WTF is Bucket Brigade Technology?

Guitarist love to talk equipment and use impressive guitar lingo.  Lately the MXR Carbon Copy analog delay is creating a buzz among guitarist who boasts its “bucket brigade technology”.   What is bucket brigade technology besides a sexy phrase to use when talking about delay pedals?

In the old days a bucket brigade was how firemen put out fires.  They lined up holding buckets and passed water from the water source to the fire.  As the water got passed along there was some spillage from the continuous dumping and catching  of water from bucket to bucket.  By the time the fire actually received the water, the bucket was far from full.   To cover more distance between the water source and the fire they either had to add more firemen or spread the existing firemen out forcing them to have to run to the next fireman.  Either case would result in more spillage and  less water in the bucket by time it got to the fire.

Now let’s replace the water source with our guitar, the firemen with a bucket brigade circuit and the fire with our guitar amplifier.  When we play a note on our guitar we send a signal to the bucket brigade circuit.  A bucket brigade circuit consist of a series of capacitors that store the guitar signal then pass it on to the next.  Just like a line of buckets isn’t a very efficient way of moving water, capacitors aren’t very efficient in moving along a guitar signal as they tend to leak.  The more times your signal gets dumped from one capacitor to the next the more signal leakage there is resulting in more and more high frequency loss.   Also, like the firemen who had to spread out to cover more ground requiring them to run with the bucket of water to the next bucket resulting in water being spilled, increasing the space between delays causes  signal leakage too.  The more you increase the delay time, the longer the capacitor has to hold on to the signal before passing it on.  The longer the capacitor holds on to the signal, the more time it has to leak some of the signal resulting in high frequency loss.  Depending on how many repeats or how long the delay time is, once the delayed signal reaches the amp it could be missing frequencies from 1k on up.

If your house was on fire I doubt you would feel relieved if a bucket brigade showed up, but many guitarists do prefer the old bucket brigade technology analog delays over modern digital delay units.  One of the reasons I prefer an analog delay in most situations is that it doesn’t stomp all over my playing.  Its lack of high frequencies make the repeats sit back in the mix, adding fullness and depth but still allowing my guitar’s original notes to cut through.

6 Comments on “WTF is Bucket Brigade Technology?”

  1. austexcal says:

    great explainer

  2. […] change the sound.  But, is that a good thing?  In most cases, NO!  A higher voltage on an old bucket-brigade analog delay, for example, may increase the signal to noise ratio a smidgen, while also boosting and cleaning up […]

  3. Rob says:

    Thank you so much for this! Very clear explanation. I’ve been searching the web for an answer of what bucket delay is and this is the first that actually explains it!

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