Fig. A
In my previous State of the Stomp ["The Shocking Truth About Ground Loops," October 2021], I discussed how ground loops can be formed between the amplifiers in a multiple amp setup, and how to safely address them with an isolation transformer. As a brief reminder, a ground loop is created whenever two electrical circuits that theoretically have the same ground potential actually have a non-zero potential between them in practice, and that often results in hums and buzzes that are harmonically related to the mains voltage frequency in your part of the world.
Oh, how I wish that was the only means of making a ground loop! Tennyson certainly didn't have ground loops in mind when writing that nature was red in tooth and claw, but as someone who has built guitar rigs for around 25 years, it is hard to shake the idea that they serve a merciless and maniacal natural force that actively resists the pristine and well-ordered world of quiet, toneful pedalboards and rack systems.
These loops are made by the way we wire our stompboxes and the environment around them. The ones in this month's ground loop fest may be a bit more identifiable than the loops in the multi-amp scenario. In that case, part of the loop is hidden in your venue's installed power cabling. This time, we're going to discuss loops that exist wholly and entirely in your pedalboard itself.
"Tennyson certainly didn't have ground loops in mind when writing that nature was red in tooth and claw."
The first ground loop we'll discuss is a potential loop created by using daisy-chain power cables, where one power supply feeds multiple pedals. In this setup, you can make a loop via the power cables connecting two pedals and the audio cables connecting them. There is a clear ground path in Fig. A that goes from stompbox to stompbox via the audio cables. If that were the only path, there would be little chance for a loop to be formed. But if you add in the ground path made by the power cables, you can now see a circuitous path that connects the first and last pedal through the audio cables and then doubles back through the power daisy chain. This circle of wire is our loop.
A second loop type is shown in Fig. B. Most loop switchers tie the ground connections of the send and return jacks together, and when the loop switcher is connected to a stompbox, the audio cables make a ring of ground conductors. So each loop switcher loop can actually make a ground loop. Yay!
There are countless loop switcher-equipped boards out in the world. Why don't all of them hum? Ground loops can generate hum when they are driven by an outside electromagnetic field. (Bill Whitlock's Audio Engineering Society treatise "Ground Loops: The Rest of the Story" gives great theoretical and experimental explanation of EMF—electromotive force—induced ground loops.) When the ground looped cable encircles an EMF field, that field can develop a current in the wire that can translate into audible hum in your rig. So if your power/audio cable loop or your loop switcher loop wraps around a power supply transformer or a high-current, noisy power cable at a venue or in your home, you may get an induced hum that you can hear in your amplifier's output.
Fig B.
So, what can be done? Fig. A shows how daisy-chained power can make a giant ground loop susceptible to picking up stray EMF. Using isolated power for every pedal will break this loop and keep it from generating noise. If you must share power amongst pedals on your board, make sure they are next to one another in your signal chain so that the loop size (and associated hum) is minimized.
For Fig. B, the cables to and from the pedal can be as short as possible and run as close to one another as possible. This too will decrease the area encircled by the loop and commensurately minimize the induced current. Special care should be taken to make sure looping cables do not surround or run near power supplies or wall warts. The type of power supply can make a difference as well, since those from Truetone or Strymon switch at higher frequencies that are less likely to be induced in the first place, and less likely to be heard if they are.
While this is hardly a 100 percent complete picture of the cruel world of ground loops, you hopefully are armed with enough knowledge to have insight into exactly what could be causing those wayward noises and buzzes in your rig and how to clear them out to make way for a much more gratifying set of buzzes and noise.
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Naturally, every recording Eddie Van Halen ever played on has been pored over by legions of guitar players of all styles. It might seem funny, then, to consider EVH solos that might require more attention. But your 100 Guitarists hosts have their picks of solos that they feel merit a little discussion. Some of these are deep cuts—get ready for some instrumental bonus tracks and Van Halen III mentions—and some are among the biggest radio hits of their time. Just because their hits, though, doesn’t mean we don’t have more to add to the conversation.
We can’t cover everything EVH—Jason has already tried while producing the Runnin’ With the Dweezil podcast. But we cover as much as we can in our longest episode yet. And in the second installment of our current listening segment, we’re talking about new-ish music from Oz Noy and Bill Orcutt.
Tinkering with theSDE-3 Dual Digital Delay suggested a similar, possibly enduring appeal. As an evolution of the Roland SDE-3000rack unit from the 1980s, it’s a texture machine, bubbling with subtle-to-odd triangle LFO modulations and enhanced dual-delay patterns that make tone mazes from dopey-simple melodies. And with the capacity to use it with two amps in stereo or in panning capacity, it can be much more dimensional. But while the SDE-3 will become indispensable to some for its most complex echo textures, its basic voice possesses warmth that lends personality in pedestrian applications too.
Tapping Into the Source
Some interest in the original SDE-3000 is in its association with Eddie Van Halen, who ran two of them in a wet-dry-wet configuration, using different delay rates and modulation to thicken and lend dimension to solos. But while EVH’s de facto endorsement prompted reissues of the effect as far back as the ’90s, part of the appeal was down to the 3000’s intrinsic elegance and simplicity.
In fact, the original rack unit’s features don’t differ much from what you would find on modern, inexpensive stompbox echoes. But the SDE-3000’s simplicity and reliable predictability made it conducive to fast workflow in the studio. Critically, it also avoided the lo-fi and sterility shortcomings that plagued some lesser rivals—an attribute designer Yoshi Ikegami chalks up to analog components elsewhere in the circuit and a fortuitous clock imprecision that lends organic essence to the repeats.
Evolved Echo Animal
Though the SDE-3 traces a line back to the SDE-3000 in sound and function, it is a very evolved riff on a theme. I don’t have an original SDE-3000 on hand for comparison, but it’s easy to hear how the SDE-3 bridges a gap between analog haze and more clinical, surgical digital sounds in the way that made the original famous. Thanks to the hi-cut control, the SDE-3’s voice can be shaped to enhance the angular aspect of the echoes, or blunt sharp edges. There’s also a lot of leeway to toy with varied EQ settings without sacrificing the ample definition in the repeats. That also means you can take advantage of the polyrhythmic effects that are arguably its greatest asset.
“There’s a lot of leeway to toy with varied EQ settings without sacrificing the ample definition in the repeats.”
The SDE-3’s offset control, which generates these polyrhythmic echoes, is its heart. The most practical and familiar echos, like quarter, eighth, and dotted-eighth patterns, are easy to access in the second half of the offset knobs range. In the first half of the knob’s throw, however, the offset delays often clang about at less-regular intervals, producing complex polyrhythms that are also cool multipliers of the modulation and EQ effects. For example, when emphasizing top end in repeats, using aggressive effects mixes and pitch-wobble modulation generates eerie ghost notes that swim through and around patterns, adding rhythmic interest and texture without derailing the drive behind a groove. Even at modest settings, these are great alternatives to more staid, regular subdivision patterns. Many of the coolest sounds tend toward the foggy reverb spectrum. Removing high end, piling on feedback, and adding the woozy, drunken drift from modulation creates fascinating backdrops for slow, sparse chord melodies. Faster modulations throb and swirl like old BBC Radiophonic Workshop sci-fi sound designs.
By themselves, the modulations have their own broad appeal. Chorus tones are rarely the archetypal Roland Jazz Chorus or CE type—tending to be a bit darker and mistier. But they do a nice job suggesting that texture without lapsing into caricature. There are also really cool rotary-speaker-like textures and vibrato sounds that offer alternatives to go-to industry standards.
The Verdict
The SDE-3’s many available sounds and textures would be appealing at $219—even without the stereo and panning connectivity options, a useful hold function, and expression pedal control that opens up additional options. The panning capabilities, in particular, sparked all kinds of thoughts about studio applications. Mastering the SDE-3 takes just a little study—certain polyrhythms can be dramatically reshaped by the interactivity of other controls and you need to take care to achieve identical results twice. But this is a pedal that, by virtue of its relative simplicity and richness and breadth of sounds, exceeds the utility of some similarly priced rivals, all while opening up possibilities well outside the simple echo realm
