|
AM2200 Module - Eµ VCO
Overview This module is a replica of the main VCO used in the Eµ Modular from 1972 - 1980. Dave Rossum originally designed this VCO back in late 1972, and the core sub-module is the
1200. The design was updated in the mid-70's as the 1201 but it remained largely unaltered until the end of the Modular production line.
The VCO produces a sawtooth which is then converted into triangle, sine and pulse waves. The
pulse width is variable from 0-100% and the frequency range can be switched low to turn the module into a LFO, with a lower frequency of one wave every 33 seconds. The VCO is temperature compensated and it has low jitter and excellent HF
tracking (0.25%).
The VCO provides an adjustable and inverted mix of all waveforms plus full volume outputs on every waveform at 5V peak to peak.
The updated 1201 VCO has a hard sync input, as well as a linear FM input. Some
components maye have been upgraded, and a LM394 dual matched transistor is used instead of the AD818.
AM2200 Circuit
The AM module is an exact replica of Daves original design with only minor cosmetic enhancements and the use of some modern components. The excellent analog design remains unaltered. The module uses two PCB's, the main VCO 2200 and the Wave Converter 2210.
The cosmetic improvements include:
- Re-positioning of the front panel controls to enable the PCB's to be mounted to the front panel
- Front panel Bi-colour LED for LFO frequency (RED) or VCO on (BLUE)
- Hard Sync Amount front panel control
The circuit is temperature compensated with a 3600ppm 1K PTC resistor and uses either
an LM394 dual matched transistor array or the higher quality SSM2210P for the exponential generator.
Front Panel
The front panel is a standard AM design, 180mm wide and 4U high, with black lettering. Controls knobs are standard 19mm diameter Eµ Modular.
Build History
The schematic was transferred into Eagle CAD in February 2005, and two 120mmx100mm boards laided out. A prototype module will be operational in the spring of 2005.
|
Site Options
Resources
* AM FAQ's 
* AM2200 Project Notes
* AM2200 PCB layout
* AM2200 front panel