Matrixsynth

images via this auction


"Apple ][
Alpha Syntauri
Mountain Computer Music System

Complete Apple //e based setup
Fully working, with lightpen, monitor, disk drive, manuals

This auction is a genuinely rare chance (I hate the phrase, but I haven't seen one of these on auction for a year at least) to obtain a Mountain Computer Music System based AlphaSyntauri. This is a digital synthesizer and sequencer package dating from 1979-1982 in terms of hardware - they went out of production in 1985 or so. It is very similar to the Passport Soundchaser system. The complete setup consists of:

AlphaSyntauri "Pratt & Reed" based 61-key velocity sensitive keyboard, which I have rebuilt and cleaned with new bushes. It would benefit from replacement of the foam damper strip along the base below the keys which has disintegrated with age, but this is largely a cosmetic component. This is the same key mechanism used by many classic synthesizers. There is also an interface card for the keyboard.

AlphaSyntauri's preferred bundle of the "Mountain Computer Music System" voice cards - 8-voice (technically 16 oscillators) stereo sound generator and interface board with lightpen, with wavetable synthesis. This has the original box, in poor condition, and manual (no original disks). The system was also available with three-voice square wave cards from A.L.F, which are very limited.


An Apple //e unenhanced system. To be chronologically correct, this should have a ][+ or //e, this is the nearest I can get to a ][+. Enhanced //e models have timing issues. This is equipped with a duodisk disk drive and interface card, and a Philips monitor of suitable persistence for the lightpen to work. It is also equipped with a higher-output, better cooled AE PSU which should make it rather more reliable despite being 25 years old. In the picture, an 80 column card is visible - this is included in the auction but will not be fitted, as it appears to cause minor timing issues with the synthesizer (I added it to the system to include with the auction then remembered why I removed it!).

Software, including the B3 wavetable generator. This is quite complicated to use, but the results are impressive. To be fully useful, the software needs Apple II paddle controllers - either the later, 9-pin D-sub connector type or earlier ones that connect internally. I no longer have a set of these, but will attempt to locate some before the auction ends. They sell for a few bucks on eBay US when they come up.

It's hard to really fully explain how main "MetaTrak" system works, but it features a sixteen track sequencer, is multi-timbral, and quite flexible. By 1979 standards, it was absolutely stunning. Rather than try and explain what it sounds like, here's a link to a recording of a demo track provided with the system called Galaxy Gap [player above] - this has been played back directly from the system for sale, recorded by myself. It is not multitracked or processed in any way. During playback, the notes are represented on screen in a similar style to the panels on "Close Encounters" - when using other software modules, they are bar-graphs showing velocity.

You can play live over an existing track in MetaTrak. Other software has different features; documentation for the Mountain Computer Music System is included but I had to dig around the internet to find out how to use a lot"

Also see this post.