At the moment (2021) not much is known about the exact instruments that Hand Reichel built, with the exception of the Daxophone, which is a well documented instrument with many copies being made by various makers around the world. Reichel made many experimental guitars which are poorly documented.

The Daxophone is by far the most famous instrument built by Hans Reichel. The instrument has become a sort of icon for the experimental musical instrument world and is one of the few to be openly adopted and played by many experimental musicians. Part of the success of the Daxophone can be attributed to the detailed construction guide that Hans Reichel made.

Here is the Daxophone Information PDF taken from the now defunct Daxophone website. This document details the construction process for a Daxophone. I have taken the liberty of hosting it here since the original website is difficult to access (see notes). ¹⁾

In the 1989 Guitar Player Magazine article ²⁾ the daxophone is called a “dachsophone” and claims that “dachs is German for “Badger””. It is very likely that at this time the early version of the instrument was called a Dachsophone. The article also strongly suggests that the Daxophone was invented in 1986, which is the same year as the below video, which demonstrates a very early performance of the instrument. Note the rather underdeveloped technique and sound as compared to later recordings of Reichel.

Two instruments are detailed in the 1989 Guitar Player Magazine article ³⁾, one with a wider electric guitar shaped body and one called the “Stick” which has a minimal acoustic body and is generally stick shaped. These two guitars utilize a 3rd Bridge. Reichel describes having discovered the underlying harmonic principles in 1980.

The instrument in the below video looks very similar to the wider of the two guitars discussed in the 1989 article but the instrument looks to have a number of additional pickups and a movable bridge present and looks to generally be in a different stage of construction. The video description also calls the instrument the Pick-Behind-the-Bridge-Guitar, which is mentioned but not explicitly shown in the 1989 Guitar Player Magazine article.

There are two guitars depicted in the 1989 Guitar Player Magazine article ⁴⁾ of guitars with additional frets added that go so far as to act as bridges across the sound hole of the guitars. These may represent some of Reichel's early experiments with playing mas many harmonics as possible on the guitar. These guitars are describes as being made in 1978.

Made in 1974, no other unusual features about this guitar are known, the 1989 Guitar Player Magazine article ⁵⁾ says that this guitar is played using an “electric razor”, which suggests that the unusual acoustic properties of the instrument might come from the use of the razor and not a permanent modification of the timbre of the instrument itself.

An instrument made in 1974 simply described as having “an extra pickup mounted at the nut.” is shown in the 1989 article ⁶⁾. No further information is known about the instrument but his interest in picking up sound from “the wrong side” of the guitar is a common talking point Reichel makes about his experimental guitars.

A short narrative about Hans Reichel by Daniel Fishkin and that details making a Daxophone in his studio ^{7) 8)}
Part 1 Introducing the Daxophone by Daniel Fishkin⁹⁾
Part 2 How to Build a Daxophone Soundbox by Daniel Fishkin¹⁰⁾
Part 3 The Mystery of the Acoustic Cantilever: Building a Dax for Your Daxophone by Daniel Fishkin¹¹⁾

Again a link to the original PDF on how to build a Daxophone ¹²⁾

Crossing the Bridge by Hans Reichel, by Joe Gore that appeared in Guitar Player Magazine, 1989 ¹³⁾
This article details the names of many of Reichel's early instruments

The original website daxo.de is not readily available because it was running adobe flash, if you have the ability to view the website using a lineage viewer, the original website is still viewable ¹⁴⁾
Here is a youtube video detailing the website as it was intended ¹⁵⁾

I find the video of Reichel's Pick-Behind-the-Bridge-Guitar really fascinating because the video is from 1986 which seems early for experimental guitars like this. This is a point that needs more research as I also think Bart Hopkin and Yuri Landman drew inspiration from these experimental guitars.