AM1005 Module - ARP Modulation Amplifier

Overview  This module is a clone of the unusual ARP 1005 module from the mighty ARP 2500 Analog Modular Synthesizer. The module consists of a Ring Modulator which is internally connected to a standard ARP VCA. The Ring Modulator is based on the 4014 circuit used in the later ARP 2600, however the 1005 has the additional capability of generating inharmoinc preset voltages which are designed to be feed into the source VCO's.

The modulation effect can be turned off and on by the front panel push buttons or by a gating input and the VCA has both linear and exponential mode.

AM1005 Module My replica makes use of 2 previous designs the 4014 Ring Modulator PCB from Oakley Sound Systems and my own AM4019 VCA PCB. An additional PCB is needed for generating the Preset Voltages and the flip flop circuit for switching modulation on and off.

This module is built as a 5U high MOTM compatible design, as the original push buttons are so large that it would look very strange in a smaller format.

The module has the following front panel controls:

• Unmod Gain
• Amplifier Gain
• VCA CV1 Level
• VCA CV2 Level
• Ratio and Tune for the Preset Voltages
• Unmod and Mod Push Buttons
• Slide switch for VCA response - exponential or linear

There are 7x 1/4" jack sockets mounted on the rear the panel, these are:

• Modulation Gate In
• Audio Signal Inputs (x2)
• VCA CV Inputs (x2)
• Preset Voltage Outputs (x2)
• Signal Output

Module Panel Design The module uses the original push buttons, along with similar ARP style control knobs. The panel is 2mm aluminum and MOTM style 5U high,

ARP1005 Front Panel