It's all in the words...

[Ge_Whiz]

Congratulations to Ovation for doing the impossible! Their 'Applause' model AE28 "electro-acoustic" comes with a PASSIVE "preamp" offering "gain" and tone controls. No batteries needed! Once fitted with one of those elasticated "weight-reducing" guitar straps, all you need is one of my "active" plectrums - $29.99 on e-Bay.

I'm off to the workshop now to build a passive booster.  

[Nasse]

:?:  :shock:  :?:

Is it

a) They invented the Perpetuum Mobile

b) It takes its power from signal by rectifying it, or can you just pick up mains hum and radio stations and power it with these

c) It really is passive

[Ge_Whiz]

It really is passive. They have just redefined the words "gain" and "preamp" to mean "loss" and "little plastic box with sliders" respectively.

[Nasse]

I forgot to mention solar power

There were not such guitars around when I was young. I think young customers are used to that there is such knobs and controls in your acoustic that design engineers made obvious choice. Maybe the planet will survive.