The CMS 1006 module is a top shelf quality reproduction of the world famous ARP 1006 Filt-Amp module in Euro-Rack form. The 1006 module was the basic building block for the ARP 2500 synthesizer. CMS has made this critical component used in the ARP 2500 available again in a high quality version of the euro-rack format.

CMS Module 1006 is a functional circuit package designed for use with the CMS Series 1000 electronic music synthesizer modules. This unit contains a four-input audio mixer, a voltage controlled low-pass filter (VCLPF) plus a voltage controlled amplifier with associated circuitry.

The cutoff frequency of the filter may be varied by external voltages or by the front panel fc control. There are three separate filter control inputs at the bottom of the module. The inputs are each associated with an attenuator. With the attenuators rotated fully clockwise, the sensitivity of these inputs is 1 volt/octave. Input #7 is pre-patched to the internal CV buss. This pre-patch can be overridden by inserting a jack into input #7. The voltages appearing at each control input are summed internally and the cutoff frequency of the filter will be determined by this sum. Although the sum of all the control inputs may exceed the effective input range of the filter, (i.e., +10v) no damage can be done to the circuitry by such overdrive.

A resonance or "peaked" response at the cutoff frequency may be obtained if so desired. This is useful for creating certain types of formants, such as "wa-wa" or "yeow" effect. A knob control permits adjustment of the height of the resonant peak.
Up to four audio signal inputs to the filter may be mixed and their relative amplitudes adjusted by means of four panel knobs.

The voltage controlled amplifier (VCA) accepts the output signal from the voltage controlled filter (VCF) and modifies the signal level according to the sum of a local control voltage (supplied by a panel knob control) and a number of external control voltage signals.

The voltage controlled amplifier may be operated in two modes simultaneously, unlike the origianl ARP module. The exponential input has a control transfer function of 10 dB per volt. The linear inputs have a control function of Vout = VcsVin referred to a 400 Hz sine audio input signal applied to one of the Filt-Amp audio input terminals with the corresponding audio control knob in the extreme clock-wise position, the filter in the wide band condition (sum of control voltages = +10v) with the filter cutoff frequency knob in the extreme clockwise position and the resonance control knob in the extreme counter-clockwise position.

The range of the voltage controlled amplifier is over 100 dB, which permits the VCA to be used as a squelch gate control device. By proper adjustment of controls no discernible output should be obtained in the absence of control voltages, even when the audio inputs are operated at maximum levels.

CMS has decades of extensive knowledge and experience building, testing and repairing many different incarnations of the Moog transistor ladder filter. We have taken this expertise and applied it to the euro-rack world.

The 1006 filter section is ARP's version of the transistor ladder filter. It differs from the 4012 ladder filter used in early 2600s because it uses a purely bipolar transistor signal path. It has a warmer sound and a different frequency response than the ARP 2600 filter. The resonance on this filter sounds different than the 2600 filter also.

Using the 1006 low-pass response in series with the 1047 high-pass function enables the user to accurately reproduce many of the classic ARP 2500 sounds. You can now realize this sound in your studio with the 1047 and 1006 from CMS.

If you want to reproduce the sound of the ARP 2500 exactly, check out our other 1000 series modules available from CMS. They are all based on the ARP 2500 system.

FEATURES:

This complex circuit utilizes an all-bipolar matched transistor signal path to produce it's distinctive and highly resonant sound.

High quality construction and top shelf components, Switchcraft jacks, Alps attenuators.

CMS engineering used in many professional recording studios across the USA and Europe.

Main frequency control pot features an extra large geometry "virtual infinite resolution" potentiometer for accurate control of frequency.

The VCF has 3 control voltage inputs with attenuators fixed at 1v per octave.

The VCA has 3 control voltage inputs. 2 linear control inputs: one fixed and one with an attenuator. 1 attenuated exponential control input

Easy to understand flowchart front panel graphics facilitate operation.

The new improved front panel is now made of a special material that has the image impregnated into the aluminum surface. It will not fade over time or wear off from finger action.

Alan Pearlman was a pioneer of audio design long before he created ARP instruments. He worked for George Philbrick at Philbrick Researches where he designed ground breaking discrete operational amplifiers including the P65 and the P75. The P75 used darlington transistors. Alan claimed (to me personally) that he and Sidney Darlington invented the Darlington transistor at the same time - but Darlington published first. He then went off to form his own precision operational amplifier company - Nexus Research.

The filter in the CMS Module 1006 is a faithful reproduction of Alan Pearlman's version of the transistor ladder filter. This enigmatic circuit utilizes several matched discrete differential pairs and hand matched capacitors to produce it's distinctive and highly resonant sound.

The unit consists of a highly resonant low-pass filter with voltage controlled frequency. The filter is capable of providing a wide variety of formant shaping and tonal modulation.

The cutoff frequency of the low pass output is referred to as "Fc". Fc may be set by the frequency knob over the range of 16 Hz to 16 KHz. Control signals applied to any Fc input will change the cutoff frequency from the knob setting by 1 octave per volt when the knob above the control input is at maximum. Control signals from the individual inputs are summed with the Fc knob controls, and may be positive, negative, or audio.

With the RESONANCE (Q) knob at minimum:

The low pass output has unity gain from 16 Hz to to 20 KHz and attenuates 24db per octave above Fc.

As the RESONANCE (Q) knob is turned up, a resonant peak occurs at Fc

The dedicated v/oct input #7 is calibrated to a 1V per octave scale.