Watch the Bypass online guitar lesson by Jeff McErlain from Guitar Effects Survival Guide
Many old school pedal's designs are not true bypass, this means that even when the pedal is disengaged the guitar’s signal still gets sent through some or all of the unit's circuitry. This can load down the guitar signal and cause a little or quite a bit of tone loss and can be very noticeable and very annoying. The truth of the matter is that everything between a guitar and an amp can load down the signal and cause tonal loss, this includes cables. The less cable and pedals in line, the better for a clean strong signal. Try it yourself, plug in your pedals and play for a bit. Then plug your guitar straight into the amp with the shortest cable you can find. I am sure you will hear a difference, more highs and more volume usually. A true bypass pedal bypasses its internal circuitry entirely when disengaged. The benefit of this design is that you don’t get the tone loss you might with a non-true bypass pedal. This way your signal chain is not as weighed down and you get a purer guitar tone. There is a debate among many pedal designers as to which is better, a well-designed non-true bypass pedal with a good line buffer built in vs. true bypass. What is a line buffer? A simple definition is it is a circuit that works to reamplify your signal to its original form. Not all line buffers are created equal, some are better than others. If you use boss pedals for example, they are not true bypass and use a buffer. I think they sound great! I do recommend a separate line buffer if you are using long cable lengths, this will make a considerable difference in your tone. Guitar pedal legend Pete Cornish who has designed pedal boards for David Gilmour, Jimmy Page, Brian May, and most of all the British rock royalty swears by a high quality buffer in pedals. To me, if you don’t hear a difference, don’t worry about it, if you do check into a line buffer unit. They are fairly inexpensive, I use one when using a lot of cable length as do most professionals.