John S. Allen

31ET Acoustic

Didier Aschour

Just Intonation acoustic: 1/1, 13/12, 8/7, 26/21, 55/42, 39/28, 3/2, 34/21, 12/7, 13/7.

John Catler - Freenote Music

36ET electric. This site features a variety of guitars in other tunings, including the 12-tone Ultra Plus, for sale here.

David C. Canright

A just intonation acoustic.

Tolgahan Cogulu

An 8-string moveable-fret acoustic guitar invented in Istanbul, built by luthier Ekrem Ozkarpat in 2008.

John Gzowski

43-Tone JI (after Partch) Electric

19ET Electric

31-Tone JI Electric

"Barstow" JI Acoustic

Neil Haverstick

19ET electric and acoustic guitar collection.

34ET electric and acoustic collection.

21-tone JI, 31ET and 36ET electrics.

Acoustic and electric fretless guitars.

Wim Hoogewerf

Movable-fret acoustic.

Glen Peterson

Just Intonation 'multi-tonic'.

36ET electric.

62-tone Just Intonation

"12-Tone Plus" JI Electric

Dante Rosati

A 21-tone color-coded just intonation acoustic.

Eduardo Sabat-Garibaldi

Dinarra, an enharmonic acoustic.

John Schneider

A universal microtonal guitar which uses interchangeable magnetic fretboards. The system is called Switchboards, invented by Tom Stone (U.S. Patent 4132143). NOTE: a similar system was invented and many such fretboards have also been made by giutarist Mark Rankin.

Listen to a New Sounds interview with John Schneider here.

Daniel Stearns

20ET electric.

Polymicrotonal 6-string Banjo.

24ET electric.

Fretless Les Paul (electric).

8 out of 13ET Tenor Ukulele.

Siemen Terpstra

Color coded Just Intonation acoustic.

Thomas Perronet Thompson

Enharmonic acoustic, from Instructions to my Daughter for Playing on the Enharmonic Guitar (1829)

Roberto de Vittorio

20 string Quartertone Acoustic.

Martin Vogel

Enharmonic Just Intonation acoustic, from On The Relations of Tone.

Self-Tuning Guitar from York, England

Photo links to the University of York Electronic Centre (pdf).

Self-Tuning guitar from TransPerformance

View an impressive video of this automatic tuning system in action.

Other Links

Microtonal Guitar website
Xenharmonic guitars wiki
Microtonal guitarist David Beardsley
A Meantone Guitar , by Graham Breed
A Justly-Tuned Guitar, by David Canright
Fret Placement Calculator, from Experimental Musical Instruments
Fernandes Fretless Guitars
Comments on Glued Frets, by Vincenzo Galileo
Instructions for refretting guitars, by Buzz Kimball
LucyTuned Guitars
Partch with his first Adapted Guitar
Information on 19 tone guitars, by William Sethares
Microtonal Guitar Conversion FAQ, by John Starret
Fretless Guitars from unfretted.com