ETI 603 Sequencer
Page One - Specs and photograph
Page Two - Schematic
Page Three- Front panel and PCB layout
Page Four - Article, parts list, and parts layout
Page Five - Front panel wiring diagram and photograph of finished unit
Circuit boards for this and other ETI projects are available for $22.00 Australian plus postage and handling from:
R.C.S. Radio Pty. Ltd.
651 Forrest Rd, Bexley, N.S.W. 2207
One person emailed me regarding a way to sync the sequencer to an external clock source. There's a relatively easy way to do this. Replace the Step switch connected to the 555 timer with the circuit below. This should allow syncing to any number of sources, whether it be audio, pulse, etc.
The circuit will trigger when a voltage over approximately 2V is present at the imput. The ratio of R3 and R4 sets the trigger voltage.
The JFET can be of various N-channel variety. The NTE466 is a very nice FET although it is fairly expensive. Others may work, but I haven't had a chance to try any out.
If anyone builds this circuit, please let me know how well it works. Since I haven't built the ETI sequencer, I cannot vouch for certain that the circuit will work.
Thanks go out to the following people:
- Tony Clark - Modification
- David Leigh - Circuit Board information
- Ken Stone - Schematics