Maxon AD999

I’m on a bit of a kick recently and now you have to know about it with some enthusiasm. It almost seems too early to revisit Maxon, but some time ago I found this thing at the back of the cabinet, plugged it in and remembered why I love it.

I’ve covered the basics of analog delay thoroughly in the pages of this blog, so I’ll sum up the story: the bucket-brigade device (BBD) was invented in 1969 and found its way into pro audio circuits shortly thereafter. When they debuted, the chips were expensive and the guitar devices in which they were found were suped up with onboard transformers in lieu of batteries. This upped manufacturing costs significantly. Coupled with the relatively large physical size of the delay circuit itself, the space and price concerns produced beastly vintage delay boxes such as Electro-Harmonix’s Deluxe Memory Man that consequently had a relatively puny 300 milliseconds of delay time. Unfortunately for the consumer, offering more delay time meant more BBD chips and accompanying circuitry, more external clock noise correction, and subsequently tons of real estate.

When the MN3005—the most famous and common chip in BBD history—went obsolete in the mid ‘90s, there was an arms race among effects manufacturers to secure the remaining supply. Maxon themselves were one such unit, with an astounding two MN3005 chips per pedal in the company’s AD-900 (with a hyphen). Along with some other companies, Maxon kept making their products until their stash was depleted, and those without stock made do with other devices—including digital.

There were some substitute devices available but nothing really compared to an MN3005. It wasn’t until Maxon thought “hey, what if we made our own BBDs?” that the company released the AD999, one of the best analog delays ever made.

In MN3005 designs, there is a clock frequency that bleeds into the audio path and is subsequently filtered successively. It is this filtering succession that makes analog delay degrade and “warm up” as repeats continue. Designing an all-new custom BBD chip from the ground up meant that Maxon could set their own clock frequency for the filtering to be built around the pedal instead of the opposite.

One hurdle for would-be IC fabbers is the sheer quantity one must order for it to even make sense. It’s this minimum order quantity that stunts many budding monolithic circuit designers. However, Maxon is distributed worldwide, and the circuit uses an unreal eight BBDs and three clock drivers. At that many chips per unit, Maxon paid the piper and made a boatload of these.

With that many delay chips, the AD999 serves up a ridiculous 900 milliseconds of pure analog delay. Only the Moog MF-104Z—the middle child between the MF-104 and MF-104M—topped the AD999 at 1000 milliseconds, but it was huge, used a funky power supply and was about three times the price upon release (if you’re looking for a scare, check out how much any of those Moog delays are going for on the used market). The choice for many was clear, even though the Moog sounds outstanding.

After all that, you might be wondering how the AD999 actually sounds and what makes it different from other analog delays. That’s a great question, one I would probably have when being presented with a three-knob analog delay. The difference is in the thoughtful design and expertly voiced clock filter. When stretching delay times to the maximum, the signal suffers in tandem, with subsequent repeats sounding frail and withered. Maxon realized this and implemented a handy recovery gain circuit that keeps the signal present even at longer delay times. It’s a cool trick and it makes everything pop when you’re getting lost in space.

Some of my favorite delays are extremely dark, such as the DOD 680. After just a repeat, the 680 has dragged your signal through the mud. And I love that, as an effect. But sometimes I want my delay to be on for long periods of time and become a part of my base tone. As time went on, we found that some genres depend on it, such as post-rock, a largely instrumental genre that peaked right around the time the AD999 was released. But above all, the AD999 checks all the boxes of being easy to use with enough bells and whistles to enhance one’s tone without adding complication.