is with all rerspect a bit stiff.
I have seen no proper test justifying the pro-silver stance outside the borders of established hearing limitations. Until I do, I cannot see that extra cost toward such practice is justified. As also said previously, I don't regard it as a grave matter compared to what else boils on the audio stove, only that it smacks of misleading practice to advocate this on the grounds that it is justified. Sorry.
[I would add in the interest of geniune respect to all, that I am not denigrating particular individuals' hearing. I have experienced this difference in hearing tests myself although my hearing was quite acute in younger days, as have dozens of other reliable test subjects.]
Kind regards
We are going quite off-topic and I can feel a moderator fingering a yellow card somewhere, but I hope a last commentary on this subject can slip in.
I think we are on slightly different tracks, even though toward the same goal. Your example is taken, but a manufacturer will not (I hope!) design "what the customer wants" if it violates principles to the extent that the customer is mislead in the broadest sense of the term (dangerous practice, unnecessary high cost, whatever). In that sense your example does not apply; there are many different kinds of suspension, but all understood, designed for different conditions to scientific basics, etc. I do not believe they would put a vehicle out with e.g. a dangerous suspension just because someone liked it.
A more expensive transformer because someone liked it? There you may pronounce me off-track! But then the (trusted) manufacturer must not proclaim that it is "better", suggesting that the unsuspecting customer should have it.
To try to be brief: There is a difference between not understanding how something can work, and understanding that it cannot work, despite perceptions. I repeat: Scientists do not know everything, but we know certain things (thus implying that it is possible to differentiate between the right and the wrong explanation of how it works or that it will work).
Your footscript by the well-known Gide is worth a thought. I would have said "be sceptical re some who "found" the truth". Otherwise none of us would have been able to communicate here, fly in aircraft, take medicines ... you name it.
Regarding transformers, I cannot accept your pronouncement "apparently nobody understands" (I take it this was re silver wire in transformers). In fact, we understand exactly how transformers work. New materials as yet unknown might someday come along to advantage, but silver is not new; we also understand it's properties.
But what is also understood but amazingly ignored in too many audio arguments, is that human hearing is also understood to the extent that it is capable of misjudgement, especially in the presence of expectation! There is no shame there either, it has been medically researched to death (oops, not a pun). Not to open a new topic, but abundant tests have shown that one can hear the same effect one moment and not the next.
To conclude (I see the yellow card's top already!): What is clear here is that there is no principle on which the use of silver wire can be justified. To put it bluntly: It is not that we do not know how it can be; I am afraid that we do know that it cannot be. And to glibly pronounce that scientists "do not know" everytime someone reports a perception however honest, is with all rerspect a bit stiff.
I have seen no proper test justifying the pro-silver stance outside the borders of established hearing limitations. Until I do, I cannot see that extra cost toward such practice is justified. As also said previously, I don't regard it as a grave matter compared to what else boils on the audio stove, only that it smacks of misleading practice to advocate this on the grounds that it is justified. Sorry.
[I would add in the interest of geniune respect to all, that I am not denigrating particular individuals' hearing. I have experienced this difference in hearing tests myself although my hearing was quite acute in younger days, as have dozens of other reliable test subjects.]
Kind regards
well, silver is meant to be 6%??? more conductive than copper.
so if we use a different kind of wire, aluminium or some other less conductive, hopefully around 6%, surely cu over that will give the same improvement silver has over copper, too, however that's not been verified either.
indeed dynaudio use aluminium in its speaker coils, and that has never been criticised on sonic grounds, dynaudio speakers are excellent sounding indeed.
The only way to really do it, is to have 2 identical transformer cores, with the same no. of turns, same gauge wires, but one of silver and one of copper, and listen. That's the only way to solve the debate.
Scientists/engineers more correctly, design to the maths, but there is no real correlation yet between measurements, hard scientific proofs, and subjective sound quality as heard by a listener, indeed that varies a bit from one to another, too.
What is strange and disturbed scientists, if you read the rdh 4, is that they say back in the 1930s, listeners preferred certain kinds of distortion better than what they call 'fidelity' or objective standards of low distortion.
Indeed, if we accept we like tubes, we try to give various reasons, for eg. xover distortion in semiconductors, high feedback, now xover distortion can be rendered negligible, 0.001%
and we actually explain we like tubes by perhaps their combination of distortion spectra, eg 2nd and 3rd harmonic.
so, we thus admit we prefer measurements which are less than optimial, so in this instance we see a reversing of that for makers own conveniences...ie silver measures better so sounds better.
sounds a bit like twisting things to suit own agendas to me, as its expensive so they can get away with charging so much more.
(ahh but to get the best out of silver, you need the best cores....ie nickel, cobalt, specially treated by which we charge even more, and have to be hand wound, etc...)
sound familar? spend more and more....indeed, they say also, just judge us by the sound...ie we have no idea or explanation why.
if you spend that much, you want some kind of scientific rigour, or else they look like amateurs who have no clue.
so to boil it down...
objective...scientific fact.
subjective...ones own experience.
there is no real correlation apart from a little that links object to subject, thus what one hears is in ones own opinion, one may like one better than another which is fine
.( and one will strongly gravitate to what you know as expensive, for eg. if you knew it was silver and $5000 and another copper and $200 then the chances are you'd prefer the expensive one, esp. if you were given it)
thus is it a universally acknowledged truth that silver sounds better?
sound is sensory, subjective, and is in ones own opinion, and in the absence of facts, anything can and does go.
and as they are grasping at straws to explain why silver is better, they have no idea why, it is case unproven, no proof, no objective fact.
so in other words until that time comes, it is marketing sales talk and should be treated with suspicion.
A better way to do things if poss., is try to find the effect such electrical measurements have on the actual sound waves and model the design of the ear, and what the person is hearing in his head. Then we may come to some conclusion about how these electrical phenomena affect sound, rather than measure the electrical, measure what effect they produce on what is heard, by measuring the acoustic
conclusion to all this, scientists/engineers actually pretty well understand their subject and the mechanisms involved in design, however, to attempt to link that to the little understood what an individual perceives is futile at best, and is indeed exploited by marketing, which relies on hyperbole, hype, exaggeration at best, lies at worst.
so if we use a different kind of wire, aluminium or some other less conductive, hopefully around 6%, surely cu over that will give the same improvement silver has over copper, too, however that's not been verified either.
indeed dynaudio use aluminium in its speaker coils, and that has never been criticised on sonic grounds, dynaudio speakers are excellent sounding indeed.
The only way to really do it, is to have 2 identical transformer cores, with the same no. of turns, same gauge wires, but one of silver and one of copper, and listen. That's the only way to solve the debate.
Scientists/engineers more correctly, design to the maths, but there is no real correlation yet between measurements, hard scientific proofs, and subjective sound quality as heard by a listener, indeed that varies a bit from one to another, too.
What is strange and disturbed scientists, if you read the rdh 4, is that they say back in the 1930s, listeners preferred certain kinds of distortion better than what they call 'fidelity' or objective standards of low distortion.
Indeed, if we accept we like tubes, we try to give various reasons, for eg. xover distortion in semiconductors, high feedback, now xover distortion can be rendered negligible, 0.001%
and we actually explain we like tubes by perhaps their combination of distortion spectra, eg 2nd and 3rd harmonic.
so, we thus admit we prefer measurements which are less than optimial, so in this instance we see a reversing of that for makers own conveniences...ie silver measures better so sounds better.
sounds a bit like twisting things to suit own agendas to me, as its expensive so they can get away with charging so much more.
(ahh but to get the best out of silver, you need the best cores....ie nickel, cobalt, specially treated by which we charge even more, and have to be hand wound, etc...)
sound familar? spend more and more....indeed, they say also, just judge us by the sound...ie we have no idea or explanation why.
if you spend that much, you want some kind of scientific rigour, or else they look like amateurs who have no clue.
so to boil it down...
objective...scientific fact.
subjective...ones own experience.
there is no real correlation apart from a little that links object to subject, thus what one hears is in ones own opinion, one may like one better than another which is fine
.( and one will strongly gravitate to what you know as expensive, for eg. if you knew it was silver and $5000 and another copper and $200 then the chances are you'd prefer the expensive one, esp. if you were given it)
thus is it a universally acknowledged truth that silver sounds better?
sound is sensory, subjective, and is in ones own opinion, and in the absence of facts, anything can and does go.
and as they are grasping at straws to explain why silver is better, they have no idea why, it is case unproven, no proof, no objective fact.
so in other words until that time comes, it is marketing sales talk and should be treated with suspicion.
A better way to do things if poss., is try to find the effect such electrical measurements have on the actual sound waves and model the design of the ear, and what the person is hearing in his head. Then we may come to some conclusion about how these electrical phenomena affect sound, rather than measure the electrical, measure what effect they produce on what is heard, by measuring the acoustic
conclusion to all this, scientists/engineers actually pretty well understand their subject and the mechanisms involved in design, however, to attempt to link that to the little understood what an individual perceives is futile at best, and is indeed exploited by marketing, which relies on hyperbole, hype, exaggeration at best, lies at worst.
Wait a minute......if you are trying to out-rule copper by using silver then one has a long way to go, even by starting at the LS and all those crossover chokes. The law of diminishing returns prevails i.e total waste of time. And to cap it, all those soldered joints which have even a higher resistance.
My question is what is one trying to achieve, over-improving improving broadcast quality ?
richj
My question is what is one trying to achieve, over-improving improving broadcast quality ?
richj
lt cdr data said:
I would quibble that not factoring silver's better conductivity presumes it's all floobie dust. A better way is to use its advantage to reduce turns and/or guage, then compare.
Rich, I spent most of yesterday with headphones on, piece by piece removing ceramic caps from a recently aquired Scott LT-110B tube tuner. Yesterday's full day listening to off-air signals makes 'broadcast quality' today's oxymoron.
that's a very good point, rich, yes if you do it, you have to do the whole lot, resitors, caps, wires, terminals, transformers, speaker cables, insider speakers, voice coils...
but oh dear, the inside of the tube isn't silver...ah well, shucks
guess what? mucho deneiro....and that's what companies want, profit.
if you reduce turns or guage, you risk changing other parameters, layers, inductance, capacitance, impedance, all which affect frequency response, so you have to use identical for each
but oh dear, the inside of the tube isn't silver...ah well, shucks
guess what? mucho deneiro....and that's what companies want, profit.
if you reduce turns or guage, you risk changing other parameters, layers, inductance, capacitance, impedance, all which affect frequency response, so you have to use identical for each
The only real way to excellence performance at a price is to find an output transformer which has the highest bandwidth available and designed with is properly balanced windings and then design a tube circuit around it i.e ones own nirovana. My first step is to ban electrolytics in the front end signal path, but alas......ther'e fitted in every bit of consumer equipment one buys.
By the way, coming back from a night out in the town, ones ears hear totally different to when you started out. So why all the trouble ?
richj
By the way, coming back from a night out in the town, ones ears hear totally different to when you started out. So why all the trouble ?
richj
richwalters said:
Especially after the wife has boxed them for coming in late with unknown lipstick on your collar. (
literally) Vaguely back to topic, I think we know that in output transformers, quite the most distortion is produced by the core. (That further reduces the contribution of whatever wire.) Somewhere it was stated that OPTs down to 0,3% distortion was designed (perhaps RDH) - I would like to know how (asking, not doubting).
If the topic can be kept wide, it brings us to the advantage of toroids, which I have never used so far simply because I do not know how to calculate parameters for a randomly wound OPT. (I also do not have a manufacturer handy close-by; imports are expensive for us.) The articles by Van de Veen is interesting if somewhat promotional. Still building tube amplifiers and having designed my own OPTs over decades (conveniently wound locally) I would appreciate some comment here, especially from experience.
Or perhaps a MODERATOR would like to move the last few posts to a new thread on output transformers? (Did we have such a thread before?)
Regards
There are several winding houses in the UK which have their own ideas on winding techniques with output transformers. The EI construction seems most popular and easiest. I shan't name # names as this would be seen as sales bias.
Most are expensive, well made balanced designs and use multisections based on designs by Williamson and Partridge designs. All these were mathematically worked out and not guessed that the expected leakage inductance was predicted graphically with fair accuracy.
Of all the designs I've used, the toroid although being best on paper often comes up as one of the worst if pile wound. The winding constructions have to be very well designed by a expert winder. I'm staying with standard EI.
richj
Most are expensive, well made balanced designs and use multisections based on designs by Williamson and Partridge designs. All these were mathematically worked out and not guessed that the expected leakage inductance was predicted graphically with fair accuracy.
Of all the designs I've used, the toroid although being best on paper often comes up as one of the worst if pile wound. The winding constructions have to be very well designed by a expert winder. I'm staying with standard EI.
richj
hi johan, rdh4 is wonderful, but takes a lot of getting your head around.
core distortion mostly comes when it saturates, ( just like with valves, you get more distortion as the signals get bigger, as it gets into the non linear part of the characteristics, and at extremes, clipping, core dist. is asking the core to carry more flux than it can, so its magnetic clipping)
the classic equation.
B = V rms x 10 ^8 / 4.44 x frequency x area x No of turns.
B is limit of magnetic flux to cause saturation, typically, 16,000 for M6
so we can limit saturation and core distortion by VERY conservative design,
viz, set B for 12,000 gauss.
Make V smaller
make freq. bigger
area bigger
and no of turns bigger.
usually, a few are set, eg 12,000 gauss, core area, frequency at less than 20 hz, so you get no of turns to give that gauss.
so you see that core distortion and saturation is a function of frequency, volts, area and no of turns, and you can derive other relations between them, too.
so wire in essence does still contribute to core dist. as the no. of primary turns
that's how to do it and keep core dist. to a minimum.
so for an excellent push pull transformer,
no of turns = root power x root primary Z x 10^8/ 4.44 F x A x B
set F to 20 hz say, perhaps less
Area = 4 x root power
B =12,000 gauss.
you get Turns = root primary Z x 1.10^8 / 4.44 x 20 x 4 x 12,000
no primary turns = 23.6 root of primary Z, that will work very conservatively and that relation holds very well indeed for all push pull tx's, as long as you make the core area 4 x root power (at clip, in cm squared)
plug the parameters in to see how I have derived that, it works!! you can alter some parameters at wish to get a different figure, freq., gauss, but keep area the same
you could go really stupid and set f to 10 hz, but 15-20hz is optimal
as to how much core dist. those parameters will give, no idea have to read rdh4 again.
I am working on derving all the other important relations for transformers, if anyone is interested in the future, its quite challenging tho'.
are you talking of sowter, rich? its ok to name them I hope, and others, just saying who iyho do things well, nothing wrong with that I don't think.
core distortion mostly comes when it saturates, ( just like with valves, you get more distortion as the signals get bigger, as it gets into the non linear part of the characteristics, and at extremes, clipping, core dist. is asking the core to carry more flux than it can, so its magnetic clipping)
the classic equation.
B = V rms x 10 ^8 / 4.44 x frequency x area x No of turns.
B is limit of magnetic flux to cause saturation, typically, 16,000 for M6
so we can limit saturation and core distortion by VERY conservative design,
viz, set B for 12,000 gauss.
Make V smaller
make freq. bigger
area bigger
and no of turns bigger.
usually, a few are set, eg 12,000 gauss, core area, frequency at less than 20 hz, so you get no of turns to give that gauss.
so you see that core distortion and saturation is a function of frequency, volts, area and no of turns, and you can derive other relations between them, too.
so wire in essence does still contribute to core dist. as the no. of primary turns
that's how to do it and keep core dist. to a minimum.
so for an excellent push pull transformer,
no of turns = root power x root primary Z x 10^8/ 4.44 F x A x B
set F to 20 hz say, perhaps less
Area = 4 x root power
B =12,000 gauss.
you get Turns = root primary Z x 1.10^8 / 4.44 x 20 x 4 x 12,000
no primary turns = 23.6 root of primary Z, that will work very conservatively and that relation holds very well indeed for all push pull tx's, as long as you make the core area 4 x root power (at clip, in cm squared)
plug the parameters in to see how I have derived that, it works!! you can alter some parameters at wish to get a different figure, freq., gauss, but keep area the same
you could go really stupid and set f to 10 hz, but 15-20hz is optimal
as to how much core dist. those parameters will give, no idea have to read rdh4 again.
I am working on derving all the other important relations for transformers, if anyone is interested in the future, its quite challenging tho'.
are you talking of sowter, rich? its ok to name them I hope, and others, just saying who iyho do things well, nothing wrong with that I don't think.
here's one, for a single ended tx, Lp = Z /126
which leads to the air gap size which has been derived and simplified.....and no, its not just as simple as plugging numbers in.
what's interesting, is that you can derive the equations to be dependant on one or two parameters...
core area = function of power
precisely, 4 root P
turns = function of impedance
inductance= function of impedance...
or by substituting root p = v/ root z
you can get those 3 as a function of Z alone.
core area thus 4 x V / root Z
ad. inf.
another is I dc max = Turns x Area.10^-8 x B / L
which leads to the air gap size which has been derived and simplified.....and no, its not just as simple as plugging numbers in.
what's interesting, is that you can derive the equations to be dependant on one or two parameters...
core area = function of power
precisely, 4 root P
turns = function of impedance
inductance= function of impedance...
or by substituting root p = v/ root z
you can get those 3 as a function of Z alone.
core area thus 4 x V / root Z
ad. inf.
another is I dc max = Turns x Area.10^-8 x B / L
whic you can boil down to a function of I rms
I dc max = .95 I rms
however, its futile, as they are only for M6 IE core, and depend on the values given before, and I ain't going to be building my own tx's, so you may as well go through the full equations instead of the short cuts ( there may be errors, too as my maths is rusty, but its been an interesting math excercise over the past few days)
having said that, those silvery chrome mars tx's appear to be well designed, I popped some parameters into one and it seemed to hold up well.
for the core size, I calculated no. of turns, and it turned out the inductance and B dc worked out spot on.
so it appears that some chinese stuff is ok, which is where the thread started
I dc max = .95 I rms
however, its futile, as they are only for M6 IE core, and depend on the values given before, and I ain't going to be building my own tx's, so you may as well go through the full equations instead of the short cuts ( there may be errors, too as my maths is rusty, but its been an interesting math excercise over the past few days)
having said that, those silvery chrome mars tx's appear to be well designed, I popped some parameters into one and it seemed to hold up well.
for the core size, I calculated no. of turns, and it turned out the inductance and B dc worked out spot on.
so it appears that some chinese stuff is ok, which is where the thread started
<<Quoted viz, set Bmax for 12,000 Gauss >>. or 1.2T (Si units) This is far too high ..I specify around 0.7T or 7000 Gauss. Why ? explanation....
For closed core types Intermodulation and harmonic thd results from non-linearity between magnetising current and magnetic field in the transformer core. Thd is always present but can be reduced by keeping Bmax low for standard M6 sheet. So that conflicts with number of turns to produce L and up goes the leakage inductance and it's the designers job to make compromises out of all conflicts.
Harmonic thd can also occur due to too high resistance primary but nodays this is very rare as most designers try to fill bobbin window with upped wire dia on both prim and sec.
The effect with too high Bmax will introduce thd at the LF end at specified cut-off frequency. As in an earlier thread this approach to near saturation will hammer the output tubes (as permeability crops)and is bad practice, but in a more subtle way as the Bmax increases to just under cutt-off it introduces more 2nd harmonic thd which creates more artifical bass.
For standard p-p I aim for 1% thd at LF cutoff at designed power spec.
Certain console manufacturers did just this 2nd harmonic trick by using input transformers close to low end saturation.
richj
For closed core types Intermodulation and harmonic thd results from non-linearity between magnetising current and magnetic field in the transformer core. Thd is always present but can be reduced by keeping Bmax low for standard M6 sheet. So that conflicts with number of turns to produce L and up goes the leakage inductance and it's the designers job to make compromises out of all conflicts.
Harmonic thd can also occur due to too high resistance primary but nodays this is very rare as most designers try to fill bobbin window with upped wire dia on both prim and sec.
The effect with too high Bmax will introduce thd at the LF end at specified cut-off frequency. As in an earlier thread this approach to near saturation will hammer the output tubes (as permeability crops)and is bad practice, but in a more subtle way as the Bmax increases to just under cutt-off it introduces more 2nd harmonic thd which creates more artifical bass.
For standard p-p I aim for 1% thd at LF cutoff at designed power spec.
Certain console manufacturers did just this 2nd harmonic trick by using input transformers close to low end saturation.
richj
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