AM1005 Mod Amp (2024 Edition)

OVERVIEW This 12HP module is a re-imaging of the four quadrant multiplier and VCA that ARP launched as the 1005 module in 1970, and which was included in the 2500 synthesizer. The AMSynths  electronic design is close to the original, with CV inputs and level potentiometers for the VCA, and audio inputs going straight into the four quadrant multiplier without level controls. The aim is to make the design user friendly and easy to use.

DESCRIPTION The module has a ring modulator followed by a VCA. It is designed to have two VCO's patched into the ring modulator, with the TUNE and RATIO controls varying the pitch of the VCO's by means of CVA and CVB  outputs.The ring modulator creates the sum and difference between the two oscillator frequencies. 

The ring modulator can be switched into two quadrant mode when it behaves as a simple VCA, with the Unbalanced GAIN control varying the level of the audio signal connected to INA. A front panel switch and a Eurorack GATE signal can be used to switch modes.

The ring modulator is followed by a transistor based VCA with GAIN control and three CV inputs; two of which have slide potentiometers for modulation depth. 

CONNECTIONS There are nine 3.5 mm jack sockets on the anodised aluminium front panel:

• INA, INB - audio signal inputs
• CV1, CV2, CV3 - 1V/octave control voltage inputs for VCA modulation
• CVA, CVB - precision voltage outputs
• OUTPUT - audio signal output

There are high quality Alpha rotary potentiometers for adjusting the gain of the VCA and for the  level of the input INA when modulation ifs OFF. There are Bourns LED slide potentiometers for adjusting the modulation depth of CV1 and CV2, which affect the VCA gain.

The module comes with a set of M3 mounting screws and washers, and a standard 10 to 16-way Doepfer power cable.

PRODUCT STATUS: IN PRODUCTION