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    EI vs. Toroidal transformers

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    JunkyJan

    Posts : 103
    Join date : 2008-12-09
    Location : BC, Canada

    EI vs. Toroidal transformers

    Post by JunkyJan on Wed Sep 28, 2016 1:48 pm

    Good day gents (long time no speak!)

    I have been wondering about the fervour around toroidal transformers in high-end audio. In my youth I was taught in technical school that toroidal transformers have a place in the universe (that being dictated by space and weight requirements - lower profile & lighter than EI etc) but also that the disadvantages outweigh the advantages... The thinking at the time being that a well-implemented EI transformer will always outperform a well-designed Toroidal. I looked at it again recently and came across this super-interesting article: http://www.soundstage.com/maxdb/maxdb071998.htm

    Ps. My Mark III and ST-70 amps are still going strong - built from Bob's kits - my Mark IIIs are now on their 3rd or 4th set of tubes, cant believe it's been 8 years! ( http://dynacotubeaudio.forumotion.com/t514-dynaco-mark-iii-build and http://dynacotubeaudio.forumotion.com/t17-kicking-it-off-here-s-mine )

    Peter W.

    Posts : 152
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: EI vs. Toroidal transformers

    Post by Peter W. on Wed Sep 28, 2016 3:20 pm

    [quote="JunkyJan"]Good day gents (long time no speak!)

    I have been wondering about the fervour around toroidal transformers in high-end audio. In my youth I was taught in technical school that toroidal transformers have a place in the universe (that being dictated by space and weight requirements - lower profile & lighter than EI etc) but also that the disadvantages outweigh the advantages... The thinking at the time being that a well-implemented EI transformer will always outperform a well-designed Toroidal. I looked at it again recently and came across this super-interesting article: http://www.soundstage.com/maxdb/maxdb071998.htm

    There are some pretty large discrepancies in the article, at least as it applies to residential power  the US.

    a) US residential power is, mostly, split-phase 120/240 AC, 60Hz power. Not two-phase. There is some 2-phase, 4-wire power still extant, mostly in Philadelphia and Baltimore, but that is 180-degree power designed, far back in the day, to start elevator motors before 3-Phase Delta was common. To this day, other than shaded-pole induction motors, most single-phase AC motors require additional circuitry to start (motor start and motor run capacitors for instance). If they were 120-degree two-phase motors, this would not be an issue - but load-balancing would be.

    b) This discrepancy demonstrates a fundamental misunderstanding of how a single-phase transformer works, and how "DC Offset" actually works. If there is DC offset, this will not be because of any unbalance between phases - as there is only one. The primary reason for balancing loads in a single-phase system is to reduce demand, and reduce the load on the neutral (ground). A properly balanced load under ideal conditions puts no load on the neutral. But, other than the potential to overheat the neutral from the panel to the 'pole' there are no issues with DC offset in a split-phase 120/240 system. Put another way, at the wallplate, the individual load does not understand, or care, whether the supply is 'balanced' or not.

    Now, as to my opinion on conventional vs. toroidal transformers, I have none. But when I see some basic lack of understanding, I start to question the entirety of the premise and would tend to discount such a source. The Luddite in me leans towards 'old technology', but that is personal prejudice, not formed, fact-based opinion. I am entirely open to well supported opinions based on actual independently verifiable facts.

    JunkyJan

    Posts : 103
    Join date : 2008-12-09
    Location : BC, Canada

    Re: EI vs. Toroidal transformers

    Post by JunkyJan on Wed Sep 28, 2016 5:01 pm

    Peter W. wrote: Now, as to my opinion on conventional vs. toroidal transformers, I have none. But when I see some basic lack of understanding, I start to question the entirety of the premise and would tend to discount such a source. The Luddite in me leans towards 'old technology', but that is personal prejudice, not formed, fact-based opinion. I am entirely open to well supported opinions based on actual independently verifiable facts.
    [/quote]
    Nope, I do think you are way over-critical. The author isn't saying anything in regards to Toroids vs EI types that you cannot go and confirm in any Electrical Design 201 textbook. As to his misunderstanding of split-phase vs. two-phase, I would have allowed some leeway in someone's attempt at explaining things to a lay audience. Would be impossible to vote for ANY politician or pary in ANY country otherwise. Wink

    Peter W.

    Posts : 152
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: EI vs. Toroidal transformers

    Post by Peter W. on Wed Sep 28, 2016 8:27 pm

    JunkyJan wrote:
    Peter W. wrote: Now, as to my opinion on conventional vs. toroidal transformers, I have none. But when I see some basic lack of understanding, I start to question the entirety of the premise and would tend to discount such a source. The Luddite in me leans towards 'old technology', but that is personal prejudice, not formed, fact-based opinion. I am entirely open to well supported opinions based on actual independently verifiable facts.
    Nope, I do think you are way over-critical. The author isn't saying anything in regards to Toroids vs EI types that you cannot go and confirm in any Electrical Design 201 textbook. As to his misunderstanding of split-phase vs. two-phase, I would have allowed some leeway in someone's attempt at explaining things to a lay audience. Would be impossible to vote for ANY politician or pary in ANY country otherwise. Wink [/quote]

    With respect, you opened the door. My politicians tell the lies I want to hear, yours tell the lies you want to hear. That they are lying is not under discussion.

    The source you cite is nothing more than the typical politician.

    JunkyJan

    Posts : 103
    Join date : 2008-12-09
    Location : BC, Canada

    Re: EI vs. Toroidal transformers

    Post by JunkyJan on Wed Oct 05, 2016 4:22 pm

    I originally responded to your post with a mildly sarcastic but amusing reply... But then I thought about it again. I think what you are really saying equates to the following experience I had: I am an Aviation Nut (one of my many failings) and at one stage owned a book on the Mitsubishi Zero fighter plane. One evening while browsing/reading through this book, I noticed a photograph of a Ki-43 Hayabusa 'Oscar' fighter plane, with a caption that read that this is a Zero of some unknown unit. That the author of a book devoted to a certain aircraft type can make such a mistake is unthinkable to me - granted, the two planes look similar but any WW2 plane spotter would have seen the error. The author lost al my respect and faith as an authority on the subject right there and the book ended up in the recycling bin the next day.

    ...So.... Yes, I agree - I see your problem with the article now.

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