Piezo impedance in the FM9?

macfly

macfly

Inspired
I have put piezo bridges on a couple of my guitars, with no preamp. I don't want to deal with the batteries. So I set up a Tube Pre and use an IR like the "images" in Fishman Aura pedals...in fact one is a tone match of an Aura image. I have to really crank things in the Tube Pre and IR, and the result is pretty good, but I wonder, if the input impedance matched, would it sound better? So my question: can piezo impedance be added to these FAS modelers?

To clarify, I hit a push/push switch on the guitar to switch to the piezo bridge pickup and simultaneously switch to the scene with Tube Pre and IR. Works pretty well! Sure beats switching to an acoustic and having to have a separate rig and input!
 
I knew someone would suggest something obvious that I should have considered, but that's why I'm here, and I do appreciate it! I guess I just got used to cranking those two blocks and didn't even think about that.

Now, is that the same as having a setting in the input block for 10M?
 
That's limited by the hardware. Max input impedance for current Fractal gear is 1M ohm. If you need higher than that, you'll have to use a separate preamp.
 
macfly said:
I knew someone would suggest something obvious that I should have considered, but that's why I'm here, and I do appreciate it! I guess I just got used to cranking those two blocks and didn't even think about that.

Now, is that the same as having a setting in the input block for 10M?
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No, it's not... Just a way to compensate for lower input level.
 
mr_fender said:
That's limited by the hardware. Max input impedance for current Fractal gear is 1M ohm. If you need higher than that, you'll have to use a separate preamp.
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Yeah, so when I do acoustic gigs, I'm using an Aura Spectrum for the regular acoustic and an Aura Jerry Douglas for the resonator. The idea in the original post is for the full band, where there's only one song I play acoustic on. It works well enough that I'm not getting into an onboard or other preamp, but as mentioned, I feel like it could be better---thus the question, wondering if FAS could add 10M to the input impedance choices. What I hear you saying is that it would require an upgrade to the hardware--not something that could happen in software.
 
AFAIK 1MOhm is good enough for passive piezos. That's what passive NSDesign instruments require.
 
GiRa said:
AFAIK 1MOhm is good enough for passive piezos. That's what passive NSDesign instruments require.
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Well, good enough depends on what you find acceptable. My graphtech saddles at 1M have a significant low end roll-off compared to 10M (that's right, piezo pickups behaviour to impedance mismatch is backwards, they lose bass instead of treble).
To solve the problem I made a little 10M buffer and put it inside my guitar, it needs very little current and a 9v battery lasts several months.
 
DLC86 said:
Well, good enough depends on what you find acceptable. My graphtech saddles at 1M have a significant low end roll-off compared to 10M (that's right, piezo pickups behaviour to impedance mismatch is backwards, they lose bass instead of treble).
To solve the problem I made a little 10M buffer and put it inside my guitar, it needs very little current and a 9v battery lasts several months.
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I was about to ask if the OP had enough room in his guitar for that mod.
Can you share the circuit design?
 
Patzag said:
Thank you.
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As I get home I can also share the pcb layout I made out of this schematic. And I should have some spare PCBs of this somewhere, if I find them and if anyone's interested I can give them away for free, you'll just pay the shipping (EU only, the cost for overseas shipping wouldn't probably be worth it)
 
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