AM1013 Octave Fixed Filter Bank

14 HP | AM1013 Octave Filter Bank | User Manual (PDF) | You Tube

OVERVIEW This 14HP module is a re-imagining of the ARP 1013 octave filter bank that was announced in 1970 by Tonus as part of the 2500 Synthesizer, but it never made it into production. It consists of eight band pass filters with their cutoff frequency spaced one octave apart, from 63Hz to 8kHz.

The filter is very useful for creating formant and vowel sounds. The individual outputs enable voltage control of the filter by using eight external VCA's - for example the 1032 Mixer & Distributor module.

DESCRIPTION The AM1013 is based on contemporary Op Amp based filter bank designs, such as the EMS Eight Octave Bank from April 1971. It uses a 12dB high pass filter in series with a 12dB low pass filter to create eight band pass filters that are connected in parallel and set one octave apart. The filters have a fixed frequency and Q of 5.0. 

The eight filter outputs are mixed into a single output with two jack socket. Each filter can be adjusted for level using the ARP 2500 style control knobs. The input and output levels can also be adjusted using the front panel potentiometers.

High quality WIMA polypropylene capacitors have been used to ensure a beautiful sounding filter. The filter has a bypass feature which can be set using the push button switch (with green LED). 

The wide frequency range from 16Hz to 8KHz, Q of 5.0, individual outputs and high quality sound  make for a unique module that takes its heritage from 1971.

The 1013 pairs nicely with the 1032 Mix & Distributor module, where each band pass filter output is patched into a VCA, enabling time domain mixing of the fixed filter sounds.

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

• IN 1, IN 2 - audio signal inputs with level control
• OUT 1, OUT 2 - audio signal outputs with level control
• INDIVIDUAL OUTPUTS - eight direct outputs, one from each filter

There are high quality Alpha rotary potentiometers for adjusting the level of each octave filter into the final mix, and for adjusting both the input and output levels.

The module has original ARP 2500 style knobs manufactured by Rogan in the USA.

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

MODULE STATUS: IN PRODUCTION