The 40235 Dual Filter Module integrates the circuitry of two of the most
popular voltage controlled lowpass filters, the ARP 4023 and 4035, onto
a single board. The 4023 is the filter found in early Odyssey synthesizers
(model 2800), a 2-pole (12 dB/oct) OTA-based biquad design. The 4035 is a
4-pole (24 dB/oct) design built around Moog's transistor ladder, and was
originally installed into Odyssey models 2810-2812. This rather rare
filter is similar to the 4012 filter which was used in early model 2600
synthesizers, although it uses IC transistor arrays instead of matched
discrete transistor pairs.
The upgrade adds a front panel control for switching between 2-pole and
4-pole filter modes.
The 40235 is signal compatible with ARP 4035 and 4075 filters, and can be
used as a direct replacement in the following instruments:
|AXXE-2||(models 2310 and higher)|
|ODYSSEY-2||(models 2810 and higher)|