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transformerless microphone explained

Discussion in 'Microphones' started by audiokid, Oct 26, 2011.

  1. audiokid

    audiokid Staff

    What is the difference in sound between a transformer and transformerless mic. Why would someone choose to use one or the other and is there a more specific micpre that goes better with either?
     
  2. Boswell

    Boswell Moderator Distinguished Member

    You could talk all day about what a transformer does to an audio signal that's passing through it, but that approach misses the point that it's an integral part of the design of this type of mic. You couldn't, for example, connect a transformer to the output of a transformerless mic and expect it to sound like a mic that is designed around a transformer output. You could have a similar but different discussion about the difference between a transformer-input pre-amp and a non-transformer unit.

    In high-quality designs of both mics and pre-amps, it's not a question of whether the output (or input) goes through a transformer, it's whether the whole design philosophy of the unit centres around the use of a transformer. You don't just get sonic change due to the magnetisation, hysteresis and (sometimes) saturation of the iron core, you get a circuit element that is hard to replicate in any other way. This includes: voltage gain (via turns ratios), inherent a.c. coupling that avoids needing to use series capacitors to block phantom power voltage, impedance change and easy differential->single-ended conversion. The gain and impedance change was particularly important when the first stages of pre-amplification only had valves/tubes.

    Built-in microphone transformers are not the preserve of condenser mics, as even dynamic mics like the SM57 and SM58 have them. Using a transformer-based mic with a pre-amp like the API 3124+ means that the audio goes through three transformers before it arrives at the line level output socket. That route is especially good for taming slightly strident female voices. I've had people simply not believe that a particular vocal track was recorded using an SM58 taken though an API pre-amp.
     
    audiokid likes this.
  3. RemyRAD

    RemyRAD Well-Known Member

    LOL! Yup, if that transformer less sound is what you want. But you really have to know what you want. Let's face it good Transformers are much more cost intensive than a couple of little transistors. And so I believe the biggest push to go transformer less is not so much its acoustic qualities than a manufacturing expense. I would say that the transformer less group actually has a more neutral quality of sound then something specifically designed to have " a sound" of its own. So it's really more of a difference in subjective philosophy than anything else. I'm sure there are folks here to remember that numerous folks have removed their Transformers from their SM57/58's and all have noted " an improvement in the quality" of the sound in spite of the difference in output levels. So when you have those premium sounding preamps that transformer versus non-transformer becomes less of a factor than the sound of all that budget equipment sounds like. So again it comes down to the intelligent grouping of certain pieces together as basically we are all audio systems integrators. Currently I possess no transformer less microphones. Although I would consider some of the Neumann's since I've used many of the TLM series into my transformer coupled API & NEVE inputs and liked them. They are almost too pure, too clean in their lack of coloration, which is great for some things. I wouldn't turn down a couple of those if and when the opportunities arose. But I would still be plugging them into transformer coupled inputs just for that extra butter on the bread.

    I ain't got no bread
    Mx. Remy Ann David
     
  4. audiokid

    audiokid Staff

    Oooh this is interesting!

    I can see why DPA ( to name one favourite brand) designs these. Choosing the right micpre gets you closer to the precise sound, yes? Put the weight on the preamp more... get them both right and its transparent, clean and accurate. So, the transformer-less mic should be ideal for classical / acoustic music where you want a very un coloured sound?

    If the mic and the preamp add something to to sound, it could be more difficult of a match too, correct? There is more we could get into here? I'm guessing this is where you were going with this Bos and Remy? Could we expand this topic and talk about choosing and matching transformer-less Microphones to certain micpre's, why and so on?

    I found this after I posted, it fits in here well:

    http://www.dpamicrophones.com/en/Mic-University/Technology-Guide/Transformer.aspx
     
  5. RemyRAD

    RemyRAD Well-Known Member

    I think you are exactly right Chris. Although I don't necessarily consider clean transparent neutral a prerequisite for the fine arts oriented capture process. I recorded some operatic vocalists in my day who had similar qualities to certain former superstars. So in the production of their demos & concert recordings, I definitely went more retro. And retro may signify use of tube preamps and/or tube microphones, ribbon microphones even larger diaphragm dynamic microphones like the RE 20. All transformer coupled preamp mixer in/out while still utilizing modern digital & analog recorders. I mean I really don't think we would like to hear Maria Callas or Caruso on what you've described? They certainly didn't sound like what you've described that way in person. They had with depth & balls. They didn't sound clean transparent or genderless. And I think this is where the difference really lies in this statement? Are you learning about the art of recording science? Or are you learning about the art of recording? As a fabulous engineer (I am fabulous you know) I want to impart on my work how fabulous my work is as compared to how consistent each McDonald's hamburger is to each other. I mean we all love those hamburgers and we've virtually all live on those things. But you don't go out to McDonald's on your birthday unless you're under five years of age. And every superior production that you do is a birthday.

    56 two weeks ago
    Mx. Remy Ann David
     
  6. audiokid

    audiokid Staff

    Well said, but how about from an instruments POV. This is where I was thinking this knowledge is more suited or applied, yes, no?
     
  7. BobRogers

    BobRogers Well-Known Member

    Happy (belated) Birthday and many more to come.
     
  8. RemyRAD

    RemyRAD Well-Known Member

    I think we all marvel at the sound of improvements all along the way. But it's sort of like adding new substances to the periodic table. It's just another something to be utilized where needed. I really enjoy some of the sound of those new active ribbon microphones. But then they sound less like ribbons and more like condenser microphones. In a sense, a new breed. So it all is something to behold and appreciate. But if one did notice one thing about the AES show, the highest audible improvements were within old-fashioned analog circuitry coupled to their fairly average digital counterparts. I saw and heard no real advancements on the digital side. Improvements in software, sure. Improvements in digital hardware, not much. Improvements in everything analog, all over the show floor. Were any real true digital microphones displayed like 2 years a go? Nope. Everything we currently work with and use to work with is still being refined. So I'm not quite sure where the improvements need to be utilized that much? If they need to be utilized that much? Nuance differences are nice but at what price in today's economy? I seen a huge shift up in price higher than the improvements. Are these nuance differences large enough & necessary to embrace, over what we've been using the last couple of years? Or should we just embrace these items to ensure the fact that these companies don't all go out of business yet? Everybody needs to make a buck. And for a lot of us in this business for a while all know, this business is a money pit. Thankfully the younger folks and recording enthusiasts benefit most from this. Whereas professional equipment of virtually any age in the hands of professionals will always yield a first-class professional product. Of course the pricing of some of this new stuff can also be prohibitive as there was much about there as well. There are things in the scientific arena that are coming online now for the consumers because of advancements in mass automated production techniques. So while the really expensive stuff keeps getting really more expensive, the lesser expensive stuff is also further improved and also more available. I personally don't purchase a new car every two years. I get something I like and use it to its fullest. Run it into the ground. And then fix that soldering mistake.

    I wouldn't turn down a transformer less TLM Series condenser microphone. Who would? Certainly nobody in their right mind would. But in what realm of improvements are you most referring to? The transducer side? The amplification side? Or, the converter side? Which of the most important? Where can greater musicality be realized? And how is it realized? I heard some nice monitors there but I also heard some pitiful ones. And microphones are more like people and should be enjoyed for their individuality. And the electronics gets those electrons to all march to the beat of a synchronized drum. Nobody likes electronics who's footing is not in step with each other. But I really think we've reached a plateau technologically. There are no answers. Only choices. (Solaris-George Clooney)

    Thanks for the birthday greeting and I hope I see a few more unlike some of my close friends.
    Mx. Remy Ann David
     

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