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Class D: Analog or Digital? How to tell?

Discussion in 'Amps and Cabs [BG]' started by CPplaysBASS, Mar 3, 2015.


  1. CPplaysBASS

    CPplaysBASS

    Mar 17, 2007
    Ontario
    Ok, I did my best to find an existing thread on this but only found conflicting information that skirted around my key question, which is ...

    If you are considering a Class-D amp, is there a relatively easy way to determine if it's also digital or analog?

    The manufacturers of many lightweight amps seem to be vague in describing their own amps. The fact that too many people assume that all Class-D amps are digital doesnt help.

    What I have read and think I understand is the difference between an analog Class-D amp and a digital Class-D is simply the pre-amp controls and the signal being fed to the power stage? The power stage, in general terms, is the same and needs to be analog for speaker output - similar but more efficient than other classes? Close enough? I'm honestly trying!

    Either way, if the manufacturer doesn't come right out and say it in the manual but provides a schematic, is there a simple component (a chip, integrated circuit, etc) or lack thereof that definitively indicates whether the amp is analog or digital?

    I have the Traynor SB500H which I love and swear by regardless, but curious. If i email Traynor tomorrow, they will tell me about the SB500H specifically. I'm also interested to know in a more general sense. Hard to know what's what out there with so much misinformation. I sincerely hope this thread doesn't add to even more misinformation :)

    Cheers!
     
    Last edited: Mar 3, 2015
  2. George Mann

    George Mann Banned

    May 27, 2012
    Colorado
    The Class-D designation stands for an amp with a switching power supply regardless of the amp modules class or topology!
     
    Thumper19605 likes this.
  3. B-string

    B-string Supporting Member

    Not correct, class D is an analog output topology that uses PWM (Pulse Width Modulation). D was the next available letter and could be driven by a line frequency power supply (if desired) as well as by a SMPS.

    If the amp head includes DSP, then it has a digital conversion for effects which is then converted back to analog before it can be sent to a class D module.
     
    Last edited: Mar 4, 2015
  4. CPplaysBASS

    CPplaysBASS

    Mar 17, 2007
    Ontario
    Thanks guys. Appreciate it.

    Let me rephrase ... I know D is not digital. That's my point. That often the terms Class-D and digital are used interchangeably which is incorrect. Got it

    So what is it that makes an amp digital? Literally a circuit board or something in the preamp?

    If I have a micro head, it's not correct to assume it's also digital, correct? If so, how does a buyer of a micro head know if its digital if the manufacturer simply doesn't come out and say so?

    Unfortunately I need this dumbed down as simply as an amp with x is digital, an amp without x is not digital.
     
  5. seamonkey

    seamonkey

    Aug 6, 2004
    Class-d refers to the power amplifier section of the amp. Class-d is all analog all the time.
    http://www.hypex.nl/docs/papers/AES120_353BP.pdf
    Class-d was invented in the 1930's well before the digital age.

    Misinformation is thinking what's inside the box is tainted if it's digital.

    I have high confidence Traynor will give you honest information if you ask them. I would be amazed for an amp that size and weight not to be class-d, but if it sounds the same and has the same or better features, reliability, and sound of class-ab, I wouldn't care.
     
    Coolhandjjl and blindrabbit like this.
  6. B-string

    B-string Supporting Member

    The trouble is ad copy may say "digital" when none exists. If the amp has no built-in programmable effects it won't have any "digital" to it. Your signal is analog, it would have to digitized (analog to digital converter) then do what with it? Data is data, you can manipulate the data (effects) but numbers are numbers and can't be made "louder" numbers (amplified). The numbers (data) then go through a digital to analog converter to be amplified (analog). So if you have no onboard effects the amp is all analog.
     
  7. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Just curious, are you trying to avoid one or the other for whatever reason?
     
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  8. CPplaysBASS

    CPplaysBASS

    Mar 17, 2007
    Ontario
    The Traynor amp is Class-D. No question.

    If it's digital, that's fine. I use it, love it.

    I simply want to know what makes any digital amp digital ... let's leave Class-D out of it entirely. Sorry I even brought that into it.
     
  9. George Mann

    George Mann Banned

    May 27, 2012
    Colorado
    This designation class refers only to vacuum tube topology.
     
  10. B-string

    B-string Supporting Member

    Last edited by a moderator: Mar 9, 2015
  11. CPplaysBASS

    CPplaysBASS

    Mar 17, 2007
    Ontario
    No reason other than wanting to know if all micro amps are digital. If they are, it's not because of the power supply. So it's the preamp? All micro heads are digital? If not, as a buyer, what's the harm in knowing?
     
  12. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    A analog to digital converter, or digital switching of any kind, which could arguably just be some types of logic or timing switching for a relay. As Jon says, just comes down to ad-speak mostly though. And just having some digital elements doesn't necessarily make calling an amp "digital" all that meaningful or useful, IMHO.
     
    blindrabbit, CPplaysBASS and B-string like this.
  13. B-string

    B-string Supporting Member

    Vacuum tubes are not a typology, they are a device.
     
    Coolhandjjl likes this.
  14. B-string

    B-string Supporting Member

    MarkBass has amps that are included in the "micro" class and were SMPS with class A/B output (not class D).
     
    blindrabbit and CPplaysBASS like this.
  15. seamonkey

    seamonkey

    Aug 6, 2004
    Class-d started with vacuum tube technology. It wasn't practical until good SS devices came along.
     
    Coolhandjjl likes this.
  16. seamonkey

    seamonkey

    Aug 6, 2004
    TC is a good example of a digital pre-amp. They usually do a lot more, have presets, effects, and other automation.
    One advantage these kinds of pre-amps can have is they can feed a digital signal to recording of FOH. Once it's in the digital domain, keep it in the digital domain, up until you need to hear it, then it has to go analog.
     
    Coolhandjjl and CPplaysBASS like this.
  17. CPplaysBASS

    CPplaysBASS

    Mar 17, 2007
    Ontario
    Thanks Seamonkey and to everyone else. I'm getting a better understanding and will keep reading up on it.
     
  18. CPplaysBASS

    CPplaysBASS

    Mar 17, 2007
    Ontario
    God bless B-string!! That's something I can understand :) Muchly appreciated.

    I almost missed your post and glad i scrolled back. That answers my question precisely.
     
    S-Bigbottom, blindrabbit and B-string like this.
  19. B-string

    B-string Supporting Member

    My original education is almost as old and took some study to understand. PWM (as class D) was touched on for industrial controls at that time and nowhere near as complex as it is for audio use.
     
    Last edited by a moderator: Mar 9, 2015
    Bob Lee (QSC) and SirMjac28 like this.