• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

Calling Bongo - Testing True Bypass - Multimeter?

excane

Inactive
Aug 23, 2005
3,857
14
New York, NY
So in my endless tinkerings with true bypass, I was wondering can you easily test a pedal to see if it's legitimately TB or not?

Can you use a Radio Shack multimeter such as this?

Invalid Link Removed

In theory, the input impedance should be the same as the output? Yes?.... No?..... I'm an idiot? (well most likely but that's a different story)
 
No, you can't test it properly with a multimeter, and no, it has nothing to do with input/output impedances. Plus, you can't measure input, and especially, output impedances accurately with a multimeter.

There is one way to definitively test for proper true bypass - and that is to open it up and trace out the switching circuit.

Many claim that measuring for continuity from output to input (and vice versa) demonstrates true bypass, but they are wrong. This cannot tell you whether or not the input of the circuitry remains connected whilst in bypass mode.
 
I've often thought about (someday, when I'm competent) developing a mini spectrum analyzer and pink noise generator, a little iPod-sized device with 1/4" balanced/unbalanced input and output jacks. Something where the layperson can quickly and easily test signal alterations. Really the only difficult part is a legible and meaningful readout screen.
 
Again, as was clarified in the other current thread on this subject ;), just because a signal passes from jack to jack in any order with no power applied, does not mean that when power is applied the signal doesn't flow through some or all of the effect circuit.
 
It really doesn't work that way either. Seriously, stop obsessing about True Bypass. It makes no difference!

I think that "It makes no difference!" is an overstatement, but Toasted is absolutely right that there is no reason to obsess over true bypass. Unless that's how you get your kicks, which is kinds sad! ;)
 
excane, have you read through the true-bypass stinkfoot articles? All of your tb questions are most likely answered there by a knowledgeable engineer who keeps it simple!

Again, scroll down halfway to "True bypass stuff":
http://www.stinkfoot.se/andreas/diy/diyhome.htm

well SOME kind of non-buffered bypass IS preferable in a fuzz-to-filters loop, for instance. But you have to come to grips with the concept first...
 

Latest posts