Hey LoveR, not that I'm much of a Tietchens fan, but I picked up a few releases that I ran into over the years. Here's a short rundown of what I have...
Spät-Europa and In die Nacht, both from his early 80's stint with Sky Records. Features sort of goofy, whimsical synthesizer pop with state of the art electronics, vocoders, and rhythm boxes. Next to one of the track titles on the cover of my Spät-Europa LP, a previous owner has scribbled "Ralf Lundsten" which should give you an indication of the merits of the music. However, at it's best moments, I think some of the material resembles the Residents. Spät-Europa also embraces a sort of punk aesthetic, in that all tracks clock in at around two minutes. On In die Nacht Tietchens lets the tracks evolve more, which they certainly benefit from. But apart from their status as historical artifacts, these records don't have much for them anymore. I believe even Der Man himself frowns upon the Sky years today.
Abfleischung -- the coolest thing with this record is the subtitle, "Festmusik zum 3. Symposium der Aktionsgemeinschaft Pädophagie als postnatale Geburtenkontrolle". Sounds like the name of an Einleitungszeit album, right? This is a pretty scattershot affair that displays loads of different styles that Tietchens have explored. From very abstract musique concrete pieces to more droning, industrial soundscapes. Some is OK, some is darn near unlistenable, to my ears at least.
Marches Funebres -- I have the CD reissue which also tacks on the Zwingburgen... piece. I agree, it is quite horrible. But the two other tracks, the A and B sides of the original LP respectively, are probably the best I've heard of any Tietchens. This could also be filed under "dark piano music" of a kind of cyclical nature... repeating patterns and such. Parts have a very orchestral feel, even with some neofolk elements... snare and pounding tom-toms.
Sinkende Schwimmer -- I remembered this as quite good, but renewed listening stifled my previous enthusiasm. Most of it is very difficult to digest, very abstract, academic, austere sounding experimentations. There are some tracks that rely more on reverb and other effects that have a Cranioclast feel to them, which saves this album for me. Thomas Köner supplied the sources for some of this material, btw.
7 Stücke -- a collaboration with Jon Mueller, some American improv drummer I've been told. Here we have collages of concrete sounds, I believe Mueller's percussion that have been processed by Tietchens. The result reminds of some Kapotte Muziek. A quite decent effort, for those into that style.
Then I've listened to some of Asmus' more recent "menge" albums, that positions him in a more contemporary glitch/clicks'n'cuts context. I don't like it at all, but perhaps it's just an honorable effort to push him into the arms of a new audience.