The world of stompboxes is seemingly fraught with confusing terminology. Much is made of true-bypass, for instance, but what is the actual advantage when it comes to your 'board and tone?
What is a buffer and what is true bypass?
A buffer is a 1:1 amplifier that changes the impedance of your signal. It’s there to counteract what happens with the interaction of various physical factors: inductance in your pickups, plus capacitance and resistance in cables, pedals, switches etc. The common terminology is that they ‘drive’ the signal, minimising signal loss.
Now, all effects pedals are buffered when they’re on. However it’s when they’re off that the principle issues arise (leaving aside fuzz which we’ll come to in a bit). True bypass is when there is no buffer in the pedal’s off state. Buffered bypass is when a buffer is in operation even when the pedal is off. It’s not necessarily a bad thing at all - the Klon Centaur, for example, is a buffered bypass pedal.
I use a ‘standard’ selection of true-bypass pedals. Do I need a buffer?
Some trial and error is needed to determine if you need a buffer. Plug everything in, leave all the pedals off and just play for a bit. Now, change nothing except for unplugging the cable from the ’board to the amp and plug your guitar straight in instead. If there’s a difference then you’re experiencing some signal loss.
This varies with cables, guitars etc, but is most noticeable with vintage-style pickups that tend to suffer when trying to ‘drive’ a lot of capacitance. A buffer could help, but so could cleaning up your signal path with a loop switcher, and/or improving your power solution.
Now repeat that process using one pedal at a time, and then using combinations of two pedals. It’s laborious, but it should help you understand if and where the tone is being changed.
The most obvious difference will be in the nature of the high-end; a strongly buffered signal will have noticeable fidelity, edge and presence that’s neither a good nor bad thing. That said, a buffer can be a key part in somebody’s tone, such as Angus Young’s.
The general advice is: 1) If you want to add a buffer, it’s usually best placed after your drive pedals. 2) Vintage-style fuzzes (Germanium fuzzes especially) tend not to like buffers in front of them. 3) Buffers after overdrive and fuzz can have an effect too, so be aware of that. 4) Once you understand what the buffer is doing to the sound, you can use it to your advantage: there is no good, bad, right or wrong!
Guidelines on signal chain
These are generalisations only. Nobody needs an additional buffer but you might want one if your sound requires some strength, edge and brightness. Adding a buffer affects the whole resultant sound, but where you place it will affect each individual pedal differently.
Delays and reverbs
Usually not a big issue with buffers unless you want to keep a very dark or analogue sound. True bypass pedals can be buffered before or after to taste. Buffered bypass pedals shouldn’t need additional buffers.
Can work well placed as the last OD in your chain, keeping its buffer after all the other fuzz or drive, but before your delay and reverb. Can make fuzzes sound harsh. Could create a conflict placement with your modulations.
True bypass pedals can gain clarity with a buffer afterwards. Buffered bypass pedals can cause issues for drives placed after.
True bypass OD
A buffer before can brighten or add edge, but the buffer is usually better placed after drives. Overdrives tend to like seeing your guitar, not a buffer.
Usually hate buffers before them. Germanium fuzzes usually need to be first after the guitar. Brighter or harsher with a buffer after.