Magnetic/piezo blend pedal!

[darren]

Years ago, when i first read about electric guitars being equipped with piezo pickups, i was fascinated by the idea of having electric and acoustic sounds on one guitar, and being able to blend between them.

A number of years later, i finally got a Parker Fly Classic, and was finally able to get the sounds i'd been hearing in my head for years. Then i started playing seven string guitars, and i got my amazing Petrucci 7 with the piezo option. But actually using the two sounds in a live context the way i wanted to would have required an extra hand or two to blend seamlessly from one sound to the other, or to add just a bit of magnetic warmth to a clean acoustic sound, as an example.

I started looking around for a stereo blend pedal... one that would allow me to go from 100% magnetic to 100% piezo with both at full volume in the middle of the pedal's travel, while i played, without using my hands... which were obviously occupied with the task of playing! Much to my amazement, nobody made one. At least not that i could find. Fishman made a "PowerBlend" pedal for a while, which was essentially a Morley volume pedal with an acoustic buffer/preamp circuit and a pass-through for the electric signal. It didn't really "blend" at all. (Apologies to Blendtec.)

I emailed just about every company that made volume pedals, including Ernie Ball, even a bunch of boutique pedal makers. Nobody made something that did what i was looking for.

For a while, i used a convoluted workaround of using a stereo expression pedal (a BOSS FV-300L) that allowed me to simultaneously control the volume of my GT-6 and Yamaha AG-Stomp in opposite directions with custom settings that made the volume pedal only work in half of its travel on each device. It was big and kludgy, but it worked. But i wanted something simple. Something passive. Something i could use on its own or in different rig setups.

So i made my own.



I wanted it to be passive, and as simple as possible. I bought an empty wah pedal shell, a 500k blend pot and a 25k blend pot (i wasn't sure which would work best), and a bunch of jacks. I wired it all up and started testing, experimenting, troubleshooting and tweaking.



What you see here is my second prototype. I use a stereo cable coming out of my guitars, and that goes into the right side of the pedal. The signal is split to the two halves of the blend pot, and then output to a pair of mono jacks on the left side. Simple. Effective. It's not pretty, but it works.



(One of my other guitars uses a GraphTech GHOST piezo system, and in the first prototype, i encountered an issue with the stereo/mono detection feature in the GraphTech AcoustiPhonic preamp that makes it work in an undesirable way with a pot placed directly after it in the signal chain. I worked around this issue by placing another active device in the chain before the pot. The "send" and "return" on the top of the pedal are for inserting my Tech21 Acoustic DI before the piezo signal reaches the blend pot.)



In the heel position, i get 100% piezo (or as close as the pot will get me). In the toe position, it's all magnetic. In the middle, there is a very slight detent, which you can just barely feel through your foot, and both signals are at full volume there. With the tension on the treadle set just right, it's a little easier to locate, and you can quickly find it and the pedal will stay there.

This is exactly what i've been looking for. It enables me to blend smoothly and seamlessly from one sound to the other, or to add a bit of one sound to the other, without interrupting my playing.

If anyone is interested in something like this, i am considering building them to order, now that i've worked out some of the kinks. I've tested it with my GraphTech GHOST-equipped guitar and my Music Man JP7 with piezos. I no longer have my Fly Classic, but i remember it had a stereo/mono switch by the jack, so i don't see why it wouldn't work with Parkers, though i don't know how the newer ones are set up. I suspect it should also work with Godins, or other Fishman, L.R. Baggs or RMC-equipped guitars as well. But it works flawlessly with my JP7 running out of the stereo jack.

What are your thoughts? Am i the only one who's pursued something like this? Am i the only one interested in being able to blend hands-free?

[Spudmurphy]

Hi interesting thread.

I'm in work at the moment and can't try out my own EB Stereo Pedal and Piezo EB's, so can you explain to me what your pedal does that the EB Stereo pedal can't?
Cheers
Spud

[dannymusic]

how much?

great to hear such novel treachery.

[darren]

Originally Posted by Spudmurphy

Hi interesting thread.

I'm in work at the moment and can't try out my own EB Stereo Pedal and Piezo EB's, so can you explain to me what your pedal does that the EB Stereo pedal can't?
Cheers
Spud

My understanding of how the EB 500k Stereo Volume/Pan pedal works is that it functions as a stereo volume pedal (allowing you to raise or lower the volume on the A and B channels simultaneously, in parallel) OR it pans input A between output A and B.

My pedal only works as a blend, while maintaining separate signal paths for the magnetic and piezo signals. Think of it as two volume pedals working in opposite directions at the same time, only instead of both channels being at 50% in the middle, both channels are at 100%.

A <--------> A+B <--------> B

But the signals are not being combined at any point... the signal chains remain independent, so the magnetic signal can be sent to a guitar amp and the piezo signal can be processed and sent to a PA, a console or an acoustic amp. Another way of looking at it:

100% mag <--------> 100% mag+piezo <--------> 100% piezo

As far as i know, there is no commercially-available pedal on the market that does this. I think i can also modify one of the outputs so if you ONLY have a mono cable plugged into the magnetic output, you'll get both signals summed to the mono cable, but you can still pan between the inputs using the pedal.

[beej]

Nice work. There are a few different ways to do this, glad it worked out for you. In a blend situation you definitely need both signals to be active.

[darren]

Originally Posted by dannymusic

how much?

great to hear such novel treachery.

Treachery indeed!

Answering "how much" is tough at this point. If i were to build and sell these, it would probably be in the same ballpark as a good volume pedal.

How much would people be willing to pay for a unique pedal such as this?

[darren]

Originally Posted by beej

Nice work. There are a few different ways to do this, glad it worked out for you. In a blend situation you definitely need both signals to be active.

It's definitely tricky, because depending on the preamp design and how the guitar is wired, you may have active piezos and passive magnetics.

In one of my earlier prototypes, i built an EMG PA2 into the pedal (in its "off" mode) to act as a buffer for the magnetic signal, but it wasn't necessary because i believe the GraphTech AcoustiPhonic preamp already buffers the magnetic signal.

Does anyone know if the EBMM piezo preamp buffers the magnetic signal?

I'm currently using a 25kOhm blend pot in this, and it seems to work nicely.

[colinboy]

Impressive work my friend.Im pretty confused about this actually.

For example how does John Petrucci go from his electric magnetic sound to his piezo sound in 'The Spirit Carries' in the live DVD Score?
I thought he just uses a single pan/volume pedal between the two???

[colinboy]

Can you mix the two signals with the guitar itself in the middle position on the toggle for piezo/magnetic?

[darren]

Originally Posted by colinboy

Impressive work my friend.Im pretty confused about this actually.

For example how does John Petrucci go from his electric magnetic sound to his piezo sound in 'The Spirit Carries' in the live DVD Score?
I thought he just uses a single pan/volume pedal between the two???

Having never seen this video, i can't tell you for sure, but keep in mind that Petrucci also has a monster MIDI-controlled rig. There are other ways to achieve this level of control over the magnetic and piezo signals... but a passive blend pedal is the simplest one.

Originally Posted by colinboy

Can you mix the two signals with the guitar itself in the middle position on the toggle for piezo/magnetic?

The switch on the guitar does exactly that. But it's tricky to use while playing, and only gives you the option of all magnetic, all piezo or a blend of the two at the levels set by the volume pots on the guitar. If you want to do a smooth gradual transition from one to the other, or add just a little of one signal to the other, it's a little more tricky to do on the fly. With my pedal, i just leave the switch in the middle position and control the blend with my foot.

I conceived this pedal out of my own personal need... i'm just trying to figure out if there are others out there who might appreciate a similar, simple solution.

[colinboy]

Originally Posted by darren

Having never seen this video, i can't tell you for sure, but keep in mind that Petrucci also has a monster MIDI-controlled rig. There are other ways to achieve this level of control over the magnetic and piezo signals... but a passive blend pedal is the simplest one.



The switch on the guitar does exactly that. But it's tricky to use while playing, and only gives you the option of all magnetic, all piezo or a blend of the two at the levels set by the volume pots on the guitar. If you want to do a smooth gradual transition from one to the other, or add just a little of one signal to the other, it's a little more tricky to do on the fly. With my pedal, i just leave the switch in the middle position and control the blend with my foot.

I conceived this pedal out of my own personal need... i'm just trying to figure out if there are others out there who might appreciate a similar, simple solution.

Cheers for the advice mate.
As far as i know JP uses a stereo pan pedal to switch between the two.In the song i mentioned above he switches from his distorted magnetic guitar sound to his acoustic sound very quickly for the first part of the song.
Was just wondering how it was done as i want to have this option added to my rig

[Slingy]

There is a forum member who here who uses a PodX3L to do this. Not sure exactly, but it has two mono inputs with seperate signal chains and configureable outputs, stereo, completely seperate, or summed.

[Spudmurphy]

I'm still a bit confused - sorry I am thick at times!!

I have done a demo of my Stereo pedal using my JP my AER Acoustic amp and my Mesa.

It's uploading to you tube at the mo via my steam driven computer - watch this space !!

Edit
here it is filmed in fading light. If you want me to highlight any feature of the pedal I'll have another go.

YouTube - Ernie Ball 6165 Stereo Pedal demo for EB Forum

YouTube - Ernie Ball 6165 Stereo Pedal demo for EB Forum

[darren]

Spud: Having never used an EB stereo volume/pan pedal, i have no idea whether it does what i need it to do, and i didn't like the idea of spending $170+ to find out. I'm looking forward to your video demo.

From the description on the EB site (and the FAQ), it's unclear as to whether their pedal does the "100% of both signals in the middle position" or whether it's a straight crossfade from 100% to zero on each channel (in opposite directions) which gives you both channels at 50% volume in the middle. Both signals at 100% in the middle of the pedal's travel is the primary goal i've been trying to achieve.

Starting in the middle position, both signals are at 100% volume. Push the pedal toward the toe and it turns the piezo down to zero so you're left with 100% magnetic sound. Pull the pedal from the middle position back toward the heel, and the magnetic signal is turned down to zero, giving you 100% piezo sound. And of course, you can blend the signals anywhere in between.

There are lots of ways to achieve the same result. You can do it with the X3L by using its effects return as a second input and the X3's "dual amp" mode to process the two signals separately.

I used to use a stereo expression pedal to independently control both my GT-6 and a Yamaha AG-Stomp to achieve the same thing. (I also could have done this via MIDI.)

The beauty of a passive, standalone pedal is you can use it with your own gear, or even simple setups where you're plugging straight into the amp. That's why i designed this.

[darren]

Just watched the video... nice demo! But the still-unanswered question is, "What happens in the middle of the pedal's travel?"

It appears to me, from your demo and a Blues Saraceno demo i also just watched, that the volume swell/cut happens over the pedal's full travel, and that in the middle, neither signal is at 100% volume.

It's *almost* what i would want it to do, but not quite, which at least gives me some validation that i haven't re-invented the wheel.