why? what is the purpose of the buffer switch? What is the benifit of engaging the buffer switch rather then true?

The guys at EHX really did their homework, as usual.

The Soul Food pedal is essentially EHX’ Klon Centaur clone. There are many Centaur clones, but I think EHX’ is the best.

The Centaur had many unique features. The Centaur circuit is very different from anything else being done at the time. The main goal of the original circuit seems to be the ability to blend in some of the clean signal with some of the overdriven signal to preserve transparency and to make it play nice with an amp’s front end.

Another very important feature was a voltage converter that drove the op amps at 18 volts. This changes their response to dynamics.

The Centaur had buffered bypass and this was not selectable. This seems to be a side effect or byproduct of the way the circuit is designed to always blend in some of the clean signal. Many users of the original Centaur report that they like the sound of the Centaur when engaged, but HATE what it does to the sound when bypassed.

So, that brings us to the Soul Food. The Soul Food simulates the Centaur circuit VERY closely. One notable difference is that the original circuit used germanium diodes and the Soul Food uses silicon diodes. I’ve seen a very detailed Soul Food mod that allows you to switch between germanium and silicon and in the end the author writes that the difference in tone is EXTREMELY subtle and probably not worth the effort.

The Soul Food also uses a voltage converter and runs the op amps at 18 volts. So, we’re good there.

That leaves your original question. What’s the benefit of a buffer? Why make it switchable? EHX was making a Centaur clone. One of the features of the Centaur was a buffered bypass. Some people LIKE what it does to their signal chain. That’s most likely because of the way buffers interacted with vintage effects. Some vintage wah or volume pedals interacted horribly with distortions placed after them and required a buffer. So, if you’re a “distortion after the wah” kind of guy and you’re using a vintage wah circuit, you might actually NEED a buffer between the wah and the distortion.

EHX realized that many people don’t need and/or want that now because of modern pedal designs, so they made it switchable in their pedal. This might actually make the EHX a better Centaur than the Klon for many people. Add to that the fact that you can buy a new EHX Soul Food for about 1/25th of what you might pay for an original Klon Centaur and you have quite a deal.