Analog Delay Pedals: What's the Big Deal?

What's the "magic" behind our love of analog delay pedals?
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In broad swathes of the consumer audio world “digital” has long been the watchword for clean, clear, precise, and perfect sound. Why is it, then, that so many guitarists continue to go nuts for analog delay? Can it really still outstrip the best that digital has to offer?

Part of our frequent predisposition toward analog delay pedals circles back to old truths about guitar tone in general: distortion adds depth, imperfection adds character. Just as we rarely like the sound of a guitar played through a high-fidelity audio amp with extremely low total harmonic distortion (THD), we often find that an echo effect with a little fur and flutter on the repeats simply sounds better—whether or not we pause to analyze how accurate that delayed signal actually is. The slight distortion in many analog delays is often heard as a good thing, an artifact that thickens up the sound. Digital delays can distort too, but in its native state, this doesn’t occur in a way that is very appealing.

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MXR M-118 Analog Delay, one of the early analog delay pedals to use the Bucket Brigade Device chip.

To a certain extent, the quality or lack thereof of many of the more affordable (though often still quite expensive) early digital delay pedals on the market in the mid ’80s compounded this analog/digital dichotomy. Not only did these units sport fairly low resolution (a.k.a bit rates) compared to what is more commonly used today—say 8 bits or 16 bits versus 32 bits—but the rest of the technology used around their digital hearts to produce the echo effect didn’t help matters much.

Digital delay does its thing, in basic terms, by splitting the signal at the input, running one path through an analog-to-digital (A/D) converter, sampling it, and blending it back with the dry signal at a desired delay time after translating it back through a digital-to-analog (D/A) converter. Voila: echo! When this is done at a low resolution, however, and with little extra thought to the timbre and character of the sound, the delayed signal can often sound cold and slightly harsh.

Analog delay happens in much the same way, essentially, except that the entire delay-line portion of that split signal path is produced with analog technology, which also means that no conversion of the signal out of the analog realm and back again is required. The original and most beloved form of non-mechanical (i.e. non-tape-generated) solid-state analog delay technology of the mid ’70s onward was the so-called “bucket-brigade delay,” the echo at the heart of early delay pedals by Electro-Harmonix, MXR, Ibanez, and others.

Enabled by Bucket-Brigade Device (BBD) chips that, essentially, took a signal in at one end and passed it along to the other via several stages at a desired delay time, these units had a warm, rich sonic quality with a smooth, furry texture when they clipped. In short, when the echo signal came out the other end in less-than-pristine condition, it often actually sounded better to guitarists than it did going in.

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Digital has come a long way in the three decades since its infancy, though, and the ways in which more creative effects designers today are using the technology to process delays has come even further. Essentially, manufacturers such as Strymon, TC Electronic, Eventide, Line 6, Wampler, and others have made digital delay sound much more appealing to guitarists’ ears by doing what the digital-audio realm often does in respect to guitar tone: copying the sound of analog. Vastly improved resolution, better A/D and D/A converters, and all-analog side chains have been teamed with accurate emulations of what different types of analog echoes really sound like. The result is not only a great-sounding digital effect, but in many cases, one with enormous versatility and tweakability, enabling you to hop from warm, grainy BBD delay; to rich, warbly tape delay; to sharp, pristine digital delay at the punch of a preset button.

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Meanwhile, while analog delay still sounds great, some of the best-loved renditions are virtually in their death throes, thanks to the ever-decreasing availability of the preferred BBD chips used to build them.

Fortunately, amid all this debate, it’s mainly just we guitarists who fret over such nuances. To the ears out in the audience, an echo is an echo is an echo. Maybe that little bit of warm and fuzzy we hear in just the right kind of echo makes us better players, though, and that’s really what it’s all about.