This page is for those who wonder what's inside the Proteus/1 and Proteus/2 sound modules. Click each thumbnail for a larger picture. The pictures also serve to answer a question I sometimes receive about the expandability of the Proteus/1.
A stock Proteus/1 contains 4 megabytes of sound samples. The sound samples are contained in Read Only Memory (ROM). These ROMs are the large chips shown in the P1-1 picture. They are not removeable. If you look carefully, you will see two rows of holes on either side of this group of chips labeled CN2 and CN3. This is where a second circuit board, containing an additional 4 megabytes of sound ROM could be installed thus "expanding" the ROM memory to 8 megabytes. When expanded, the CN2 and CN3 connector holes are fitted with pins. The second circuit board, containing the additional sound ROMS, is stacked above the existing ROMs and plugs into the pins.
A stock Proteus/2 contains 8 megabytes of sound samples. As can be seen in the P2-1 picture, a second circuit board is present in the Proteus/2 unit. The additional 4 megabytes of ROM was needed to hold the orchestral sound samples of the Proteus/2.
In the past, an expander board made by Protologic was available for the Proteus/1. The Protologic board contained 4 megabytes of ROM with additional instrument sound samples. Following Protologic board purchase, the customer sent their Proteus/1 to Protologic where the connector pins and circuit board were installed. The Proteus/1 was then returned to the customer with an additional set of presets; many of which were part of the then new GM standard.
Proteus/1 and Proteus/2 were manufactured before GM (General Midi). GM standardized
the first 128 presets with respect to instrument and patch number. GM compatible
sound modules could reasonably play MIDI files that were developed using other sound
modules. Using the Protologic board, along with some preset editing and patch number
mapping, Proteus/1 could be made to emulate the GM patch numbering standard. But new
lower cost GM sound modules and soundcards soon came to market with superior sound
quality. The Protologic board was only manufactured for a few years.