True Bypass, Buffers and Long Cables - Nerd Talk

Pedals are such a useful tool and creative aid for guitarists. With unique and interesting pedals being developed constantly as well as upgrades to existing effects, it's no surprise that guitarist's signal chains are getting longer, which no doubt has an effect on the overall tone. Whether your pedals are "true bypass" or not, the fact that you are not only increasing the length of cable your signal has to travel through, and also making it go through a plethora of extra electrical components and trusting the cable connectors are transferring the signal accurately, there is bound to be degradation in audio quality.

A good place to start is to define what a buffer is. In basic terms, a buffer is an amplifier which does not affect the output volume but changes the output impedance of the signal. All components of your signal chain have elements of capacitance, impedance and resistance, but what does this mean?

Capacitance can be demonstrated by a tone control on an electric guitar. It is basically a high pass filter, letting high frequencies pass through. Depending on how it’s used in the circuit, the capacitor does different things. In the tone circuit the pot, which is a variable resistor, varies the amount of resistance for that capacitor to send the signal to ground. The less resistance it has the more top end frequency goes to ground, making the sound get duller.

Capacitance in cables is the same, except on a much smaller scale. Cables have resistance because of the relationship between the core of the cable, which carries the signal, and the outer shield. The higher the distance between the core and the shield the lower the capacitance, and many high end cable companies quote the capacitance of the cables in their marketing. Every time the cable length is doubled, the capacitance is doubled. Basically there's a natural relationship between the length of the cable and how dull the guitar sounds.

Onto impedance; different pickups have different output impedance. Single coil pickups tend to have lower output impedance than humbuckers. The lower the output impedance of the guitar pickups, the more it drives the capacitance of the signal, meaning the sound you get out of your amplifier is brighter. If you have a high output humbucker it could sound quite dark, but a low output pickup, such as the gold foil pickups which are quite popular at the moment and have a very low output impedance have a very bright top end.

The effects can be easily tested by increasing the length of your cable and putting a few inactive true bypass pedals in the signal chain - if you A/B this tone with direct into the amplifier, you should notice a duller sound through the longer signal chain.

A buffer takes the output impedance of the guitar's pickups and changes that to a much lower impedance which will drive the capacitance of the cable. A good buffer will mean that using an 100m cable through all your true bypass pedals into your amplifier will sound the same as plugging directly into your amplifier with a sensibly short cable.

Some pedals have built in buffers. Obviously these are of varying standards depending on the pedal, but these do a similar thing in reducing the output impedance whether the pedal is active or not. A true bypass pedal, when inactive, completely bypasses all circuitry in the pedal, but turning on a true bypass pedal will reduce the output impedance, bringing some top end back in compared to the inactive sound. Even with the tone of the pedal down low there is a top end to the tone which you almost feel more than you hear (although it is audible).

Buffers are amplifiers which have a signal to noise ratio. If going guitar direct into amplifier is your desired tone, a really good buffer will retain that, even if you wanted an 100m cable. If you have 6 buffered bypass pedals in a row, you will have good capacitance but there will be other problems. You’re effectively stacking amplifiers into each other.

Placing a buffer in different areas of your pedalboard will affect the tone differently. If you have a buffer at the start of your pedalboard, it helps maintain the signal going through all of your pedals, meaning they all receive exactly the same signal. A lot of people like to place the buffer after the overdrives and distortions, using the mindset that the designer of the pedal designed it using guitar plugged straight into the pedal. When you use a germanium transistor overdrive/ or fuzz pedal, having the buffer before the pedal introduces a very harsh treble to the sound - you might want that sound, but it does alter the tone drastically. Germanium fuzz pedals especially can be sent into unusable territory with a buffer preceding it.

It is worth saying to end on, you can choose to use or not use buffers or long cables to alter your tone according to what you like. Brian May's signal chain uses a guitar with very bright single coil pickups through a treble booster into Vox AC30s, a very bright rig, however he uses long coil-y cables which by their nature roll some of the top end off. It retains a naturally bright sound, but tames the harshness. The same applies for if you had a muddy sounding Les Paul, try out a buffer and see if it makes your tone more clear and glassy.

Hopefully you've enjoyed this nerd talk about true bypass, buffers and long cables! Do you use a buffer in your signal path? Let me know in the comments! As usual remember to follow The Pick on social media, links are down the side.