I know its a fairly preferential question, but I a, curious as to whether I would be better off with a guitar with a Piezo system (A P22 or a JP sig with a Piezo for example), or if I would be better getting an acoustic and an electric.

There'd be more versatility with 2 guitars, but having to only use one guitar would be nice too. A Piezo equipped guitar and Axe-FX sounds pretty sexy.

This post may contain my opinion and/or inaccurate information.

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It depends on the piezo (or equivalent; not all acoustic-sounding pickups on electric guitars are piezo pickups) system in question. Some do a fantastic job of replicating an acoustic tone, but those tend to not balance well with the regular pickups, or they rely on body styles that make the normal electric sound not as good. Others don't do the acoustic sound so well, but they fit in better with the normal electric sound and are useful for blending.

Additionally, a lot of their use will depend on how you're running them. If you can get two jacks and have the piezo go to its own acoustic amp then that will make the acoustic sound a whole lot better, but it's not always convenient to have two cables coming from the guitar, and on some guitars just fitting two jacks is a huge problem.

If what you want is a dedicated, strong acoustic tone to use for a whole song then you're best off buying a good acoustic and switching between the two guitars. Even the very best piezo system through the best acoustic amp is not going to sound 100% like a real acoustic, so if that's your goal then don't bother with the piezo. If you simply want a tone that's 'good enough' for the occasional verse or intro or whatever, most good quality systems (e.g. fishman, graph tech, shadow) through a totally clean regular electric guitar amp will do that and that will probably be your best option.

Just think very carefully about how you'd use it, how you like your controls laid out, how you like to use your amps and ho much you'd really use it.
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It won't sound like an acoustic guitar. It just sounds different from the traditional pickups. I prefer Piezo pickup on electric for playing clean stuffs instead of the clean from the other pickups.

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Depends on the piezo, really. I think the JP models have a Fishman system which, to my ears, sounds really great. I have an Ibanez RG2120X which has an LR Baggs system. It still sounds good, but I prefer the JP's tone.

As others have mentioned, it also depends on how you're amplifying the piezo output. Since piezo systems use a pre-amp in the guitar (similar to how active pickups like EMG and Blackouts work), running it into another pre-amp (straight into an electric guitar amp) isn't ideal. Acoustic amps are good, but people usually prefer to run straight into the PA/whatever sound system is being used. That bypasses another pre-amp and just gets run to a power amplifier, which is what an electric guitar amp has after its pre-amp.
I've found that most piezos with a preamp can recreate the sound of an aoustic, but the sound is still colder. Also, you wont have the dynamics of playing a true acoustic. I love the sound of a piezo, but they can't emulate the sound of a good ol' acoustic:it doesnt have the same soul. Plus, you can't play a piezo around a campfire.
actually a piezo system and a cheap bass or keyboard amp works really well.

def sounds like an acoustic to me.
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The (China) Peavey I have has active H/H and piezo's under the bridge. With three-way selector (H's/mix/piezo) and independent volumes, I can get an unlimited variety of tones. While the on-board amp supposed emulates a D-28, it still sounds a little "electric"; prolly due to string selection??

Running it thru the Acoustic B-50 amp I picked up sounds brighter over all than when it goes thru the Fender 65r on the pre-amp'd, "hi-gain" channel (#2) . Some guitars (mine, too) with piezo option have a stereo jack to split the PU's. I have yet to do this; but it would add another set of variables and compound the available "tone".

A high quality piezo such as those found in PRS or EBMM guitar, when run through a decent acoustic amp or PA sounds better than many electro acoustics.

You just have to be aware of how bright they can sound thanks to their residing within the bridge saddles usually.

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