Amp Latency?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by blacktip, Feb 2, 2015.

  1. blacktip

    blacktip Supporting Member

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    Do you think the complexity of an amps circuit could cause a perceived delay from a note played on your guitar to when you hear it through your cab? I had a Mesa 5:50 that I always felt I was playing ahead of what I was hearing. I'd be interested in your thoughts about this. I'm considering the MarkV 25
    that I can't check out first. I'm thinking it might seem similar in that respect.:huh
     
  2. Blix

    Blix Supporting Member

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    Nope, no such thing as latency in an analog amp.
     
  3. RocksOff

    RocksOff Member

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    Well, there is. You can't measure it, though. Ha! Those little fellows are traveling at the speed of light!
     
  4. Blix

    Blix Supporting Member

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    Yeah, you definitely have to put a couple thousand miles of cable in an amp to detect any. :)
     
  5. blacktip

    blacktip Supporting Member

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    Well.. It's an odd thing then because over the years I've had a dozen or so amps in the same room with the same minimal effects & speakers etc and that was the only amp that seemed like that. So anyway I'll take that as good news an order the mini markV and hope for the best. Thx
     
  6. filtersweep

    filtersweep Member

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    Could it be the room reflection, or something involving the reverb--- or do you have some wonky digital gear in the signal path?

    I have a modeler for practice that I 'feel' has some latency, but it could all be in my head.
     
  7. denitronik

    denitronik Member

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    Electron travelling latency: very little but acoustic latency yes.
    Don't forget that you get roughly 1 millisecond of delay per 10 feet of distance from your amp.
     
  8. xtian

    xtian Member

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    I can imagine how an amp with significant sag might be perceived as delay. But I don't guess the Mesa would have much sag.
     
  9. teemuk

    teemuk Member

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    Are you using the feedback loop? Is it one of those Mesa's parallel atrocities...?
     
  10. pdf64

    pdf64 Member

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    In this case perhaps not sag but (given suitable guitar and amp control settings) bias shift / blocking distortion might take the attack out of the signal envelope.
     
  11. TimmyP

    TimmyP Member

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    I read about a company giving an old blues guy a SS amp to play on a show, and he complained that "the notes are comin' out too fast". So they put a delay on it, and when they got to 10ms he said "that's it!". Makes no sense :)
     
  12. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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  13. tschrama

    tschrama Member

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    BS.

    Groupdelay...
     
  14. J M Fahey

    J M Fahey Member

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    C'mon guys, don't fight :)

    You're both right :)

    "Group delay" is what you get when you cascade a few gain stages with poor "slew rate " :)

    That said, I think pdf64 is quite close, remember typical grids become forward biased diodes as soon as grid comes more positive than cathode, which in a typical 12AX7 mans peaks above 1.5 or 2V will:

    a) usually get clipped , or at least strongly attenuated, since previous plate can provide at most 1 or 2 mA into a now low impedance load.

    2) coupling cap gets negatively charged and shifts bias ... driving tube towards cutoff and lowering gain.

    3) so you have a crude compressor which over vreacts to an incoming peak ... causing a crude "attack delay" effect.

    That "extra 10ms added" sounds reasonable.

    4) that does not happen in an Op Amp , so any modern SS pre stage will, by comparison, sound "faster" than a tube one.

    5) Death Metal guys know that and prefer SS amps .
    Smooth/spongy/"organic" Blues players prefer the opposite.
     
  15. Tone_Terrific

    Tone_Terrific Member

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    I've heard or felt that less than snappy response.
    From old SS amps, in the '70s, and from digi processors.
    I know digi latency is real, measurable, and doesn't bother me up to a certain point, not sure where that point is though.
    The distant feel from some old ss rigs remains a mystery. I don't recall any problem with tube amps. I am NOT talking sag or OD response.
    Maybe it was that polarity thing that pops up here from time to time.
    Sure can't go back to reverse the speakers, now.
    OP you should check it out.
     
  16. GT100

    GT100 Member

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    That's not entirely true.
    The electrons inside the tube are going crazy fast but not at the speed of light.
    No way.

    Lloyd


    Sent from my iPad using Tapatalk
     
  17. blacktip

    blacktip Supporting Member

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    I was curious about their "Dyna-Watt" technology. Member teemuk explained "the tubes for a brief moment dissipate excessive power, which is quickly brought down by the power supply sag characteristics: After the burst of power peak the screen voltage sags quickly limiting dissipation to safer values". He went on to say that peak would most likely be very harmonically distorted among other things. On the surface it would seem Dyna-Watt would make an amp seem "faster" more immediate, then again maybe not. I'm kinda above my pay grade on this but maybe this would contribute to what JM Fahey had posted. Anyway thanks for all the replies.
     
  18. CubanB

    CubanB Member

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    It's modellers where latency comes from IMO (us talking about it). At first it was quite noticeable in the early days but over the years they've improved it a bit. I'm sure even the best have a little, it's just that it's hardly noticeable these days with good ones.

    With anything there's latency, even just for the time it takes from the sound to travel from the speaker to your ears. But never heard or felt it in a proper tube/analogue amp. If there is any, it seems to be so small it's not noticeable.
     
  19. walterw

    walterw Gold Supporting Member

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    it's at least at a large percentage of the speed of light, like more than half.

    way fast enough for any and all analog sound equipment to be "zero latency" to us humans, at least until it hits the speakers and the air.
     
  20. RocksOff

    RocksOff Member

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    Hold on a sec. Light travels at C in a vacuum. The electromagnetic wave moves the same speed because of the vacuum, right?

    I suppose I should clarify. While the individual electrons are not travelling at the speed of light, the electromagnetic wave which moves them does... with electrons arriving at the potential seemingly instantaneously.

    I think.
     

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