Torroidal Transformers vs. transformers

Discussion in 'Amps and Cabs' started by bluessyndicate, Feb 8, 2005.

  1. bluessyndicate

    bluessyndicate Member

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    You hear so much talk about amp designs and how the transformer is the heart of the amp design and contributes to feel etc....

    I've also learned that torroidal transformers are superior for noise reduction and as a result are used for many low noise studio applications....I know my Mesa Boogie Triaxis used one and it was very quiet....

    I've read that most amp designers pass on torroidal transformers due to their cost being roughly twice as expensive as the typically used transformers...

    my question...

    is cost the primary concern...can one find torroidal transformers that give the same result as other highly prized iron? I.e....if money were not a constraint, would torroidal transformers be the way to go?...or would designers opt for other more traditional transformers due to superior sag/feel/performance?


    Thanks!
     
  2. scottcrud

    scottcrud Member

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    bump, because I'd like to hear some amp builders thought on this as well.
     
  3. JDouglee

    JDouglee Member

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    John Suhr has some interesting insight on this very topic. He's been swapping out toroidal transformers for more Marshall-esque ones in people's CAE 3+ preamps. A warmer, more "amp like" sound being the result.
     
  4. scottcrud

    scottcrud Member

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    so are torriodal trannys thought to be brighter sounding? I know the Laneys that use them certainly are bright, but that may be how they're designed.
     
  5. 908SSP

    908SSP Supporting Member

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    Make sure we are talking about the same thing the toroidal transformers are used for the "power" transformer not the output transformer. The power transformer should have some effect on aspects like sag but tone? I can't see that, it supplies voltage to the components NO signal goes through the power transformer. Anyway Maven Peal uses one in his amps and they are dead quiet no power supply hum. Since his power supply is designed different then most with all kinds of controls incorporated that the typical amp doesn't use to allow for the adjusting of both wattage and sag his is not typical of what you might find in other amps. Power conditioners and cleaners the expensive $500 and up ones use toroidal transformers in them.
     
  6. bluessyndicate

    bluessyndicate Member

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    Yeah, where is Doug and Randall and Joe/Bill and Andy and the rest of the cast?

    :confused:
     
  7. ericb

    ericb Silver Supporting Member

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    I've only played 2 amps with Torroidal Transformers.. They both were supposed to be DEAD QUIET according to every other user of the 2 brands and the amps. I found both to be much noiser than any of my other amps .. Not in HUM , but in susceptability to schreeching, and extraneous noise etc.. Much more susceptibility to pickup noise . Was it something else with those amps? I don't know.. I still own one and it has incredible tones but it's noisy.. The other was a demo , and was too noisy for the gain levels it produced for me. I'm not going to name either amp or brand, but it was/is a mystery to me why if they're supposed to be so quiet, they're noisier for me

    ERIC
     
  8. gregc

    gregc Member

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    James Demeter uses a Torroidal Tranny in the power supply of the TGA/3 amp for low noise. I believe size & light weight are also benefits. They get pricey to my knowledge.
    gregc
     
  9. Mark Kane

    Mark Kane Silver Supporting Member

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    The Ganesha I had was dead quiet, the Egnator TOL 100 was not.
     
  10. ericb

    ericb Silver Supporting Member

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    my tga3 with the torroidal is noisy as hell. My tga2 with a regular xformer is DEAD QUIET.
    There ya go?? ;)

    ERIC
     
  11. Fuchsaudio

    Fuchsaudio Member

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    I respect John Philips, and truly appreciate all he contributes (and all the typing time he saves me here) LOL. but Hombre, let's agree to disagree and kick this around a bit shall we ?

    Toroids actually don't offer any real substantial benefits (that you could take advantage of) over a standard e/i core transformer in an MI amplifier. A properly designed (and layed out) amplifier (and transformer design) can be made just as quiet (maybe moreso) using conventional iron. A toroid doesn't offer substantially better regulation than a properly designed conventional equal, and guitar amps do actually like some power supply sag anyway. I explored this during a design project for another manufacturer, as well as during R&D for our own products. Were there a benefit, I would have used a toroid. I wanted to "pull out all the stops", my vendor convinced me to not bother with a toroid power tranny.

    Yes, they can sometimes offer a smaller radiated magnetic field, but if you design the amp so you don't put tubes or reverb pans near the transformer (who would anyway ?), it doesn't matter. So even if there were a benefit to the smaller magnetic field, but you designed an amp with dirty power supplies and/or ground loops, you wouldn't gain anything from your wonderful toroid.

    Stand in front of a Fender twin, pro, or deluxe with a P-90 or strat sometime, and you'll see a healthy radiated magnetic field (right behind the pilot light), but the amp itself doesn't get hurt by it.

    You can also often run into problems with the mounting hardware forming a magnetic "short" through the middle of the troroid core if not insulated and/or non ferrous. In solid state amps, they can be a space saver however. Other negative: A toroid core is a ferrite casting of metal and a binder, not a lamination of layers of metal. It get's dropped, it breaks, bye-bye. A stack of steel laminates can shift, but usually survives being pounded a lot more than a toroid core does.

    Toroid output transformers are a rare breed and actually bring with them a more difficult design task, as the windings must deal with the curvature of the core, (as if output transformers aren't complex enough beasts to design properly already) ! They also require specialized winding equipment as well.

    I explored power toroids early-on with Sergio at Mercury Magnetics, (as well as some other vendors we use) who eventually convinced me there was really no practical benefits for my application. I feel he was correct. Through proper layout, grounding and quiet power supply sources, we have '0' hum issues. We burn our amps in "dimed" through 4" car speakers. All gains up, all boosts on, and it sounds like an ocean on a busy day in the shop. The ocean does not hum, nor do our amps. BTW: Mercury does make toroids for other customers where specific applications warrant it, so it wasn't an issue of his not being able to produce anything we wanted.

    I think sometimes toroids offer some "curbside appeal" to those who think "wow a toroid" it must be hi-tech.

    Carry-on kids. :D
     
  12. bluessyndicate

    bluessyndicate Member

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    Thanks Andy, great information making some great points in support of traditional transformers... help me clearly understand your quote above...is this to say that torroidal transformers do not offer as much power supply sag? I like sag...on guitar amps at least....made my grandma look scary..but that's another thing...

    :D :eek: ;)

    And while your at it, what's your take on my MU Amplifiers question? MU Mu MUUUUUUUUU
     
  13. Roccaforte Amps

    Roccaforte Amps Member

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    Torroidial's are way more efficient,
    so it takes a much smaller
    one to produce the same results,
    power transformers that is.

    I've only tried two outputs,
    they were too HiFi for my liking,
    but that doesn't mean they're bad.
    Like anything else high tech,
    it always goes HiFi before
    drifting into the MI market.

    High cost is another issue,
    but word has it that they're
    starting to come down in price.

    The future well tell where it goes.

    If I can get them to produce
    the same results I'm getting now,
    I would switch instantly.
    They certainly reduce the weight.
     
  14. Fuchsaudio

    Fuchsaudio Member

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    Call Sergio at Mercury, then call me. You might change your mind. ;)
     
  15. KevinOConnor

    KevinOConnor Member

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    Hi Guys!

    Most of Any's commenst above are correct, except for the description of the core. What he described is a ferrite core used in tiny high-frequency transformers.

    Cores for power toroids are a spiral wound strip of typical transformer core steel. The ends are welded, the spiral annealed and then covered in epoxy. Then the core goes to the wrapping and winding machines to become a transformer. For a given power throughput, a toroidal transformer is a half to two-thirds the size of a square device. If you pot this, then there is no weight savings. The 300-400W bass amps with toroidal OTs and PTs use them strictly for weight savings.

    Stray field from a toroid is about 3% that of an equivalent EI unit. This field radiates off at a predictable angle around from the primary lead-out, which makes orienting the PT very easy. PTs in my amps have a core band, which is an unusual feature for a toroid, but it helps contain some of that stray field.

    It also helps to use a larger core than is needed, but most designers specifying a toroidal PT do so to save space. This decision cripples noise performance, regulation and line noise suscpetibility (rather, the rejection of same). Claimed "narrow band" PTs use a common winding technique to limit high frequency response. However, good circuit design and simple filter amendments (as seen in TUT3) will reduce noise coupling between windings and into the circuit, and are applicalbe to EI PTs.

    Personally, I would use toroidal PTs even if the only demonstratable improvement is less proximity effect for buzz with your guitar. There are other benefits: reduced mechanical noise (which is a big problem in Marshalls: Owe Johnson reduces this by raising the PT off the chassis using extra nuts on the mounting bolts), reduced interference into other equipment, reduced interference into the OT, reduced susceptibility to induced hum.

    By the way, the only two things that can fix proximity effect with your amp are space and mu-metal. One is cheap, the other is not.

    As far as toroidal OTs go, they are much cleaner because they lack the types of distortion intrinsic in EIs. So, that may be perceived as brighter or simply as there being something missing. You can compensate for this by adding a tube stage or using ceramic coupling caps somewhere in the circuit. To drop one into an amp, will change the tone the same as replacing the electrolytics with plastics.

    For the sounds I like to be able to get from my amps, I prefer not to have restrictions imposed by the OT. Therefore, I use what most players would term "hifi" OTs. In this decision, toroidal OTs are fine, and we'll be using them in the new version of the Studio amp this year. Tone creation comes from many places, and I have decided to get tone from other places than the OT. Other designers believe a specific tube set demands a specific OT, and that is the aesthetic they follow, which is fine for them.

    Generally, although the intuitive needs for hifi and MI are different, the perceptions of players and listeners is really the same. Both are choosing equipment for subjective goals of enjoying what they are listening to, and that means going with whatever sounds good to them individually. Specs and performance statistics have as much meaning and relevence as the adrenalin rush or leaping out of your seat to dance. Most people who reject specs completely, often do not understand anything about what they hear.

    However, even with respect for specifications, you have to train your ear to _know_ what you are hearing. Then you can acknowledge your own subjective impression and hopefully accept the fact that what you "like" does not match what you "should like". It is perfectly okay to like what you like, just don't insist that everyone else should like it, too.

    So, toroids are cool. EIs are cool. Use what YOU think is cool.
     
  16. bluessyndicate

    bluessyndicate Member

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    Also great info Kevin....

    Comment on how you think they feel and sag in comparison?
     
  17. KevinOConnor

    KevinOConnor Member

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    Hi Guys!

    Sag is going to be the same as with any PT: if the PT is just adequate to supply the amp, there will be sag; if the PT is much more ample, then less sag; if it is wholly inadequate, then tonnes of sag.

    If by "feel" you mean the specific distortions added by the OT, then there are actually two issues to consider. The first, is stated in my previous post, that toroids are inherently cleaner and add less THD than EIs. The second relates to bandwidth.

    You can design any OT to have whatever bandwidth you need or want. As most everyone knows, MI OTs _require_ less bandwidth than hifi due to the narrow range of fundamental frequencies produced by a guitar. The amp adds many harmonics to those from the instrument, some of which are subharmonics that can cause the OT to distort at low frequencies, with the resultant distortion harmonics in the upper bass and mids.

    If this same amp had a hifi OT, the subharmonics from the elctronics would come through as low notes, with less distortion added to the higher frequencies. Because harmonics can imply lower notes, and imply stronger lower notes than are present, a bandwidth limited OT might sound like it has more bass than one that is not bandwidth limited. There's an irony for you!

    So, the differences between an OT toroid and EI "feel" is often more related to the difference between bandwidth. Those can exist within both forms; you can easily spec a toroid to have similar bandwidths as you are used to from EIs in MI.
     
  18. aortizjr

    aortizjr Member

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    Sorry for digging up a thread that is over a year old. But hey you can't accuse me for not using the search function :)

    WIth Torroidal transformers in a tube amp, would there be significant weight savings? Particularly in the 50W to say 100W range.

    Is the cost difference still pretty high? Even Behringer uses Torroidal transformers in their stuff.
     
  19. bluessyndicate

    bluessyndicate Member

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    bump for good use of the search function :AOK
     
  20. matte

    matte Senior Member

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    WFCs? My TOL has one and it sounds amazing. My Uberschall doesn't and it sounds amazing too. The better the player the less any of this **** matters. I sound like me, regardless of whether I'm playing through an Uber, an Elmwood, a Bruno Super 100, etc.

    More rock, less talk.
     

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