Powering guitar electronics

[e100]

As far as I can tell the current defacto standard is the disposable PP3 alkaline 9v battery, which seems like a terrible solution given the myriad of choices available today.

My guitar will forever be connected by a cable (coax or 3 core micropone because it's physically robust) so having an onboard battery doesn't make sense.
Is phantom power using transformers still the best way of getting power in and audio out.
What about a current loop, or using inductive charging to a supercapacitor or something like that when the guitar is sitting in it's stand overnight.?
What would you use?

[John B]

For external power, what I have been wanting to experiment with is building a DI box directly into the instrument. I generally use 48V phantom power capable equipment anyways, but it would be a hassle if you need to plug the instrument into a regular amp.

Plus you get to use XLR instead of 6.5mm TS jacks which are really only good for infrequently plugging/unplugging. I've used some decent quality, fairly expensive jacks like switchcraft I think, and they still don't last as long as basic XLR jacks.

[Buriedcode]

When you say "guitar electronics" are you talking about active pickups? Or on board effects? I guess it doesn't make much of a difference.

I believe there are active pickup systems that use AA's, but I can't remember the brand right now.

Years ago I built an FET buffer inside a mono jack (guitar end), that used standard guitar cable, that had to be plugged into the battery box that provided power to the signal line, and the audio came off that via a capacitor.  But since your active electronics are already on board, 3 core cable would do, with a stereo socket on the guitar.

That would need a custom box to plug into, that contains either a 9V battery, a socket for external DC power (preferably with a filter included, because nothing is as quiet as a battery), or maybe even a different battery and boost converter (which should probably be low noise).

The downsides of the above are - you need to change the socket on your guitar from mono to stereo.  It needs an external "box" to work, you can't just plug a standard cable into it, and your amp and go.
And it'll increase the cable length, since you'll have your stereo cable from your guiatr to the box, then from that box standard cable to the pedalboard/amp.  If you're using active pickups, this probably isn't much of a problem since it'll be low impedance enough to not really be affected by long cable runs.

The advantages are: Easily available parts, just a stereo cable, two sockets, and a box.  And of course the stereo socket for your guitar.

Actually, as you need to use a stereo socket on your guitar, keep the tip the signal, but make the ring power input to the on-board electronics via a power path circuit.  That way, when a mono cable (standard) is plugged in, it'll run off the on board battery.  But if a stereo cable is plugged in that provides voltage similar to that of the battery, the electronics will run off that and not drain the battery, so you can still use the original way.  It's more work, and requires a "circuit" to be added to your guitar, but its pretty simple.

I too hate 9V batteries.  They are expensive, and often don't have particularly good capacity, but their small size and higher voltage means they're still very common in guitar gear.  Often active pickup circuits are very low power, so they tend to last a long time too (just as well).

edit: about 40 typos.

edit:
Just realised they use setereo sockets already to turn-on the on board electornics - a mono jack will ground the ring connection.  This may require something a bit smarter that my above idea.

edit #3: If you have active pickups, you'll have the stereo socket installed already. Removing the battery and shorting the contacts on the battery clip will connect Vbatt+ to the ring, meaning you only
              need a stereo cable, and a power supply to power the ring of the stereo plug.