Pedal input/output impedance technical question.

[Eric Morgan]

Hello, all.

I was thinking over the weekend about soemthing I read regarding effects order in a chain but they didn't touch on one topic.

Here's what I read (not verbatim):

They said that fuzzes (amogst other effects) work better with a high impedance signal so you shouldn't put any effect with buffered bypass (which according to the article lowers the impedance) before it.  
That also lead me to believe that active pick-ups would yeild the same response.

Now, if I plug a guitar/bass with active pick-ups (EMG's) that inherently have a low impedance output into, say, a wah does the signal coming out of the wah (which is true bypass, by-the-by) become converted to high impedance due to the pedal's circuitry when engaged?

Any thoughts?  Any info is appreciated!

Hope all is well with everyone.  

Eric.

[R.G.]

Hello, all.

I was thinking over the weekend about soemthing I read regarding effects order in a chain but they didn't touch on one topic.

Here's what I read (not verbatim):

Hi, Eric.
The problem with that is that it's not possible to understand what it was that you read. Do you have a reference? "Something I read" is tough to work with.

They said that fuzzes (amogst other effects) work better with a high impedance signal so you shouldn't put any effect with buffered bypass (which according to the article lowers the impedance) before it.  

One reason I said what I did above is that this is a partial truth - less than a half-truth. It is true that *some* fuzzes work better with a high impedance signal, and in specific, the raw input from the guitar's pickups. The ones that do this are the Fuzz Face and its innumerable clones, and perhaps a few other germanium-transistor fuzzes. For most of the other fuzzes in existence, it not only doesn't matter, but the fuzzes themselves include buffers to make the incoming signal be low impedance before they work on it. This last includes the ubiquitous tube screamer and its innumerable clones and mods.

It is possible that the person who wrote the stuff you read either was telling a partial truth to sell something, or that they themselves did not understand the real facts. That's the wonder and the disaster of the internet - anyone can put content up as though it was the truth.

That also lead me to believe that active pick-ups would yeild the same response.

And this is the the correct logical extension of a problematic starting point. If the original item were fully and completely true all the time, then yes, active pickups with a low output impedance would do that.

Now, if I plug a guitar/bass with active pick-ups (EMG's) that inherently have a low impedance output into, say, a wah does the signal coming out of the wah (which is true bypass, by-the-by) become converted to high impedance due to the pedal's circuitry when engaged?

It depends entirely on the wah, which may be anything. The most common wahs have a lower output impedance than a guitar pickup, but higher than a buffer. Some wahs are opamp based or have an output buffer themselves and have a very low output impedance. The details matter in issues like this, making it necessary to understand the details before you can generalize.

Hope all is well with everyone.

And with you.

Please ask more questions about issues I've made confusing.

[Eric Morgan]

Hey, RG.

Thanks for the in-depth reply and info.

I can't remember where I read that quote but it definitely wans't on a sales pitch 'site or anything.  It just got me thinking after I read that.

I was specifically talking about a Little Big Muff Pi and an fairly accurate Octavia clone on bass guitar. 

The LBM didn't really seem to have any "issues" with active or passive pick-ups...it broke up the same.  The wah I am using is a ProTone El Diablo, I shot Dennis an email about the circuitry but haven't heard back yet.  I don't think it's a modded CryBaby as it's in a High-Gain Volume housing so I can't for sure tell you what's in there...only that it's the best wah I've ever owned.

However, my Octavia copy doesn't erupt with the active pick-ups unless I put the wah's pedal completely back (bass side) and even still it takes a while to start revealing the high octave.  When I use passive pick-ups the high octave comes out faster and louder.  Both boxes have a great fuzz with active or passive pick-ups.

I'm just looking to bring out that high octave a bit more, but I already have a plan in motion for that.  Putting a GRO in front of it with a variable null carrier mod.

I'll let you know how it goes.

Thanks, again, for your reply.

Eric.