Buffered vs. True bypass

Wizard

I'm sure this has been covered; but can't find a concise answer.

I understand that "true" bypass in a pedal effectively is a hard wiring through the pedal; so acts as if there were no pedal (other than the cable length).
I think that I understand a buffer to be an impedance changer. Not sure if I'm correct here.

I have seen people on the forum speak about "true bypass" with a somewhat religious fervour as if a buffer were a virus that needs to be surgically removed.

I have also though seen someone build a separate box to act as a buffer.

What are the practical guidelines regarding whether pedals should have buffers or true bypass?
If one were always better than the other, then we know that all pedals would use this ideal.
So it must be more interesting than that.

MikeM

Wahs, fuzzes and buffers don't mix (there are exceptions).

Otherwise a good quality buffer is actually good for tone - not sure if you've heard the difference between a short and long cable? A buffer can make a long cable react like a short one.

They can also reduce dynamics from what I understand, but with a high quality buffer this is not an issue.

I think it's good to differentiate between bypass, buffered output and true bypass. Regular bypass is crap, think old school pedals and wahs etc. But buffered and true bypass are much of a muchness.

In terms of wahs and fuzzes, they are very sensitive to input impedance. This can be a lovely thing, as you turn your volume control down, the impedance changes (I think?) and with this the tone changes. However if you put a pedal in front of it, it responds entirely different, usually waith less dynamics. Sometimes it can actually sound better, Mika and I fiddled around with buffers on his pedalboard and actually found that his setup sounded better with a buffer into the fuzz.

So above all, remember that music is an art, not science. Our ears perceive things that can't be measured, so it's worth trying out all the options you have.

rikus

Have a look at these articles. They made the buffer/bypass/impedence thing a bit clearer for me.

http://www.muzique.com/lab/truebypass.htm

http://www.muzique.com/lab/imp.htm

greetings

You get good buffers that sound great and cheap buffers that sound terrible. A large pedalboard of only true bypass pedals will have tone loss if you aren't using a switching system. It's a good idea to have mostly true bypass pedals, along with one or two pedals with really good buffers. One buffer near the beginning of the chain to buffer the signal through the pedalboard, and possibly another near the end of the chain to buffer the signal through to the amp, but this one is not always necessary.

I have a buffered pedal at the beginning of my chain and the rest are true bypass, and then another pedal with switchable true/buffered bypass that I change depending on the sound I'm going for. Very happy with this setup.

AlanRatcliffe

Frodo Baggins wrote You get good buffers that sound great and cheap buffers that sound terrible. A large pedalboard of only true bypass pedals will have tone loss if you aren't using a switching system. It's a good idea to have mostly true bypass pedals, along with one or two pedals with really good buffers. One buffer near the beginning of the chain to buffer the signal through the pedalboard, and possibly another near the end of the chain to buffer the signal through to the amp, but this one is not always necessary.

^ This. That sums it up nicely.

Time based pedals like delays and reverbs also work better with buffered circuits as it allows for the delay/reverb sound to taper off naturally when the effect is turned off. A true-bypass reverb would cut the reverb sound the moment the pedal is bypassed, which sounds quite odd.

Pierre-Cronje

Wizard wrote I'm sure this has been covered; but can't find a concise answer.

I understand that "true" bypass in a pedal effectively is a hard wiring through the pedal; so acts as if there were no pedal (other than the cable length).
I think that I understand a buffer to be an impedance changer. Not sure if I'm correct here.

I have seen people on the forum speak about "true bypass" with a somewhat religious fervour as if a buffer were a virus that needs to be surgically removed.

I have also though seen someone build a separate box to act as a buffer.

What are the practical guidelines regarding whether pedals should have buffers or true bypass?
If one were always better than the other, then we know that all pedals would use this ideal.
So it must be more interesting than that.

Allow me to add my penny's worth on this one!

A buffered bypass is more cost effective than a true bypass and is done via an electronic circuit or op amp. This can allow for silent switching. Depending on the design it could have no effect on the tone when a couple of pedals are used in series. Some of them affect the tone quite badly when in a series arrangement.

A "true"bypass either routes the wires via the foot switch or via a miniature relay with the former being more common due to cost. In "true" bypass it is also quite possible to get a "thump" through the speakers when switching the effect in. Personally, being from the old engineering school of thought, I prefer the miniature relay system. I have managed to string together 7 Boss pedals and a Morley Wah in series with a self developed miniature relay circuit and there is no tone/frequency change when the pedals are all out of circuit. (Boss pedals are notorious for changing your tone when a couple are in series and switch off). The only thing with bypass is that an extra (very small) circuit may be required to remove the "thump" if it is present.

In conclusion, one is not really better than the other.

Wizard

What is the best circuit to build for a stand-alone buffer pedal?

Danny-B

The Klon buffer gets a good rep.

Wizard

Danny B wrote The Klon buffer gets a good rep.

Buillt this buffer based on the Klon.
It doesn't work. ☹
Computer programs are easier to debug.
* grump *

rikus

Did you build it from a verified vero layout or did you use a diagram and did the vero layout yourself? Maybe post the diagram/vero layout.

Wizard

Here's the circuit:

And here's the layout I used.
Including the note about the error!
(which I fixed after this pic was taken - but still didn't work)

http://147pedals.blogspot.com/2010/11/plon-fentaur-buffer.html

Matt gave me a different layout to try, which I rejected because the parts were too closely located.
I shall pay heavily for ignoring the guru-ness of Matt!

rikus

I built a different buffer from another (similar) circuit and I made that same mistake (pin 5 of the opamp to ground) :-[

Have you tried a different IC? Last thing I can think of, have you checked the tracks on the bottom with your multimeter (that the breaks in the tracks are broken en no shorts between tracks)?