tube mic pres vs solid state

Discussion in 'Pro Audio' started by Gord, Dec 7, 2004.

  1. Gord

    Gord Guest

    Hi,

    I've read a bunch of posts regarding the differences between tube and
    transistor mic preamps. Apparently, circuit design and component
    quality has more to do with the sound than the tube vs. solid state
    issue. I've even read many posts saying that there is no "tube sound".

    But I would guess that there are many well respected people out there
    who would beg to differ, (*don't* quote me on this), possibly Doug
    Fearn, Aspen Pittman, Oliver Archut, etc., who might even say that
    tubes make better preamps.

    On the other hand, there might be people out there which we all
    respect and they believe the best products are solid state preamps.

    Is there a global difference between top-of-the-line tube preamps and
    top-of-the-line solid state preamps that can be put into words? I know
    that all preamps are different, but if a recording (in my case, live
    in-the-studio local pop/rock bands) was done through a variety of
    great tube pres, ie. Vipre, Fearn, Pendulum, Tab-Funkenwerk, etc.,
    what kind of difference could I expect in my recording processes and
    finished products vs. doing the same recordings with a variety of
    great solid state preamps, ie. Neve, API, GML, Great River, etc.?

    I'm sure they'd be quite different, but how?

    Thanks,
    Gord
     
    Gord, Dec 7, 2004
    #1
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  2. Gord

    Scott Dorsey Guest

    They make different preamps. And of the three folks you list, they
    all make preamps that sound radically different than one another.
    No, the best product is the one that fits your particular application
    on a particular track on a particular song. If everybody wanted the
    same thing, they wouldn't have to make so many kinds.

    Right now, the most neutral-sounding preamps happen to be solid state
    ones, although Fred Forssell is definitely in the running with a very
    neutral tube preamp. I tend to be a fan of neutrality in preamps myself.
    Others aren't.
    Most of the preamps you describe are colored preamps, and most of them
    are designed for particular coloration. And yes, they all sound
    different. Not different enough to be religious about it, but different
    enough that if you had a varied selection, you'd want to use different
    preamps on different tracks.
    You need to listen to the Boston Pre Party CD, or to Lynn Fuston's preamp
    shootout CD.
    --scott
     
    Scott Dorsey, Dec 7, 2004
    #2
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  3. Gord

    DeserTBoB Guest

    Aspen...<snicker!> Ho boy, now THERE'S some snake oil for ya! HAR!

    dB
     
    DeserTBoB, Dec 7, 2004
    #3
  4. Gord

    Ty Ford Guest

    Define sweeter. Is it relative to salt, sour or sugar? I see sweeter too
    frequently and most of the time it seems to mean "I like it."

    I think we could all do with a little less "sweeter."

    Ty Ford



    -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
    stuff are at www.tyford.com
     
    Ty Ford, Dec 7, 2004
    #4
  5. Gord

    Ty Ford Guest

    As I mentioned before; good tubes are better than bad solid state. Good solid
    state is better than bad tubes.

    Ty Ford



    -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
    stuff are at www.tyford.com
     
    Ty Ford, Dec 7, 2004
    #5
  6. Gord

    Pooh Bear Guest

    If you want to be pedantic, there *is* a tube sound, a bipolar transistor
    sound and a *fet* sound.

    This arises from their different 'transfer characteristics'. No gain
    device is linear. The non-linearities produce audible effects such as
    distortion. Tubes and fets produce mainly even order distortion products
    whereas bipolar transistors produce mainly odd-order distortion.

    There is one *big* caveat. A single bipolar transistor stage can provide
    much more gain than a tube ( or fet ) stage. This allows use of local
    negative feedback to reduce it's THD.

    Transistors are so much cheaper ( especially when within an IC ) that it's
    no problem to use lots of highly linearised transistor stages to produce
    vanishingly small amounts of distortion. This can be achieved through
    local and / or global feedback. In comparison, it isn't really practical
    to do this with tubes.

    Note that feedback isn't a bad thing like some audiophools ( who wouldn't
    understand technology if you whacked them round the head with it )
    suggest. Even valve ( oops tube ) circuits use feedback.

    For a mic pre-amp, a critical factor is the noise figure. Suitable bipolar
    transistors ( and some fets ) have such low noise figures that it's
    possible to directly ( a.c. ) couple the mic to the active devices and get
    super noise figures.

    By their nature, tubes do not perform so well with regard to voltage
    noise. To get a really quiet tube pre-amp you *have* to use an input
    transformer.

    Transformers have a whole stack of deficiencies of their own. This has to
    be considered in the context of a tube pre.

    Transistor mic pres don't need input transformers. Tube ones do. That
    alone is likely to colour any comparison.

    Choose one you like.


    Graham
     
    Pooh Bear, Dec 7, 2004
    #6
  7. Gord

    Ty Ford Guest

    and will someone please hand me a KleenWipe to remove the coffee from my
    screen.

    Ty


    -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
    stuff are at www.tyford.com
     
    Ty Ford, Dec 7, 2004
    #7
  8. Gord

    Mike Rivers Guest

    You've just been quoted (so people know what you said). There are
    people who say that they like the preamps that they make using tubes.
    There are people who say they like the preamps they make using solid
    state components. With only a few exceptions, there is someone who
    loves every preamp ever made. There are no generalizations other than
    "sounds good most of the time" or "sounds bad most of the time",
    neither of which apply to tube or solid state design.
    No. A well designed preamp is a well designed preamp. There are many
    preamps, both solid state and tube, that have basically good designs
    but certain compromises have been made to save money, to meet
    production schedules, or simply out of ignorance (for instance the
    importance of a well designed grounding system) and those are not as
    well designed as preamps where everything that can possibly be looked
    at AND LISTENED TO has been investigated and evaluated.

    The Gordon preamp made by Grant Carpenter is a good example. If you're
    ever at an AES show, stop by his booth, look at his preamp (he always
    has one with the cover off) and talk with him for a while. This is
    probably the most completely designed preamp I have ever seen (and
    it's solid state). Is it the best sounding preamp ever? I don't know.
    He thinks so, so do his customers. Will it replace all the API, Great
    River, Millenia Media, Manley, Neve . . . preamps out there? I doubt
    it - because they all sound different.
    Probably very little. It depends more on the mics you have and the
    techniques you use.

    --
    I'm really Mike Rivers ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
     
    Mike Rivers, Dec 7, 2004
    #8
  9. Gord

    Scott Dorsey Guest

    This is a horrible oversimplification, though. A pentode has a totally
    different transfer characteristic than a triode. A triode set up as a cathode
    follower has a totally different transfer characteristic than one set up
    for voltage gain. All of these tube circuits sound totally different... so
    how can we say there is a "tube sound."
    --scott
     
    Scott Dorsey, Dec 7, 2004
    #9
  10. Gord

    play-on Guest

    sweet ( P ) Pronunciation Key (swt)

    Pleasing to the senses; agreeable: the sweet song of the lark; a sweet
    face.

    Pleasing to the mind or feelings; gratifying: sweet revenge.
    Having a pleasing disposition; lovable: a sweet child.

    -----------------------------------------------------------------

    What adjectives to you prefer, since I have no lab to test these
    things in. The top end on the Forsell sounded more liquid somehow, a
    bit softer, the detail ever so slightly more blurred sounding. To me.

    Al
     
    play-on, Dec 7, 2004
    #10
  11. Gord

    Mike Rivers Guest

    Yeah, I know a mic preamp just like that. C'mon, that doesn't say
    anything about frequency response, distortion products, or stray
    noises.

    --
    I'm really Mike Rivers ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
     
    Mike Rivers, Dec 8, 2004
    #11
  12. Well, then, it seems pretty clear that - just to be contrary - someone here
    should go on record as *hating* every preamp ever made... who's it gonna be?
    Huh? C'mon, somebody step up to it!

    :D

    Neil Henderson
     
    Neil Henderson, Dec 8, 2004
    #12
  13. Gord

    annonn Guest

    Yes, ... but not at the same time.

    RD
     
    annonn, Dec 8, 2004
    #13
  14. Gord

    Pooh Bear Guest

    Is it horrible ?

    It's a simplification for sure but at least it gives the OP some ides of the
    factors involved which is what I thought he was enquiring about. I also avoided
    mentioning ICs much.
    Perfectly true. And of course all the tube nuts now seem to like to triode connect
    their pentodes it seems. Maybe it's flavour of the month ?
    For a mic amp most of the work is the voltage gain. I'm sure a cathode follower
    would be nice on the output but don't even get me started on the limitations of
    'single ended' followers. A sad limitation of tubes is the absence of the
    complementary pair.
    'Cos the market says so ? I have played iwth the idea of simulating a 'tube sound'
    just using a fet but I'm sure the tube fans want a real fire bottle.


    Graham
     
    Pooh Bear, Dec 8, 2004
    #14
  15. Not yet mentioned is a qualitative fundamental difference between
    junction transistors and field effect devices (both semiconductor
    and non-conductor-hot-cathode): BJT's have an intrinsic granularity
    caused by their integer number of injected electrons or holes.

    For some microphone level signals and typical beta's, this might
    become an audible issue. Field effect devices' granularity goes
    way down into the spooky-physics level.

    Not all that many years ago, some tree-hugging types were making
    a related argument for tape head amplifiers and phono cartridge
    amplifiers. Of course, nobody cares about those things anymore.

    Chris Hornbeck
    "Shi mian mai fu"
     
    Chris Hornbeck, Dec 8, 2004
    #15
  16. Gord

    Animix Guest

    I've got 7 Forssell channels here (a CS-1 and a JMP-6 prototype-I've also
    demo'ed the FEtcode and it's a wonderful sounding circuit too) I've also got
    a GR MP2-MH. I hate trying describe the sonic qualities of preamps, so
    please excuse the audio porn analogies I'll be making, but I did a shootout
    between the JMP and the GR a while back reamping a recorded source through a
    pair of ADS 1520's into a Stephen Paul U87 (3 micron) which was palced about
    7 feet in front of the ADS' speakers about 4' off the floor. The recorded
    source was *Forget About It* by Allison Krause. Lots of ear candy as far as
    well recorded and mixed acoustic instruments. I'd also describe the Forssell
    as *sweet/warm with a softer top end, (the JFet circuit I figure)* and the
    GR as *sweet/accurate with a bit more open top*, but both are in that same
    sonic big league. I've got a CD of that test around here somewhere.

    Doug Joyce
    http://www.graphicresultsofdurango.com/musicstudio.html
     
    Animix, Dec 8, 2004
    #16
  17. Gord

    play-on Guest

    My ears & brain are subjective, not lab measurement devices. Didn't
    hear any stray noises or distortion. So how else does one describe
    the differences one hears?

    Al
     
    play-on, Dec 8, 2004
    #17
  18. Gord

    play-on Guest

    Uh huh uh huh... you said the "s" word... sweet.

    Al
     
    play-on, Dec 8, 2004
    #18
  19. Gord

    DeserTBoB Guest

    FINALLY...someone got it RIGHT. "Tube sound," in most cases, is
    really "transformer sound." Get rid of the transformer coupling in a
    tube circuit and you have "FET sound."

    dB
     
    DeserTBoB, Dec 8, 2004
    #19
  20. Gord

    Pooh Bear Guest

    At the atomic level for sure !

    Have you recently checked the charge on an electron ?

    Quantum effects are present in all devices if you want to labour the
    point. Your point is largely spurious. The method of control of current
    is interestingly different but please don't labour the point.

    I suppose you'll be counting the *exact* number of electrons passing from
    cathode to plate next ? Ooops - that implies quantisation - i.e
    'granularity' too !

    LMAO !

    They were nuts.


    Graham
     
    Pooh Bear, Dec 8, 2004
    #20
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