For as long as there have been electric guitars, there has been feedback. Even solid body electric guitars with electromagnetic pickups will feed back if the volume is high enough.
So to build hollow body amplified guitars that will resist feedback has always been a challenge.
My Super ACE and Super Steel designs deploy special features that I am using to resist feedback. Guitar makers who eliminate the sound hole do so to prevent the body cavity resonance from being cycled from the amplifier back through the pickups causing feedback to occur. My guitars do not easily cycle body cavity resonance. The body cavity is a large component of an acoustic guitar's sound, negated if the sound hole is eliminated.
As of the fall of 2015 I am offering pickups made by Graphtech Labs. These are individual saddles for ultimate string separation. I have designed a preamp of my own to serve my needs for the pickups to have great tone and feedback resistance. The McGill Preamp uses phase inversion to cancel frequencies from being reamplified from one string to the next. When used with separate pickups keeping the minimum of frequencies cross over between strings much of the problem is eliminated. I have found this is the best way to resolve the issue of feedback. Frequencies cancel each other out rather than cycle into feedback.
In other words, you can play a note on the high E string while playing the same note on the B string and there will be no feedback, even at very high volume. The two notes are the same frequency in opposite phase which eliminates feedback. Getting rid of the sound hole will not do this and is not the best solution to body cavity feedback issues in my opinion.
Other guitars, even with phase inverted pickups, feed back, while mine do not. Feedback is also inherent in the structural integration of the guitar. The proof is exposing a guitar to high amplitude ambient vibrations to see how well it resists cycling those frequencies.
To make a guitar that is a great sounding acoustic as well as a great sounding amplified instrument requires more than simply closing off a sound hole or investigating which pickup system is the latest greatest thing.
There are greater issues in the interaction between structure and electronics to achieve an ultimate sound without either compromising the acoustic sound or making the amplified sound uncontrollable.
On this website you can see examples of guitars being featured both unplugged and plugged in. I did this intentionally to demonstrate just how well the designs work in both applications.
In the Peter White videos, you will see him standing right in front of drummer Eric Valentine who is not holding back. This is a loud environment on stage with much volume to overcome. A blaring saxophone is having no effect on the guitar feeding back. Peter even uses a fuzz box on occasion. I include a studio recording of Marc Antoine followed by a live performance of Marc on the same Super Ace on stage with Marc's band.
Guitars can be truly acoustic and not feed back
uncontrollably amplified, even when stressed on stage at performance volumes.