Nowadays most effect pedals are built with so-called true bypass. If you use a long line of true bypass-pedals – and the necessary patch cables – on your pedalboard, you might need a separate buffer to prevent signal deterioration, even with all the pedals turned off.
A buffer is a small amplifier circuit, which isn’t meant to raise your signal level or add volume, though, and it should not colour your tone either. A high-quality buffer amp will manage to keep your sound pristine and dynamic even through the longest of effect chains. Lehle Sunday Driver is a great example of high end buffer which evens the impedance to prevent loss of signal detail.
The theory behind true bypass-circuits is very simple: When the pedal is turned off, the whole effect circuit is taken out of the signal path. When the effect is off the input signal is hardwired to the output, completely bypassing the effect itself. The result is a natural signal that has nothing added or subtracted by the pedal’s circuit.
The term True Bypass is being bandied about by effect pedal makers as if it were a guarantee for tonal bliss. The ads tell us guitarists that a clear and pristine guitar signal can only be achieved using true bypass-pedals. In truth, nobody who is working in the field of professional audio would suggest building a large audio system without using a high-quality buffer somewhere along the line.
Vintage effect pedals are often rather noisy, unreliable contraptions, whose sound can also be unpredictable. Vintage switches can produce audible clicks and crackles. These old effects also tended to bleed into and/or colour some of the signal’s bypass tone, because the signal was always routed through the effect circuit, even with the pedal off. The result was a guitar sound that was often mangled in a multitude of ways. That was because the bypass method that was most commonly used at that time had the input connected to the effect circuit at all times, which caused the effect circuit to affect the bypassed signal.
DPDT-footswitch (double-pole, double-throw) was the first type of switch to enable true bypass. The downside with that was that the designers had to choose either true bypass without a status indicator or non-true bypass with the status indicator LED. An exception to the rule is the so-called "Rat bypass", which was introduced in the late 90's and can be found on ProCo RAT-pedals from that time, but it didn't really become an industry standard. It used a DPDT switch with an extra piece of circuitry to enable both true bypass and a status LED.
If you only need three or four pedals on your pedalboard true bypass-pedals work just great. The longer your effect chain gets, though, the more the cumulative capacitance of all the patch cables, plugs, jacks, switches, and their solder joints grows. Their combined effects on signal quality are comparable to an extra-long, cheap guitar cable. The ear will first pick up an overall loss of treble in the bypass sound.
A buffer bypass-pedal’s buffer is always switched on, also when the effect itself is turned off. This means that a buffered bypass-pedal will add something to your signal chain, even when that pedal is not in use. In a way, buffered bypass could be described as the opposite of true bypass.
A guitar cable has a capacitance value. Capacitance could be described in broad terms as how strongly a cable “sucks up” your signal’s treble content. A three-metre cable’s capacitance will attenuate a certain amount of treble, which the guitarist will compensate for using the amp’s EQ-section. If the guitar cable is much longer, plugged into a large number of effects, and the pedalboard’s output is send to the amp using another long cable, all these steps will add up to a much larger capacitance value, than if it were only the guitar, a cable and an amp.
A buffer solves the signal loss caused by capacitance by transforming the fragile, high-impedance signal coming from a traditional passive guitar into a much sturdier low-impedance signal. A buffer doesn’t make the guitar signal louder, but rather removes any electronic obstacles caused by the combination of high impedance and high capacitance. As a result the signal can travel much more smoothly through the effect pedals and on to the amp. A buffer amp allows the musician to use far longer cables – even up to ten times longer – without noticeable signal deterioration. Using a buffer on a pedalboard will make your bypass signal sound as if you were plugging your guitar straight into your amp with a short cable.
It’s hard to control your treble frequencies in a completely buffer-free environment. Have you ever noticed that using only true bypass-pedals makes you want to dial in more treble from your amp?
The usual scenario is as follows:
Whenever the guitarist turns on one of his (or her) effect pedals, the active effect circuit works as a buffer. This buffer removes the effect of capacitance caused by the long cable runs. This makes the sound noticeably brighter, which in turn causes the musician to walk over to his (or her) amp to turn down the EQ’s treble and presence controls. When the effect pedal is switched off again, the buffer-effect vanishes, leaving the signal’s top end rather muffled. Now the musician has to shuffle over to the amp to turn the treble back up; this has the makings of a vicious circuit.
You may be in need of a buffer if you feel your pedalboard’s bypassed tone is a bit muddy and lacking in detail, making you check your guitar’s tone control setting. The signal loss caused by an unbuffered system often sounds like the tone control turned down a few notches. Here’s a simple test for you to find out if you’re in need of a buffer:
Funnily enough, many musicians already have their pedalboards filled with buffers, without them even knowing about their existence or their effects on the signal. Traditionally all Boss-, Visual Sounds-, Ibanez- and DOD-pedals are buffered bypass-effects. These pedals tend to feature one buffer (or even several) that works for as long as the pedal stays connected to a battery or PSU, even if the effect is switched off. The drawback is that if you have a board filled with many Boss-pedals, your signal will be processed by all the buffer amps in all the pedals.
In this example ten Boss-pedals amount to an eye-watering amount of 20 bypass buffers, which doesn’t leave much room for your signal’s original dynamics and touch-sensitivity. The sound will be slightly artificial and sterile and, frankly, a little lifeless.
Due to the effect the impedance change has on the guitar signal, a buffer’s own sound is a slight addition of “treble clank”, meaning a slight overall treble boost. Once you’ve noticed this lift, you will always be able to pick it out. If you place your buffer wisely, this small treble lift will be “cancelled” by the signal deterioration caused by your signal chain, especially the longer cables. If you run too many buffers in your signal chain, the “treble clank” can start to stick out and even become a nuisance.
Because the effect circuit of a true bypass-pedal starts working as a buffer when the pedal is switched on, which makes the signal a bit brighter in turn, some guitar effects also start to be come more noticeable. This is one of the reasons why some pedals sound “bigger” and “better” than others. If you want a pedal to make a bigger splash soundwise, using a true bypass-effect in a buffered signal path might do the trick.
To preserve a natural signal it is advisable not to use too many buffers in your chain. It would be optimal in most cases to use two buffers – of high quality – placed evenly along the signal path. One buffer could be placed right at the front of your pedalboard, while the other could be helpful right at the output, where the signal is fed into a long cable. If you’re running a very large pedalboard, you might even want to place a third buffer somewhere in the middle. But remember: If there’s one effect you never turn off, that pedal works as a buffer, regardless of which type of bypass it uses. This pedalboard does not have buffers, but if either overdrive is on, pedal will operate as buffer.
A buffer only ever works for its output signal, it cannot enhance the signal going “backwards” from its input. If your sound is messed up right at the front end of your signal path, a buffer won’t be able to “reanimate” it. A buffer doesn’t improve the input signal, it just makes sure it is transported onwards without further loss.
This means a buffer is best placed close to the guitar. But remember that some effects won’t function properly if preceded by a buffered output. Especially fuzz-pedals and wah-wahs tend to be very sensitive to changes in the guitar signal, and they’re virtually always meant to be used with a passive guitar signal. Try out which effects sound or behave differently when placed in front of, or behind, a buffer. If possible place all those effects that want an unbuffered signal right after your guitar, and in front of the first buffer.
Signal chain for a pedalboard above:
Boss TU-3 (buffered bypass) --> Mad Professor Simble Overdrive (true bypass) --> Durham Electronics Sex Drive (buffered bypass) --> Mad Professor Dual Blue Delay (true bypass or buffered bypass) --> Strymon Flint (true bypass or buffered bypass)
This board has a few selectable buffers, which are not probably needed as there are already two buffered pedals in the board.
Buffers are often confused with boosters. This is because many manufacturers build these two very different, but similarly-named circuits into the same devices. Depending on the make and model, sometimes the buffer is always on, while in other models you can turn each effect on and off separately.
A buffer and a booster are two very different devices. While a buffer is technically an amplifier, it is a “unity-gain” device that doesn’t change your signal’s volume or sound. A booster, on the other hand, is meant to boost your guitar’s signal level (raising the voltage), and some even work similarly to an overdrive pedal. Wampler dB+ Boost/Independent buffer has an advantage of letting you decide if you want the buffer on or off, when the pedal is bypassed.
A buffer always needs a little bit of power to work, meaning no box or device which doesn’t need a battery or power supply to function can contain a buffer circuit. A buffer keeps the output signal at the same level as the input, and it needs a tiny amount of power to achieve this.
There are many different ways to build a functioning buffer. This means that buffers, like effect pedals of the same type, are not all created equal. Some top-quality buffer amps don’t even fit into the same case along with an effect.
The best pedal effect engineers also know how to design a sonically transparent and noise-free buffer. A well-designed buffer keeps the signal’s sound clear and its dynamics intact, while helping the signal on its way to the amp.
If you’re using only a limited amount of pedals, we’d recommend not to use a buffer, in order to keep the signal as natural and open as possible. Thankfully many manufacturers now produce effects, tuners and routers that include switchable high-quality buffers.
This is the ideal scenario for us pedalboard makers, because a switchable buffer means you can decide and pinpoint when to use a buffer, and when not. A well-designed buffer used in the most sensible way can turn out to be a true bypass-pedal’s best friend.
If you have purchased all the parts and components but get a feeling that you might not be up to the task after all, we can make your pedalboard for you, using the components you have bought from us. Don’t worry, we won’t let anything go to waste.
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