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Pedal Myths


gardo

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True bypass is true except pedals are basically lo fi deals where if you chain enough of them or have long runs to and from, you'd be better off with buffered. For me it has an aesthetic to it that since most of my pedals are or have been unbuffered, I stereotype into the plus column.

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I give an B+ on that video covering many of the myths. There are many other's he missed but the ones he did hit were pretty good. What he did miss is surface mount parts are typically not repairable, at least not by most hobbyists using a soldering iron. I might have tried it back when I was in my prime and had steadier hands and better eyes, but the traces are so darn small you really need the kind of microscopic soldering stations factories use to get that done right.

 

As far as the True Bypass argument goes, most people including that guy apparently don't know how that myth got going. It had nothing to do with True bypass vs buffered pedals in the beginning. That all came much later so I'm guessing that guy either didn't know his pedal circuitry history very well or he simply didn't want to baffle people with all the possible bypass switching possibilities.

 

Many early pedals used a variety of bypassing options. Some used true bypass which completely disconnected the circuit from the signal path and sent the signal through the pedal as though it contained a straight wire.

 

Depending on the pedal type, switch used, the bypass could leave circuitry connected which loads the signal down and sucks tone and volume. One that immediately comes to mind are the older Dunlop Wah pedals.

 

This diagram shows one of many switch variations which were used in older pedals. The reason for this is typically cost savings. A single pole double throw switch is about half the cost of a double pole, double throw or even much less then a 3 pole switch often used in pedals that have on/off LED's

 

If you trace this circuit the input signal splits, it goes directly to the switch and it goes to the circuit where and input resistor connects between the input signal and ground.

 

Back at the switch in the down (red) position, the circuit output is disconnected and the input jack is connected to the output jack.

Problem is the circuit input is left connected and that input resistor leaks the signal to ground which lowers the pickup volume and probably sucks tone too, just like a potentiometer does when it's turned down.

 

 

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Here's an example of the above in both modes, on and bypassed.

 

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Here's how a double pole switch bypasses the circuit. both the input and output are disconnected from the circuit and pass with a straight through.

 

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As the man said, buffered pedals simply keep a 1:1 amplifier in series instead of bypassing the signal completely. Given the fact a transistor cost pennies and a true bypass switch can cost up to $10 its mainly a profit decision. you can use a simple momentary push button mounted on a pcb that cost a penny and use a couple of transistors in a latching circuit to switch the effect part of the circuit off. Overall the pedal when connected can have a greater then 1:1 boost like many boss pedals do. Both the effected and bypassed levels are greater then when the pedal is true bypassed.

 

This can actually benefit a pedal board when all your other pedals are passive bypass because the buffering helps boost the signal to overcome resistance losses long cables, multiple connectors and multiple switches produce. When you switch a bypass switch the contacts are only pressing against each other. Over time, dirt, lubricants combined with metal particles, Oxidation and carbonization caused by small electrical sparks, plus the metal being worn uneven and having less contact area between the poles can cause the switch to conduct less and the powdered metal particles can eventually short the switch. Of course cleaners can sometimes revive them, but replacement of a 3PDT switch compared to a momentary pushbutton can be quite expensive.

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