Herb Reichert's tube manifesto

Discussion in 'General Audio Discussion' started by rlow, Jun 28, 2018.

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  1. rlow

    rlow A happy woofer

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    Over on AudioStream, for those who haven't read it yet, I thought it was an interesting read:

    https://www.audiostream.com/content/problem-tubes

    Here's a few interesting excerpts:

    I know this is mainly focused on speakers rather than headphones, but curious what folks on here think of some of these assertions. Is it all nonsense?

    Many people on here seem to consider tubes to add "coloration" to the sound. This doesn't appear to align with HR's feelings.
     
    Last edited: Jun 28, 2018
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  2. Taverius

    Taverius Smells like sausages

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    But the coloration differs by tube (both type of tube and model), and caps have a massive effect, as well as trasformers and everything else.

    The ec studio sound very very different from a feliks else, studio neutral vs ultimate warmpoo battle royale champion.

    I do find they have a characteristic presentation, though that might be due to me basically only ever listening to SETs and the mjo2 I used to have.
     
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  3. ultrabike

    ultrabike Measurbator - Admin

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    I don't agree with Herb.
     
  4. k4rstar

    k4rstar Done his time

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    Here's what the late Charles Hanson of Ayre had to say about Herb:
    I am inclined to agree with Charles. I think when used as an amplification device the triode has greater net fidelity than the transistor, but Mr. Reichert would not be my first choice to champion such a cause. Also, everything has a sound.
     
  5. ultrabike

    ultrabike Measurbator - Admin

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    All right I'll say it out loud. Herb is full of shit.
    1. Feedback is not a "newer" technology. It's been around for a long fucking time.
    2. The vacuum tube amplifier reveals a secret of the universe in its operation." Seriously WTF!
    3. "The reason JA says, “Underdamped low frequencies; and heavy on the second-harmonic sauce” is because designers of tube amps are less inclined to sabotage the musical potential of glass and fire with textbook amounts (20-50dB) of feedback or degeneration" Inclined? Fuck that. Most tube devices lack the gain that many solid state devices have which is the backbone of effective feedback error correction.
    Again, Herb is full of shit. Likely a "high end audio" tool. Don't read his bullocks.
     
    Last edited: Jun 28, 2018
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  6. rlow

    rlow A happy woofer

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    I think he was saying they don't have a specific sound signature (a "characteristic sound") that can be attributed to all tubes (e.g. they're all "warm").

    At least I would certainly hope that's what he meant, or he's deaf.
     
  7. ultrabike

    ultrabike Measurbator - Admin

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    He is making a "subjective" case against feedback and solid state devices.

    Herb is probably deaf.
     
  8. frenchbat

    frenchbat Almost "Made"

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    Intellectual deafness is a thing. In the case of ol'timers like this, it's usually that they stopped caring and experiencing with varying techs and gear, so they just make blanket statements based on technology from 2 or 3 decades ago.
     
  9. maverickronin

    maverickronin Friend

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    Tubes don't have to have those kinds of colorations but given the number of tube amps which sound like the entire mix was run though the through the guitarist's effect pedal chain it's easy to see where the notion comes from...
     
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  10. ultrabike

    ultrabike Measurbator - Admin

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    Herb used to hang with Steve G. Not good.

    When Coke met Weed

    [​IMG]
     
    Last edited: Jun 28, 2018
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  11. ultrabike

    ultrabike Measurbator - Admin

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    All BS aside. Yes. Herb's article makes no sense to me. It's got a lot of distortion.
     
  12. rlow

    rlow A happy woofer

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    Lol. Can we label this picture "When Coke met Weed"?
     
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  13. 13713

    13713 Rando

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    I read this article yesterday. I waited and mulled on it for a bit and I reread it today. I have come to the conclusion that I am not the target audience for most audio articles.
     
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  14. Johnny2Bad

    Johnny2Bad Rando

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    I've never found vacuum tube amps or preamps to sound "coloured", at least not examples I would consider worthy of a HiFi system. I have heard some el-cheapo Chinese devices that were, but similarly priced Solid State stuff sounds that way to me as well.

    As for "warm", if that means the opposite of "cold", maybe. But you could add SS ONKYO, Luxman, McIntosh and Threshold in that same boat. Or most Class A SS amps, period.

    I remember when Sonic Frontiers first released their pre's and power amps in the 1990s people complained that they were "too clean" and they couldn't tell they were tube amps, like they expected tubby bass or something. And it's a rare recording indeed that hasn't passed through a small-signal tube somewhere (and I'm not referring to guitar amps). A bit off-topic, but there is a similar argument with regard to transformers, which can sound coloured if not properly impedance-matched, but also are pretty much guaranteed to have been used somewhere in the recording chain.

    Herb takes a few liberties in his explanations, so in a few cases they are as much stereotypes as "tube sound" is. But he does make some good points (linearity, for example, which isn't subject to opinion, as it's a simple fact).

    Vacuum State does sound different than Solid State to me, (I find tube amps particularly adept at conveying a soundstage) but I've heard excellent examples of both. I think part of the reason is they require so much fewer components in the signal path than typical SS designs do, and that seems to matter when conveying certain attributes of music. But not all attributes ...

    About the only really different thing between them is the power delivery, where you need to insure your SS amp has ample continuous power capacity to handle every level with the speakers you choose, while a Vacuum State amp can generally produce large amounts of instantaneous power above it's continuous rating. But those are not "quality" issues, they are system configuration issues.

    I'd have to dig it up, but somewhere in Stereophile they explored that power issue and found Vacuum State amps could often deliver 3- and 4x their rated continuous power for brief transients without exceeding their distortion ratings, while SS generally could muster less (closer to 2x, and a few that were less). (The 300B seemed particularly adept at it).

    Still, that's just a reflection of the technology, not the sonics per se. That is consistent with my experience, where a 100w SS and a 40w Vacuum State seem to me to be equally powerful in a room with loudspeakers.

    As always, what we desire is best achieved via a "system". No one component stands alone, everything must be configured to work together. Achieving that is more difficult than some believe. I find it unfortunate that so many people, especially now with easy internet purchasing options, feel they can build a HiFi out of a catalog. Doesn't work, or at least doesn't work if you want the best sound quality for your investment.

    Where the choice of tube or SS amp comes into play is the amplifier-loudspeaker (or -headphone) pairing is the most critical.
     
    Last edited: Jul 7, 2018
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  15. Dzerh

    Dzerh Friend

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    question to specialists - ignoring overdrive, can better linearity be just a matter of scalability coming from lower gain and higher operation voltage? Or it is inherited with the medium - vacuum vs semiconductor?
     
  16. sodacose

    sodacose MOT: WTFAmps

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    Generalizations are difficult to make, but you can look at the theoretical mechanisms of operation for some interesting nuggets.

    In a tube, current is transferred between anode and cathode by the space charge in a vacuum. Child's Law states that current in a vacuum is directly proportional to anode voltage (to three halves power) and inversely proportional to the distance between electrodes (squared). The speed of electrons depends solely on the applied voltage.

    In transistors constructed of doped sandwiches of semiconductor material, Child's Law doesn't apply. Here we use the Mott-Gurney law. This states that the current density in a semiconductor is directly proportional to anode voltage (squared) and inversely proportional to the thickness of said material (cubed). The speed of the electrons depends on both the electron mobility of the semiconductor (assumed to be constant) and the applied voltage.

    There are extra constants for calculations in either case, but notice the similarities. In both cases, we can assume distance between electrodes (whether separated by a semiconductor or a vacuum) doesn't change. The difference here is the power for the voltage term. The generalization is that current density through a vacuum is less affected by changes in anode voltage than is current through a semiconductor.

    That is to say, the theoretical mechanisms of current transfer through a vacuum is more linear than that through a semiconductor. In reality, geometry, application, and other factors matter, aside from just materials. Some tubes are more linear than others just as some transistors are more linear than others. There are bad ways to bias and operate tubes just as there are good ways to bias and operate transistors.
     
    Last edited: Jul 19, 2018
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  17. Dzerh

    Dzerh Friend

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    Thank you.
    From your explanation I'd speculate that electron mobility being not exactly constant (or more volatile than in vacuum) may be the main reason for inherently worse linearity of transistors. If such thing indeed exists.
    - meaning more relaxed requirements to the power supply for tubes?
     
  18. sodacose

    sodacose MOT: WTFAmps

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    To be clear, I am also speculating on how the medium is affecting linearity. I'd definitely agree though that if electron mobility is not constant, it would be a culprit in any non-linearity. This is where theory and reality part ways, I think.

    I was thinking more in terms of AC behavior with signal.
     
  19. ultrabike

    ultrabike Measurbator - Admin

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    Herby was probably on an acid trip when he wrote his article.

    AFAIK, many modern power "SS" amplifiers are capable of delivering more continuous power than many vacuum tube designs. In fact, I've seen a lot of recommendations steering folks to use efficient speakers when using vacuum tube based products.

    Maybe you are referring to the old "hard" vs "soft" clipping which result in different harmonic distortion issues? It is my experience that both "hard" and "soft" clipping result in shit sound.

    All techno-babble aside, I agree that proper pairing of a system should yield fantastic results with either "SS" or "vacuum tube" designs.

    Does Child's and Mott Gurney's Laws provide any insights as to why certain "SS" designs offer lower distortion (i.e. more linearity) and lower noise (using AC signals such a 1 kHz tone) than certain "high-end" vacuum tube designs?
     
    Last edited: Jul 19, 2018
  20. sodacose

    sodacose MOT: WTFAmps

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    You'd have to be more explicit about the certain designs in question, but to continue digging the dangerous pit of generalizations...

    Topology has at least as much to do with it as the device used, though solid state has one advantage in that respect: it's available in a p-channel as well as an n-channel. If designing for high open loop gain, direct coupled, and large amounts of feedback (which will measure well), this is a significant leg up over tubes.

    Not to say tubes cannot be used in that type of application (just not quite as easy). For example, the Williamson amp is the granddaddy for this kind of design approach to linear audio and was published back in the 40s. I'd say rather than devices, it's more interesting to consider things as schools of design thought: high feedback multi-stage amplification vs low/no feedback minimalist design.

    It just so happens that the stereotypical transistor amp is Class AB differential with lots of feedback and the stereotypical tube amp is Class A single-ended without global feedback. Doesn't mean it must be so. Guys like Pass love bucking that trend.
     
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