Seriously: what is an analogue delay?

Discussion in 'Effects, Pedals, Strings & Things' started by solitaire, Mar 2, 2012.

  1. solitaire

    solitaire Senior Member

    Messages:
    3,721
    Joined:
    Jan 31, 2006
    Location:
    In the heartland of Sweden
    I mean the sound has to be recorded or stored somewhere. So is an analogue delay a digital delay w. some kind of lo-fi analogue circuitry or what is going on in there?
     
  2. Shiny_Beast

    Shiny_Beast Member

    Messages:
    7,995
    Joined:
    Apr 27, 2009
    Location:
    Ottawa Canada
    It's recorded in a few thousand tiny cpacitors built into the chips, something like that. I think in the purist sense it's a digital concept, but there's no specific conversion into a digital standard, run through digital processing, convert back to analogue sound etc...
     
    Marikian and Jack DeVille like this.
  3. Madsen

    Madsen Member

    Messages:
    6,344
    Joined:
    Aug 10, 2009
    Location:
    Southern California
    adolan and moore_for_less like this.
  4. johnnylighton

    johnnylighton Member

    Messages:
    519
    Joined:
    Feb 13, 2009
    Location:
    So Cal
    Is it easy to hear the difference between an analog and a digital delay?
     
  5. Akira Flux

    Akira Flux Member

    Messages:
    48
    Joined:
    Nov 18, 2011
    With a digital delay the repeats will be exact and clean (unless, like with the Strymon boxes among others, the digital algorithm is specifically designed to recreate analog effects and sounds).

    With analog they suffer a natural decay of clarity and loss of brightness.

    They sound very different (albeit both being delays).
     
  6. chervokas

    chervokas Member

    Messages:
    6,864
    Joined:
    Feb 16, 2008
    Usually, yes. Of course there are very different individual delays of each type, but typically with a BBD chip based analog delay (vs., say a tape delay which is, of course, an analog delay) the repeats are darker than the dry signal and degrade substantially with each subsequent repeat -- they get darker and darker and start to break up. Old school BBD analog delays typically also couldn't do long delays, often tapping out at around 300 ms. And many of the earlier stomp box ones had low headroom and kind of a low fi sound.

    With a digital delay the repeats are as crisp and clear as the dry signal and don't decay. Nowadays many maker of digital delays use circuitry to emulate the darkening and breaking up of an analog repeat.

    Most common today are hybrid delays that keep the dry signal analog but generate the repeats digitally voicing the repeat output to be analog-like. Something like the Wampler Faux Analog Echo is, to me, like having the best of both worlds.
     
  7. Waxhead

    Waxhead Member

    Messages:
    5,557
    Joined:
    Sep 9, 2007
    Location:
    Surfin at Merewether Point, NSW Australia
    hehehe that's the whole point - No - there's only a slight difference between the 2 imo.

    You have to have very good ears to spot any and punters hehehe - have got nooooo chance.
    THey're lucky if they can hear any delay at all anytime hehe.

    I've used both analog & digital delays and never thought the differences were any more than subtle.
    Of course the analog delays guys will tell you there's this huge difference - maybe to them there is.

    You need to use both to understand and forget Youtube - that's useless for any tone comparison anytime hehehe especially on delays
     
    soundchaser59 likes this.
  8. Bman20

    Bman20 Supporting Member

    Messages:
    1,425
    Joined:
    Jun 5, 2011
    Yes, go out and buy any digital delay (ie. Boss, Line 6, digitech digidelay, etc.) and borrow or buy a good analog delay (carbon copy, Deluxe Memory Man, Empress Superdelay, etc..) and A/B the two. Theyre quite different, and are very subjective as to which is in quote 'better.' Neither is better per se, just what you as a player prefer. All analogies given here are in fact accurate. Digital delays are more hi-fi and crisp. While an anolog delay is a really full, darker, sometimes more 'lush' type of effect compared to digitial. Me personally, i love what both do. I have two digitial delays and an all analog delay on my board and use them for very different things.
     
    Not Orange and Produktsumme like this.
  9. cbpickin

    cbpickin Tweed Supporting Member Silver Supporting Member

    Messages:
    6,390
    Joined:
    Jan 18, 2006
    Location:
    Central Coast, CA
    I'm not sure what analog delays you've tried, but put a DD-3 next to something like a Maxon AD900 and you will hear an enormous, undeniable difference in the repeats and the decay. The tone of the analog is much softer and rounder sounding with a more natural souding decay.
    There are several digital delays that do pretty well to simulate analog, but they are mostly going for the tape delay sound, not a Bucket Brigade sound.
     
    Produktsumme likes this.
  10. cbpickin

    cbpickin Tweed Supporting Member Silver Supporting Member

    Messages:
    6,390
    Joined:
    Jan 18, 2006
    Location:
    Central Coast, CA
    I hate to be the stickler, but the Superdelay is not analog, it is a digital delay. There are so many digital delays that model analog on the market it is hard to keep track.
    I have owned most of them and recently repurchased my favorite, the Skreddy Echo.
     
    Kronos147 likes this.
  11. midwayfair

    midwayfair Member

    Messages:
    2,047
    Joined:
    Aug 8, 2011
    Location:
    Baltimore
    This might be more than you ever wanted to know, but here's a small amount of electronics knowledge to supplement the Wikipedia article (so that it makes a little more sense why it works): One of the functions of capacitors is as timers for the discharge of electrons.

    For a good example of how this works, have you ever heard something like an amp malfunction where you get a buzz that gets louder and then all of a sudden pops? Then it does it again ... and pops again. What's going on there is a capacitor is building up charge and then, once it reaches a certain level, it discharges.

    An analog delay is, essentially, engineering this sort of function into a repeated signal. In really simplistic termsn, bucket bridgade chip, being composed of so many capacitors, can be fed a certain amount of charge on one "side" so that it takes a certain amount of time for the audio signal to pass (similar to the amount of time it took for the charge to build up before popping in our "defect" example above). By feeding more or less charge into the chip, you can control how fast it finishes the cycle. (Other parts of the circuit can control how many times it's fed the information in the original signal and so on.)

    To me, this is probably the most interesting use of small electronics components in audio circuits.

    Note that the passage of time in an analog audio circuit is the enemy of fidelity. The degradation of an analog delay signal will increase when you increase the time between the original signal and the release of the delay signal, and also with repeats beyond the first.

    Notice from this description that things are happening on a sort of scale. You have a certain amount of current, which builds to a point (that can be varied with the controls on the delay) at which something happens. This is an analog system. Another analog delay system is tape, and it's a very easy analog system to examine, because you can hold it in your hands and see exactly where the machine is repeating the original signal.

    A digital delay is built on a circuit with thousands and thousands of, simplistically, yes or no questions. The audio signal is converted to bits (1s and 0s), which carry information through the circuit. A system in which everything is based around "on" and "off" is a digital system.

    The part where the signal is converted is one reason people seek digital delays with analog bypass/dry signals, why some people can hear the difference in the decays, and so forth.
     
    MrMoose and soundchaser59 like this.
  12. vintage66

    vintage66 Member

    Messages:
    6,377
    Joined:
    Jan 28, 2007
    Location:
    Right here
    They used to sound way different-a DD-3 and a DM-2 don't sound much alike, but now, most digital delays have multiple settings and one of them is usually analog delay, and tape delay, etc. The lines are blurred more now.
     
  13. amp_surgeon

    amp_surgeon Member

    Messages:
    369
    Joined:
    Apr 11, 2008
    I think you misunderstand how a BBD works. The capacitors are not used as timers. They are used to store a voltage which is approximately equal to the signal voltage at a specific point in time. When the chip get's a strobe from the clock circuit then that charge is passed to the next capacitor in the chain, and a fresh sample of the input signal is captured by the first capacitor in the chain. There's a bit of voltage loss in the handover, which accounts for the decay. The clock frequency is also relatively low compared to the signal frequency, which accounts for the loss of high frequencies.

    A pure digital delay, without any other signal processing going, works on the same basic concept. The primary difference is that the signal is measured by an ADC and converted into a binary number, which is then stored in a memory. However, both analog and digital delays are digital in the time domain because both of them take samples at regular intervals.
     
    Not Orange and soundchaser59 like this.
  14. johnnylighton

    johnnylighton Member

    Messages:
    519
    Joined:
    Feb 13, 2009
    Location:
    So Cal
    Thanks a lot for the explanations! :)
     
  15. soundchaser59

    soundchaser59 Supporting Member

    Messages:
    10,192
    Joined:
    Dec 27, 2006
    Location:
    River City / Star City
    Thanks, that is excellent. Should be a sticky. Simplified but effective overview. Capacitors are cool.
     
  16. andrekp

    andrekp Member

    Messages:
    4,903
    Joined:
    Oct 2, 2008
    Location:
    Deep in a Cobalt mine, far from rescue.
    Well when digital delays first came about, the point was to overcome the perceived problems of the BBD ones, hence high fidelity. Later on, it was decided that the old BBD faults had some merit, do digital delays started being made that tried to sound more analog. These days, that seems the primary goal.

    The digital PT2399 chip used in a lot of delays, including DIY delays, has the fault of the BBD of not having long capabilities, maybe 3/4 of a second at a stretch, and depending on filtering built with it, can sound fairly analog. There are even one or two delays that call themselves analog, that actually use this chip.

    Note that this is an entirely different animal than using a digital processor like the FV-1, or something. It is much more akin to basically being analog. You'd never really know it's digital without knowing how it works internally.
     
  17. Help!I'maRock!

    Help!I'maRock! Member

    Messages:
    9,057
    Joined:
    Mar 12, 2008
    Location:
    on the phone
    I like digital delays that sound like analog delays. Go figure.
     
    S. F. Sorrow likes this.
  18. drbob1

    drbob1 Silver Supporting Member

    Messages:
    22,162
    Joined:
    Aug 9, 2004
    There isn't an inherent problem in BBD delays that prevents them from very long times. The problem is the clock-the clock signal is shared between all of the cells of the BBD, and it starts to lose it's sharpness as you get over 8192 cells. So it doesn't matter if the delay has a pair of 3205s or 4 3208s or 8 3207s, it still maxes out around 600 msec for a fairly low noise device.

    That's with the supplied clock. However you can build your own clock, preferably digital, that will allow no loss of sharpness as you add multiple cells, hence you can, theoretically run 17k stages for 1.2 seconds of pretty clean delay.

    I've had some great arguments about whether BBD technology is analog (because the samples are analog or seamless in the variation of the voltages), digital (because discrete samples are taken based on a clock) or hybrid. I think I'd go with the latter...

    The reason BBD delays are less bright than digital is because of the low pass filtering necessary to keep the clock noise out of the signal. Take one of the delays that allows a really long delay time (like the DMMtt or Moog that can run up to 1.5 sec) and you'll start to hear a ring modulator like whine out of the pedal. If you can speed up the clock you can avoid the frequency loss-the Marshall Time Modulator uses CCD chips and runs up to 20 kHz for the delayed sounds. As good or better than many digital delays (but WAY more expensive).
     
  19. nnnnnn

    nnnnnn Member

    Messages:
    916
    Joined:
    Jul 21, 2016
    It is how it is recorded and stored that is the difference.

    A digital delay (or other digital effect) converts the original analogue signal into a bunch of numbers. The numbers represent the shape of the original audio waveform. These numbers can then be stored and copied and each copy will be exactly the same. For you to actually hear these copies as echoes the delay pedal converts the numbers back to an analogue signal.

    To my way of thinking an analogue delay is basically any delay that manages to make copies of the signal without converting it to numeric data, i.e., any non-digital delay, but in practice people almost always mean a BBD circuit as described by others above. (So while a tape delay does produce echoes using analogue technology, it's not what people mean by "analogue delay".)
     

Share This Page