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topology

Discussion in 'Pro Audio Equipment' started by andshesbuyingastairway, Apr 21, 2007.

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  1. does anyone know if the PCM units like lexicon 70, h3000, yamaha spx-90, and mytek 8X192 use hybrid IC coupled with op-amps?

    and could anyone please verify if the el-8 distressor uses a hybrid IC with the individual semiconductor being op-amps as well? and if it is coupled with PCM technology would that define this particular piece as linear or non-linear?

    i know that most of the others like lexicon, eventide, and mytek are defined as linear, so does that mean there is no use of centralized semiconductors and they are not hybrid IC?
     
  2. dementedchord

    dementedchord Well-Known Member

    i'm having a bit of a problem decifering your post... i think you may be mixing ideas that may be unrelated... so lets start by saying that it's not unusuall for companies to have custom made chips... especially as the "brain" of the unit... sometimes it's as simple as an ASIC cpu.. application specific.... you see there's no need to use a P(2-4) intel chip for instance if all it's going to do is create reverb... that is often then coupled with more "generic"(even if high end) converters or opamps... this would have nothing to do with "linearity"or whether they use PCM... dont know if thats what you wanted or not...
     
  3. RemyRAD

    RemyRAD Well-Known Member

    The definition linear and nonlinear, have multiple meanings in many different forms of electronics, function and processes, especially when referring to audio and video.

    For instance, analog tape recorders utilize a thin piece of linear tape, generally made from mylar polyester film and coated with iron oxides. However, the process of analog recording produces nonlinearities in the signal, on the tape, depended upon recording level and internal electronics adjustments. These nonlinearities from analog tape is part of its magic. The same results are not obtainable in the digital realm since digital recording is a linear process that must be free of all nonlinearities.

    Audio power amplifiers are linear in nature and become nonlinear when their operational specifications are exceeded, i.e. distorted.

    Nonlinear editing generally applies to a contiguous full recording, that can be manipulated after-the-fact, without harm or destruction to the original track/file by having the ability to composite and/or manipulate pieces of the performance, editing it in a nonlinear fashion, where the computer has the ability to jump around from place to place in a nonlinear fashion.

    Most operational amplifiers, be they discrete transistor circuits or integrated circuits and even tubes, are generally used for audio purposes within their linear field of operation capabilities. If they are outside of their linear input to amplification output ratio, the amplifier is said to be unlinear, which is generally something that's not good for audio and should not be confused with nonlinear.

    Linear decreasing concentric circles
    Ms. Remy Ann David
     
  4. dementedchord

    dementedchord Well-Known Member

    oh... so now you surface....
     
  5. bwmac

    bwmac Active Member

    Stock her post

    LOL, I just follow Reme so that I can benefit from her free lessons, LOL.

    And I'm sure I'm not the only one that benefits from her post.
     
  6. digital pulse modulation (PCM or sigma-delta) is not necessarily always linear, which is why i asked in the first place. LPCM is usually interchangable with PCM and thus typically linear, but not always. if the IC chips contain any form of analog op-amp (discrete or integrated) in the pcm70, then it makes much more sense that this system is going to exhibit non-linear behavior (for which i draw a comparison to the distressor, which as we all know DC couples the PCM digital IC microprocessor with discrete/integrated analog IC) does the pcm70, h3000 do the same? doubtful considering how much older of a technology it is.


    you are confusing non-linearity with non-destructive editing in your fourth paragraph. and you also seem to be equating IC with op-amp. in the audio world what op-amp based topology doesn't utilize discrete circuitry? are you insinuating that the pcm70 and h3000 use the integrated op-amp as analog IC?

    analog pulse modulation processes like PWM, PPM, PAM, PDM may (try to) exhibit linear behavior through the method of their quantization. in fact PCM and delta sigma are by all technicality not true modulation. in any case, there are going to be more non-linearities in hybrid (discrete) IC than monolithic (integrated) IC, even within the analog IC realm.

    either way, maybe i should rephrase my question. you have a pcm70 right remy? or something like it i'm sure. are there individualized op-amps inside it? or is it monolithic? or maybe more generally; does it use a digital IC or an analog IC?

    in the case of the mytek i believe the semiconductor is the crystal oscillator being used for the internal studio clock. is this a mixed-signal IC?

    in digital microprocessors, transistors act completely differently. just as analog devices are designed to be linear, they still contain nonlinearity so is the case with digital.
     
  7. dementedchord

    dementedchord Well-Known Member

    is that you liquidstudios????
     
  8. moonbaby

    moonbaby Mmmmmm Well-Known Member

    BINGO!!!
    BTW, the Distressor is an analog signal processor. The "digital" is ONLY the presets on the control side, like an RNC.
     
  9. can you describe exactly what makes the EL-8 have part digital in it? i was under the assumption that for something to be "digital" it uses PCM (at least in the case of audio pulse modulation, excluding delta-sigma) so it uses a monolithic chip for that digital section, in addition to that you can switch between the discrete/integrated op-amp analog IC's...

    does the integrated op-amp IC constitute the digital section, or at least part of it? that's an analog IC...please elaborate
     
  10. dementedchord

    dementedchord Well-Known Member

    what he was descfibing is i believe "digital recall"of analog parameters...


    "integrated op-amp IC constitute the digital section"
    is an oxymoron...
     
  11. RemyRAD

    RemyRAD Well-Known Member

    Like Army intelligence!

    While my answers may not be totally, technically correct, (I don't have a degree in electrical engineering), I'm trying my best to describe and/or answer confusing technical questions from technically clueless oriented audio questions that have no bearing on audio in itself. So, while monolithic integrated circuit chips can be cooked up as audio operational amplifiers, not all operational amplifiers, or "Op-Amps", have to be monolithic integrated analog circuit chips. An operational amplifier, can be made from tubes, transistors and integrated circuit chips and is after all, an amplifier. Like the API's and Neve's, their Op-Amps were made from discreet, transistor, resistor, capacitor circuits, on little 1 inch square circuit boards, some potted in epoxy and others not potted. No integrated circuit chips involved there. My old Crown DC 300 A speaker power amplifier is really a large, hybrid, integrated circuit chip and discrete transistor DC Operational Amplifier on the order of 150 W per channel of current capability. The old Lexicon devices, like my PCM 60 & 70 & LXP1's, used a combination of, mostly monolithic integrated circuit chips of the 1970s and 80's variety. Some were off-the-shelf integrated circuit operational amplifiers, like the Texas Instruments LM741/709's & others, National Semiconductor's of numerous model numbers, Signetics 5534's & 5532's and others, used for inputs to the analog to digital converters within and in the output circuits as well. Whereas their reverb algorithms and effects were contained in custom digital integrated circuit chips and/or PROMS & EPROMS, which were then sent back to the digital to analog converter chips and/or discrete components, which was then fed to the output operational amplifier drivers, which utilize both monolithic integrated analog circuit chips, in combination with discrete power transistor output buffer amplifiers and other similar combinations of integrated circuit chip only, discrete parts only and combinations thereof. As you seem to be somewhat informed, electronically, some integrated circuit chips are strictly analog, some are strictly digital, others might offer hybrid circuitry within a monolithic integrated circuit chip, of both analog and digital elements. It's all in how you grow them and cook them in the oven! Have you ever looked through a semiconductor manufacturers catalog?? There are thousands of combinations that can be utilized of transistors and integrated circuit chips. No single combination is really any better than the other. It's all in what you want to hear, that's where real engineering begins. You have to become familiar enough with the equipment available to know or have any understanding of what you want your product to be in the end. While a thorough technical knowledge of actual circuitry and theory is desirable for the circuit designer, it certainly isn't necessary for a recording engineer to know completely what makes it tick. It's only handy to know the basics and what your limitations of the equipment might be. If you want to design a circuit, go to school or just start to do it. Crystal clarity and other blah blah marketing hype is just that.

    We don't all want Crystal Clarity but you might want to See-Alice?
    Ms. Remy Ann David
     
  12. demented: maybe i could have worded it better, but it could be construed as feesible when considering a mixed signal integrated chip. besides you didn't quote me right.

    remy: first i want to say thank you for trying to tackle my questions with me, i appreciate this. anyways, i never said op-amps had to be monolithic but a discrete IC system is virtually the same thing as a hybrid IC system. so in those API's and neve there would have been IC involved. an IC is just a chip. in a lot of the newer tube and transistor gear there is the hybrid IC still, with stuff bonded to the PCB. i don't know if an op-amp technically is classified as a semiconductor but i would assume it could be. correct me if i am wrong on that assumption.

    so onto the lexicon thing, so you are saying the old one's for an "input" stage use monolithic analog op-amp IC, for the containment of effects use the digital IC, and for "output" use which specifically? one, the other, or combo? for the pcm70 per se.

    also for the newer lexicon model like pcm90, would the topology line from input to ouput be similar to this?

    do you happen to know if the mytek converters or some of the new converters use mixed-signal IC? or since it uses a crystal semiconductor would that classify it as some other form of IC? why do you think crystal clarity is hype when it dramatically helps to keep your internal studio clock in better sync? anyways thanks again remy, i really appreciate it

    however i am sorry to disagree, but i do believe these "technically oriented" topics do have a significant bearing on the audio itself.
     
  13. AudioGaff

    AudioGaff Well-Known Member

    For what it is worth, Most audio devices including reverbs such as the PCM70 and H3000 use opamps of some kind. The PCM70 like many digital effects units and all of the Lexicon reverbs, are based around a custom audio ASIC chip(s) that are optimized for their custom DSP alg. they run.

    The H3000, like all the modern Eventide versions, is different in that it uses a more off the shelf audio processor/controller chip and a custom OS with dozens of high level compiled DSP modules that when combined and then real time compiled, form a custom alg.
     
  14. granted, but you might want to ask someone like john hardy how much better it is to use a discrete op-amp versus monolithic. just because it uses an 'ASIC' doesn't necessarily tell me whether or not its digital or analog or whether or not its discrete/monolithic/mixed-signal. so you can see it doesn't tell me much about the sonic nature involved.
     
  15. AudioGaff

    AudioGaff Well-Known Member

    There were very few audio products made in the 1980's that had true mixed signal capability as it is known and commonly used today. If it used an ASIC or custom alg, then it would be considerd a digital audio product.

    Discrete/monolithic as you seem to use the terms, would not be something that would be considered normal in a digital effects unit made back in yester-year or today. A little effor and research on your part including mabe getting your hands on one or more the products you speak of, would go a long way in answering your own questions and get further along than just shot-gun guessing?
     
  16. the point is that ASIC is an extremely broad term, don't know why you are trying to argue that when all i am trying to do is seek a path towards enlightenment through recording.org. thanks for reducing my posts and overall knowledge to 'shot-gun guesses.'

    you're right mixed-signal wasn't predominant in the 80's because A/D itself hadn't progressed substantially, but one of my topics of discussion was the mytek converters.

    and no as we are seeing in this topic just because something uses (even digital) ASIC does not mean it's digital audio. in fact did moonbaby not (somewhat appropriately) consider the EL-8 analog. despite the fact that the pcm 70 uses a digital ASIC PCM in the mix, i have a hard time characterizing it as digital even though PCM is digital. it's both digital and analog (something i previously referred to as 'digital modeling' whether that's right or wrong), which is why the intricacies of this discussion can not be summed up with merely ASIC.

    how would discrete/monolithic properties not apply to digital effects made any day? most of the IC chips we are talking about were designed in the 60's. i don't get where you are going with this, so i'm just going to wait to hear back from remy given that she has been slightly more helpful thus far and has just verified that indeed discrete/monolithic "as i seem to coin the terms" are used differentially in the products of any day

    p.s. i have a distressor (and that's one...) so please stop trying to judge me and let's enhance this discussion if it should prove beneficial to the topic.
     
  17. AudioGaff

    AudioGaff Well-Known Member

    With due respect to Remy, I am certainly am no sloutch with having 20+ years of semiconductor experience. But I don't get into it that much around here as there are better places where such things are discussed in detail.

    In any case, if you can't understand that a device such as a digital reverb processor like the PCM70 that uses an ASIC is considered a digital device and that the EL-8 is a pure analog device with some digital control, then you'll have to go back a few steps and re-review some basics before you can go forward.
     
  18. audiogaff, give me an example of a place where things are discussed in such detail in the form of a hyperlink.

    what's the difference between the topolgy involved with the pcm70 and el-8? both have very similar circuitry integrated sections, pcm digital sections, and discrete sections...
     
  19. AudioGaff

    AudioGaff Well-Known Member

    Your kind of funny. I'm glad your able to laugh at yourself. Ya, like I'm going to be the one dumb enough or cruel enough to pass a troll like you on to any hi-tech forums where highly educated mature engineers discuss audio, DSP or ASIC technology.
     
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