Are any MXR pedals true bypass ?

[Liberty Belle]

Crafty indeed!

[woodsmandan]

 

I was reading reviews for the Dyna Comp here on HC, and one reviewer mentioned that the latest model (serial starting with AB...) was true bypass...any truth in that ?

 

 

So...the short answer is no...I guess...

[andreas]

Lots of confusion here... let me add some more

 

fix'd

I'm not sure if this was done as a joke or not, but I'll use it anyway, in the interest of public awareness...

 

Many people are under the impression that anything that isn't true bypass is - by default - buffered. The reality is very different. A buffered system has at least one active buffer stage in the signal path at all times, and although it doesn't have to have electronic (Boss-style) switching, most of them do. The "hardwire" system is neither buffered nor true bypass - in fact, it's got the worst of both worlds. If there had been only buffered or TB systems, things would have been much better. Both are good in their own way, and neither will cut into the signal the way the "hardwire" system does.

 

As always, sticking a buffered pedal in front of the one with "hardwire" bypass does diminish the tone loss. In many cases, we do that without thinking about it (which is why some claim the MXR bypass is just fine, while others can't stand it - it depends on where in the chain the MXR sits).

 

Now, here's what a "hardwire" system looks like:

 

 

Note how the signal is free to pass straight through the pedal (in either direction), with or without power to the circuit. Also note the fact that the circuit is permanently connected ("hardwired") to the input jack, which is what is causing the signal loss.

 

For comparison, here's how a true bypass wiring looks:

 

 

This time, the circuit is disconnected from the bypass line, stopping any signal loading.

 

There are several ways to wire for TB, but all of them have the same basic prerequisite: in bypass mode, the circuit is disconnected from the bypass line at both input and output. If you also want to have an LED there are more possibilities. Many will simpy use a bigger switch (a 3PDT) to allow switching the LED on/off as well as the signal. You can also use the output impedance of the effects circuit to control a transistor which in turn controls the LED (Millennium bypass). As the effects circuit is not in contact with anything else in bypass mode, it can be used for the LED switching without breaking the basic true bypass rule.

 

So... to the Carbon Copy. I haven't opened one up, but I too read the post from Jeorge Tripps (the designer) about it. If he says it's TB, it is. And as the CC has a DPDT switch, it must have some variation of the Millennium LED circuit. The diagram posted by WWW looks just like the switching portion used for true bypass with Millennium LED, so it's probably correct. Like Ned Flanders said, the fact that Dunlop isn't boasting about it is probably a marketing thing - they've already claimed their "hardwire" system to be awesome, so they can't introduce a better system without making the others look inferior...

 

I haven't looked into the other new MXR pedals (GT-OD, CAE Boost etc), so I can't say wether they also use Millennium bypass or if they're still "hardwire", but to figure that out, one would have to open them up and trace the circuit. Or just use your ears - if you hear a tone loss, you do. And if you don't, you don't

 

/Andreas

[Dr Wanker]

I have an MXR EVH Phase 90 and EVH Flanger and love the sound of them when they're on, but can't bear what they do to my tone when they're off. It kills me that in the 21st Century we still have to deal with tone sucking.

[hide]

Or just use your ears - if you hear a tone loss, you do. And if you don't, you don't /Andreas

 

Your explanation makes it all so easy to understand. Ultimately, I very much agree with you on the last part that "if you hear a tone loss, you do. And if you don't, you don't"

 

I don't hear a tone loss on the Carbon Copy, I have yet to try any other MXR pedals.