Why buffer for every pedal?

[nguitar12]

As I understand a buffer is a circuit that boost the guitar signal so that it will process by the circuit. However if we use buffer in every pedal the signal will become higher and higher and eventually distorted. Isn't it? Also as the guitar signal is passing through more circuit it will loss the tone. So basically how the pedal design will overcome this problem?

[R.G.]

To answer the question in the title of your post, there is a buffer on every pedal because it is possible that any pedal will have a guitar as its only input. When that happens, the guitar signal will lose treble more than bass because of the guitar pickup's high inductance unless the pedal input has a high impedance, in the range of 1M or more. So pedal designers must make sure that their pedal has a high impedance just in case it is used with only a guitar in front of it.

The best system-wide solution would be a buffer on the guitar itself, but no one will do that because not all guitars can be equipped like that. The second best solution would be a buffer plugged into the guitar before the cable, but guitarists will not bother with that. The third best solution would be one and only one buffer at the input to the pedalboard. That is possible and practical, but guitarists do not use pedalboard systems, they insist on buying any random pedal that takes their fancy, so no system solution is going to be used by guitarists in general.

This leaves us with the requirement that each pedal provide a buffer on its own because it *might be* the first pedal in a chain.

As I understand a buffer is a circuit that boost the guitar signal so that it will process by the circuit. However if we use buffer in every pedal the signal will become higher and higher and eventually distorted. Isn't it?

No, it isn't.

Buffers may or may not boost a signal *voltage*. The vast majority of buffers used in pedals have unity gain or slightly less so they do not boost signal voltage at all. They are there to boost the available signal *current*, which does not lead to the signal becoming higher and higher and eventually distorted.

Also as the guitar signal is passing through more circuit it will loss the tone.

That is not certain. Whether tone is lost or not depends on how well the circuits are designed for the job.

So basically how the pedal design will overcome this problem?

By good understanding of what the circuits do and by careful design.

[GibsonGM]

By good understanding of what the circuits do and by careful design.    < words to live by.

SOME manufacturers add a buffer in every pedal, like Boss.  This is just how they roll...probably they feel it allows them to make a consistent product without knowing what the user is putting before and after their product.  Plus, it very much agrees with their electronic switching rather than "true bypass" - eliminates a potential problem that could arise due to their soft switching scheme.  And you get a free buffer when the pedal is disengaged 

The need to buffer (or not) comes from knowing what is feeding your equipment (pedal, amp, chain of pedals...). "Understanding...and design".  We want a BRIDGED impedance between them.  Not likely to get that, so we settle for 'low output impedance feeding high input impedance'.   R.G. has some great info on this on his site at "GEOFEX", link above....   A buffer can help make this happen by offering a very high input impedance and a low output impedance that is capable of SOURCING current for whatever follows it.  This is an important point....circuits TAKE current - they draw it, like a sponge.  The circuit doing the DRIVING doesn't push current out.     

So, a buffer's ability to SOURCE for say, a tone stack, means that what came before the buffer is essentially unchanged as the buffer happily feeds the circuit down the line the current it needs.  Without this, the tone stack may LOAD DOWN the circuit before it, trying to pull current from a source that just can't give enough.   The result of that is a drop in high frequencies which are more 'vulnerable' to this, plus an overall drop in level which you don't want.  Could also add noise picked up from the environment as your levels drop.   In short - it is making CURRENT available to what follows, often with a slight DROP in voltage, but that's more than OK as what they do is NOT voltage amplification but current amplification...

Some people need NO real buffer in their chain (I don't use too much stuff that has them, for instance, with no troubles as my 'designs' already offer high input impedances etc.).  If your input impedances are high, and output impedances low, you could be JUST fine.   But if you run many pedals, a lot of cable - that can take some highs away and make things "sluggish" sounding - so then you might consider adding a buffer.    That's a 'user preference', definitely something to try out to see what it does, as part of your 'available toolkit',  but not needed in EVERY pedal or whatever you have....sometimes a buffer can make a tone too brittle, depending on what variables are present...

[Mark Hammer]

The original question comes from the perspective of someone who anticipates either designing or building their signal path around THEIR anticipated needs.  Entirely legitimate perspective.

The manufacturer predicates design around the worst-case scenario...which includes end-users having no knowledge about input impedance, etc.  Also legitimate.

[Digital Larry]

A fair number of fuzz pedal designs expect to be driven from a passive guitar and don't like being driven by low impedances.  These can usually be identified by the first transistor that the signal sees having its emitter directly connected to ground.

[tubegeek]

We want a BRIDGED impedance between them.  Not likely to get that, so we settle for 'low output impedance feeding high input impedance'.

Isn't "low output impedance feeding high input impedance" the definition of bridged impedances?