More recently, he's been using a Baggs pickup in his stage guitar (a cedar-top Olson), with a Chard Stuff preamp, a Yamaha SPX-90 effects unit, and an external mic.
For a long time he used a more complicated setup, centered on the three-transducer system he had in his Olson guitar (he has since updated his Olson setup to be similar to his Langejans setup). Here are two fairly recent descriptions of this older setup. The first is closest to the setup he uses in his Acoustic Guitar Style video, although for the video he also used an external microphone. Phil discussed the pros and cons of the Olson and Langejans setups in the Spring 1996 PKC (Phil Keaggy Club Newsletter). You can learn more at the Way Back Home Keaggy Web Site.
From "Out of the Mainstream" AG May/Jun 1992 (Dave Urbanski): "Phil Keaggy plays two cutaway acoustic guitars handcrafted by James Olson... he also plays a Takamine classical guitar.... For guitar amplification, Keaggy blends the output from a Sunrise soundhole pickup, an L.R. Bags saddle transducer, and a Fender M-1 internal microphone. To get his signature sound, he has a fairly large rack that contains an O'Neal Custom Equalizer, an Alesis Quadraverb, a DBX compression unit, a Roland SDE-3000 Digital Delay, a Furman PL-8 Power Conditioner and Light Module, a TC 1210 Spatial Expander and Stereo Chorus/Flanger, and a Carver Professional PM-300 Magnetic Field Power Amplifier." He uses the latter to power stereo monitors.
From "Phil Keaggy Tried and True" FG #4, 1994 (John Schroeter): Keaggy's guitars are outfitted with a Sunrise soundhole pickup, an L.R. Baggs under the bridge, and a Fender M1 internal condenser microphone. Greg Gualteri, of Pendulum Audio, built for Keaggy a custom preamp for combining the three signals. From time to time, Keaggy uses effects, such as an SDE3000 Roland digital delay, for getting into the "playmate" mode, locking in a particular rhythmic pattern and playing around it.
Phil briefly described the evolution of his setup as follows; from "Phil Keaggy: The Master and The Musician" GP June 1995 (Matt Resnicoff): Around '84 James Olson built me a guitar with a cedar top that I used for years. I also came across a phenomenal Langejans cutaway with an L. R. Baggs Duet system---a Baggs pickup and mike, which you can blend. I had a complicated setup with the Olson, with a five-pin cannon going in connecting a Sunrise, a Baggs, and a Fender M1 mike. I went through a Bob O'Neill preamp, then a Pendulum stereo preamp. Then I had conflicts blending the Baggs and Sunrise, and a lot of my rack equipment ended up getting damaged on airlines. So I went real simple with the Langejans, which has a built-in Baggs preamp [a Micro Duet?], direct into the Roland [SDE-3000 Delay] and the [Lexicon] Jam Man [looping delay].
More recently, Kottke has been using a Rane AP13 to process his pickup signals (using the AP13 mic channel for the Sunrise signal).
I guess if you were to work only in places with great acoustics, or really small and quiet folk clubs, then a condenser mike works fine, if it's going into a decent quality p.a.. I would say that 90% of the gigs I work are completely unsuitable for any kind of music, let alone miked acoustics, and come with atrociously cruddy p.a.s, so I work with an Ovation, which produces a signal that is flexible enough for me to eq my way out of most of the problems, but which seems to be a much vilified instrument in this 'hood.Adrian further discusses and demonstrates his setup on his instructional video, Beyond Acoustic Guitar.
I wrote a three part piece for an English music magazine (Making Music) six (seven-eight??) years ago, and we put together a book (called What Acoustic) which tried to cover the various options; their up-sides and down-sides. The simplest way to express it I always found to be to think of the guitar as a spectrum -- at one end a simple acoustic, at the other, the electric. In order to achieve some of the volume possibilities offered by the electric, it is necessary to accept a loss of some of the characteristics we all like about the acoustic, so where we end up on that spectrum is dictated by the kind of gigs we want to play, and how we need to use the guitar. I hope you understand the implications of this. My bottom line has always been simple -- I want to communicate, so whatever it takes to do that is what I use. This seems to be too pragmatic for a lot of people, who romanticise the acoustic guitar -- and why not? It is a romantic thing in the sense that it is, historically and currently, a very significant vehicle for many of the disparate ethnic and social elements that go together to make American culture. I guess if you're going to share music with your friends in your kitchen, then the practical choices that I have to make don't concern you, but if you want to go further outside that circle, then immediately you have to defy the dictionary definition of "acoustic" and use some kind of electric or electronic enhancement. At that point you cross the Rubicon, and I believe that to try to draw the line between acoustic and electric further back from there is futile and specious, and that the intellectual dishonesty involved merely hampers progress and narrows the whole guitar musically.
What you use to record is likely to reflect similiar considerations to your live solutions, but will include budget -- e.g. can you afford soundproofing for mikes or is it simpler just to plug a pick-up straight in; can you afford a Neumann or two, or a 460 series AKG and the cats-cradle mounts for them? has your mixer got phantom power ? And so on it goes...
I always thought that if you asked six guitarists, you'd get ten different opinions.
For stage work, I frequently play an [Ithaca Guitar Works] Oneida guitar, equipped with a Highlander and an internal mic. It's a small-bodied guitar, which is great for playing while standing. Played through a PA head and a Daedalus speaker cabinet, it has great tone, an it's loud!
[Reader Josh Pincus reports from a conversation with Martin after a concert that Martin partly attributes the success of his Highlander sound to the fact that he uses very heavy unwound strings; his first string is a 0.015!]
More recently (fall, 1995), David's Internet fans report that he is using the Baggs pickup in combination with a Sunrise rather than the Acoustech; the two are processed with a Pendulum stereo preamp.