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AM2500 - Eµ Modular Sequencer
Introduction
Some of the products from E-mu Systems have been born out of dreams, or at least making sure Dave was sent off on holiday to relax and think up amazing new ideas! The E-mu Systems Modular Sequencer concept was born out of a back packing trip in 1973 where Dave was supposed to be switched off from E-mu Systems. Lying in the sun he dreamt up a modular approach to building a digital and analog sequencer, where the user can expand the sequencer incrementally, rather than being stuck with a single fixed module.
Released in 1974 the Modular sequencer was a major innovation. It contained both a standard 8-step analog sequencer, and one of the first digital sequencers ever manufactured. The digital sequencer could be easily expanded from a
basic storage of 128 notes to many thousand. It had both step and real time entry of note and gate data, and a tape backup unit for storing sequences was added in 1976. Whilst E-mu Systems did implement microprocessor software based
seqeuncering in the 4060 keyboard and Emulator I, this hardware seqeuncer never got a microprocesor upgrade.
Unfortunately the high cost of 1k bit RAM in the mid 1970's meant that few of these unusual sequencers were ever made,
possibly less than 25. By 1980 the design was effectively obsolete when Roland brought out the MC and CSQ digital sequencers - which used microprocessors.
AM Replica In 2005 Riley Smith at E-mu SYstems was kind enough
to send me a copy of the original schematics and board layouts for most of the modules. This meant a replica of this unusual and powerful seqeuncer could be designed and built. The original modules have been carefully replicated but with
improvements enabled by modern technology. See the left hand side bar for details of each module.
Project Status
The AM2500 Sequencer is well on the way to being built. The schematics have been transferred into Egale CAD and PCB layouts are in development. A variety of upgrades are being installed to improve the accuracy of the control voltages, to enable control voltages to be stored in non-voltaile memory and even a new programmable control voltage module with 64 memories.
Unusual parts have been located, such as the small bubble display LED's. The AM2540 is the first module to be at prototype status in spring 2006. The other modules will follow over the next few months and by the end of 2006 the
project will be completed. PCB's or completed seqeuncers may be offered for sale, so email me if you are interested in this project.
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