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All About True Bypass Pedals

January 30, 2014
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DSC_8397IMAGINE A WORLD WITHOUT TRUE BYPASS: NO doubt it would be a dark, dull, muddy place, inhabited only by the wan, hollow sound of tone sucking as far as the ear can hear. Or so a great many pedal manufacturers would have you believe, anyway. The fact is, true bypass is a great boon in certain situations, but not universally desirable in others. As with so many aspects of music technology, the benefits depend on where and how you use the feature. Let’s first take a brief look at what true bypass really is, and what the alternatives are, then we’ll explore its function on a real-world pedalboard.

Effects pedal manufacturers use the term “true bypass” to describe pedals equipped with switching that connects the input directly to the output when the effect is off or “bypassed,” effectively sending the guitar signal along its merry way as if no pedal were even there. This feature, which has become a major selling point for many stompboxes, is also sometimes called “hard-wired bypass,” although that’s a bit of a misnomer, as the input isn’t truly hard-wired to the output (it isn’t soldered from jack to jack), but is achieved with a switched connection. Achieving true bypass in a pedal where an LED on/off indicator light is also needed requires a more complicated switch known as a “three-pole, double-throw” (or 3PDT for short). Such a switch has two positions—on and off—but each of those makes three circuit connections within its housing. As such, instead of simply turning the effect part of the circuit on and off, as simpler switches do, true bypass pedals simultaneously switch the incoming guitar signal from effect circuit to output and switch the indicator LED from on to off. Some pedals also achieve true bypass through electronic switching, using a different type of switch to trigger a relay that flips the signal path from circuit board to output. The benefit of the true bypass circuit is that it sends your guitar signal straight along to the amp, or the next stage in the effects chain, without routing it around part of the pedal’s circuitry, as is what happens with non-true-bypass pedals, which have switches that simply turn the effect circuitry on and off, while the signal still runs through the remainder of the circuit before reaching the output jack.

 

gp0310_gear8395This Fulltone Catalyst sports a 3PDT switch (just above the battery).

The true bypass’ promise of pure, unfettered tone seems like a great thing, so why would we ever want anything else? In the face of many older-style effects pedals that sap your tone even when “off,” true bypass is indeed a revelation. But most good contemporary non-true-bypass pedals use a buffer—a small, unity-gain preamp stage— to condition your guitar signal and help it survive the rest of its journey through the circuit, and the rest of the way to the amp, without level or tone loss. A poor buffer can deplete the signal in and of itself, but a good one can potentially help your tone make it to the amplifier sounding truer, bolder, and more like its original self than it would by passing unbuffered down a long guitar cable.

If you only use two or three effects pedals and short cables from guitar to pedals to amp, true bypass pedals might indeed present the best option.

Say you use seven to 10 pedals on your board, however, which is not an uncommon scenario, a long 20' cable from your guitar to the first pedal on the board, several more feet of cable to get around the board, and another 20' cable from the last pedal to your amp. Any guitar cable will impose a load on your guitar signal, and cables of more than 20' present a higher load that can really start to be heard as a loss of highs and a slight loss of clarity overall. Two of these back-toback can really muddy the waters, and consider what all the gubbins between them on that crowded pedalboard must be doing. With eight true-bypass pedals on the floor, your signal has to navigate 16 input and output jacks, 16 internal 3PDT switch terminals, and several inches of internal wiring in addition to the connecting cables themselves. Add it all up, and it can present a significant load to your signal—and mean a lot of tone sucking from this pedal rig that you carefully assembled with the specific intention of avoiding tone sucking. If you have even a handful of true-bypass pedals and a couple of long cables you can try this for yourself. Connect it all to the amp, switch all pedals to off, and play a while; now unplug your first cable and go straight to the amp. Hear a difference? Players who often have at least one pedal turned on most of the time will notice the tone sucking less, because, when on, the effects circuits within most truebypass pedals inherently present a form of buffer to your signal. When they’re off, though, you’ve got nothing but upwards of 50' of wire from guitar to amp. Now, if you have a good-quality buffered pedal, or a clean, linear preamp that you can set to unity gain (that is, where the output level is equal to the input level), put that in front of your multi-pedal setup and check it again. Chances are your tone will sound a lot closer to the way it does with one cable straight into the amp.

In an ideal world, most of us would love to be able to plug straight into the amp with a relatively short cable for our clean, unaffected tone, then run through just the pedals that are switched “on” for the effected tones. This is essentially what professional switching systems used by many touring musicians do, but these rigs still use buffers to help drive long cable runs. In fact, you’ll find very few touring professionals working without a good buffer in their signal chain, other than, perhaps, a few diehard, old-school minimalists with only a pedal or two and short cable runs—and these guys are most likely playing smaller venues where such a setup will work. For most workaday club-gigging guitarists, a big expensive switching system that takes up several square feet of real estate on the stage floor and requires three or four sliding drawers full of pedals in a road case in the backline just isn’t practical. Such players, when they still need to run a plethora of effects pedals, usually do well to employ a carefully placed buffer somewhere in the chain.

Often a buffer works well in the first position of a crowded pedalboard, where it will condition the signal right at the start to help it along its ride. If you have one particular true-bypass pedal that you like to use first in the chain because of the way it interacts with your guitar’s volume control, you might prefer to retain that one unbuffered, and place the buffer later in the chain. Also, if you only use a handful of pedals, but still want a buffer to help drive the signal run down the final long cable to the amp, there’s nothing wrong with placing a buffer stage last.

It isn’t All About’s place to recommend specific products, and you’d do best to assess the quality of different buffers for yourself. You might find you already have a perfectly good buffer on your pedalboard, since not all new pedals these days are true bypass, nor are many from longer-established makers. The likes of Boss, Ibanez, and other major names have always built non-true-bypass pedals with small buffer stages, while newer maker Visual Sound swears by the inclusion of a good buffer, and boutique manufacturer Barber Electronics offers a small buffer circuit that can be retrofitted to many of its existing pedals. High-end British pedal designer and switching system manufacturer to the stars, Pete Cornish, has long insisted on the inclusion of buffers in his devices, and Roger Mayer has designed many of his newer pedals to give the player the option of either a true-bypass output or one of two (or two simultaneous) buffered outputs, all in the same enclosure. Various companies offer dedicated buffer/preamp units that will do the job well, and many of the more complicated amp switchers carry buffers, too. Also, if you’ve got several pedals that you tend to only use one at a time, you can group them and keep them out of the signal path when switched off by placing them in the loop of a truebypass loop-selector—another great way of cutting down your cable run. Experiment with your buffer placement and pedal order, listen closely to the results—A/B’ing frequently with your guitar’s straight-in tone—and go with whatever works best for you.

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