What Is A Buffer?

[andergtr]

Its like a tiny amplifier I think. It takes the hi impedance signal and levels/isolate it to a "unity".

So having a bunch of true bypass pedals, they and the cables between will dampen the guitar signal, maybe noticeable by some high end loss. But a buffer keeps the signal even through all of those. Not really sure now, as it was many years ago I even thought about it. But placing a Boss pedal (those have buffers active when effect is off) first keeps the signal integrity through the whole chain of pedals.

the boss buffers are awful, though. sounds very different than a dedicated outboard buffer.

 

[andergtr]

I believe active pickups is like a buffer

yes, active pickups are low impedance so no need to convert low impedance to low impedance.

 

[jay mitchell]

A "buffer" is an active device that ideally preserves the signal from its input and can drive loads that would cause alterations in the frequency content of the signal if the input device (guitar here) had to drive them directly. A buffer may or may not have unity gain. Some important points follow.

1. Guitar pickups have extremely high output impedances. A typical humbucker pickup can have peak impedances (usually at frequencies >8kHz) exceeding 400Kohms. SC pickups have lower, but still very high, output impedances.
2. Most, but not all, guitar amps have very high input impedances, typically 1Mohm.
3. Lots of stompboxes - especially "vintage" ones - have much lower input impedances than tube amps.
4. Early stompbox bypass switches were SPDT types. The output of the device could be switched to see either the processed signal or the guitar's output, but the guitar's output was always connected to the stompbox input. This loaded the signal in a way that could completely change its character. Early Dunlop Crybaby wahs were one example. With the wah switched off, the signal from the guitar was darker, duller, and weaker than it would be when connected directly to the amp. The solution to this is a DPDT switch (aka "true bypass"), but this type of switch was not available in footswitch form until sometime in the 1970s or later.
5. If you played through a series of stompboxes with SPDT bypass switches, each added device would further load the guitar signal, even when bypassed. It didn't take many boxes for this to become untenable.
6. A buffer ideally has input impedance that matches your tube amp and a much lower (ca. 1Kohm or less) output impedance. If your amp has a different (usually lower) input impedance than 1M, adding a 1Mohm-input-impedance buffer will alter the sound from what you're accustomed to.

In a perfect world, a buffer at the beginning of a pedal chain will allow the guitar's unaltered signal to drive any number of stompboxes without being loaded down at any frequency. When the character of an effect depends in some way on the loading effect of its input - as, for example, a number of fuzz boxes do - then using a buffer will change the effect's behavior, and the changes may not be to your liking.

FYI, guitar pickups are all intrinsically passive. "Active" pickups are simply passive pickups with buffers built into their shells.

 

[jellodog]

A "buffer" is an active device that ideally preserves the signal from its input and can drive loads that would cause alterations in the frequency content of the signal if the input device (guitar here) had to drive them directly. A buffer may or may not have unity gain. Some important points follow.

1. Guitar pickups have extremely high output impedances. A typical humbucker pickup can have peak impedances (usually at frequencies >8kHz) exceeding 400Kohms. SC pickups have lower, but still very high, output impedances.
2. Most, but not all, guitar amps have very high input impedances, typically 1Mohm.
3. Lots of stompboxes - especially "vintage" ones - have much lower input impedances than tube amps.
4. Early stompbox bypass switches were SPDT types. The output of the device could be switched to see either the processed signal or the guitar's output, but the guitar's output was always connected to the stompbox input. This loaded the signal in a way that could completely change its character. Early Dunlop Crybaby wahs were one example. With the wah switched off, the signal from the guitar was darker, duller, and weaker than it would be when connected directly to the amp. The solution to this is a DPDT switch (aka "true bypass"), but this type of switch was not available in footswitch form until sometime in the 1970s or later.
5. If you played through a series of stompboxes with SPDT bypass switches, each added device would further load the guitar signal, even when bypassed. It didn't take many boxes for this to become untenable.
6. A buffer ideally has input impedance that matches your tube amp and a much lower (ca. 1Kohm or less) output impedance. If your amp has a different (usually lower) input impedance than 1M, adding a 1Mohm-input-impedance buffer will alter the sound from what you're accustomed to.

In a perfect world, a buffer at the beginning of a pedal chain will allow the guitar's unaltered signal to drive any number of stompboxes without being loaded down at any frequency. When the character of an effect depends in some way on the loading effect of its input - as, for example, a number of fuzz boxes do - then using a buffer will change the effect's behavior, and the changes may not be to your liking.

FYI, guitar pickups are all intrinsically passive. "Active" pickups are simply passive pickups with buffers built into their shells.

Now _THAT_ is one hell of a first post