Tetra GmbH is a German company that made custom-cased Atari Mega ST and TT solutions in the past. Their approach involved re-casing original Atari motherboards and enhancing them with their own and third-party add-ons to make them more powerful. 

ST-Line

First, the Megas ST came out, called "Manhatten" tower. There were two tower versions for this model.

• M68000 16Mhz, 16KB Cache, 4MB

• TOS 1.04 and GEM

• Teac 3.5" and 5.25" floppy drives

• SCSI hdd (Seagate ST- 1096N in mine, 84MB)

• German keyboard

• 456x190x620mm, 20kg

A wide range of  options were available during purchase (here is a few):

• MC68030/25, TOS030

• MC68881-16 or 68882-25 coprocessor

• AT Speed 80286 with supercharger and MS-DOS

• SyQuest SCSI drive/Streamer /Magneto Optical Disk drives

• Tetra UPS

• Graphic Cards up to 1280x960/256 colours

• Printers

More details about these options are in the manual I made available. Uploaded to Atari archives (https://docs.dev-docs.org/).

My ST-Line Tower has the 2x TEAC FDDs, the SCSI ST-1096N is going through an ICD AdSCSI host adapter (mounted at the back). I had to replace this drive since it was very unstable, so there is an SCSI NEC D3856 105MB in there now. Crazy Dots Mega ST version graphics card and a Fast Technology 030/50Mhz card with TOS 2.06.

TT-Line

The high-end Tetra version only had one type of case but in two different colours (white and black). These were fully galvanized metal cases with special attention to details. There are less mods in these since the TT was top of the range, with ability to handle varoious hw without extra cards, hence the adapter board is the main thing in there. So they're like standard TTs with extra cards. Mine had a TC1208 graphics card.

• TT030/8MB RAM

• Teac 3.5" and 5.25" floppy drives

• SCSI hdd (Maxtor, 213MB)

• Syquest 44MB, SCSI

• 420x180x630mm, 21kg

Beside the hardware modifications Tetra supplied software for the mods. There is a custom welcome screen and a Control Panel option for the expansion card, that is initialized during boot through INIT.PRG

Scanned German Owner's manual

Scanned German Installation guide

Tetra specific software  (ST and TT)

ST-Line Gallery

TT-Line Gallery

Related links:

https://www.stcarchiv.de/stc1990/06/manhatten-st

https://tetra-software.de/firmengeschichte

https://www.stcarchiv.de/tos1991/04/tower

https://www.atari-forum.com/viewtopic.php?t=45055

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30-05-2025