Dave Smith Instruments DSM01 Curtis Filter

Known for their great in-depth reviews, SonicState/Soniclab has published another long video demonstrating Dave Smith Instruments' latest product, the Dave Smith Modular DSM01 Curtis Filter, that was released earlier this year.

Dave Smith Modular
DSM01

" The module takes its name from the original filter chip designed by the late Doug Curtis and provides both a switchable 2/4-pole low-pass filter and a VCA.

The Curtis filter is an integral part of the sound of many synthesizers created by Dave Smith, including the classic Sequential Circuits Prophet-5 and Pro-One, and more recent instruments such as the Evolver, Mopho, Prophet ?08, and Prophet 12.

The “Curtis sound,” which is often described as saturated, brash, and powerful, was fundamental to not only Smith’s synthesizers, but also to such highly-regarded instruments as the Oberheim Xpander, Rhodes Chroma and Polaris, PPG Wave, Korg MonoPoly, Waldorf Wave, Elka Synthex, and many others.

“We wanted to make the classic Curtis filter sound, which I’ve always found very versatile and expressive, readily available to modular users,” said Smith. 

“Adding the DSM01 to a modular system is an easy way to give it the sonic edge that people typically associate with a vintage Sequential synth. 

But it’s also a big part of the sound of my current synths such as the Prophet 12.”

The module is a standard 8HP wide, Eurorack-format device with interconnections made using 3.5 mm phone jacks. 

A set of inputs and parameters allows voltage control of filter frequency and resonance. 

Filter slope is selectable between -12 dB and -24 dB. 

The module also provides its own VCA and features two separate outputs for the filter—one pre-VCA and the other, post-VCA. 

A unique feature of the filter is a Boost function that introduces harmonic distortion into the signal for more aggressive coloration."

Video: DSM01 Eurorack Curtis Filter - Dave Smith Instruments
" The first module from Dave Smith is the classic Curtis Filter. In 8HP it also has a VCA to further expand the features available in such a small module."

Find out more at http://www.sonicstate.com/news/2014/10/06/sonic-lab-dsm01-curtis-filter-eurorack-module

Video uploaded by sonicstate 

Twitter: Sonicnick

Doepfer Sound Sampler (1984)

Doepfer 8-bit Sound Sampler

On a random search on the internet for rare Doepfer products i came across this module in an old Matrixsynth post:
This Doepfer Sound Sampler module (8 bit voltage controlled sampler with interface and sampling software for Commodore 64) was made by Doepfer in 1984.

Sound Sampler book 
by Dieter Doepfer and 
Cristian Assall

The Doepfer CV/Gate controlled modular Sound Sampler system was available as a kit between 1984 and 1990.
The complete system was also described in detail in the book written by Dieter Doepfer and Cristian Assall called "Sound Sampler" (published by Elektor ISBN 3-921608-44-9) in 1988.
This book was dedicated to building an 8-bit modular sampler that could be edited with a Commodore 64 home-computer.
All schematics are in the book, with all PCB designs and front-panels for all modules: input, memory/sampling card (with CV/Gate), loopcard, C-64 interface and compressor/expander.

Picture via Gearslutz

Every sampler module had its own memory.
There was software available that could handle sampling, FM synthesis, Wavetable synthesis, Fourier synthesis and Waveshaping synthesis.
The C64 could be used only to modify the sampling memory (sampled sound or sound generated by software synthesis like FM or Fourier), up to 8 sampling voices.

Most of the PCB board was covered by the memory chips that were pretty expensive at the time.
The picture below shows a 6-Voice system, the Input/Interface module is left, then 6 times the Memory-Card, each with a HS-VCO to get the pitch and a Curtis filter.
Apart from the sampler was a CV/Gate controlled stand-alone unit (not on the pictures)

Later Doepfer added another extension card, the so-called CCU (computer control unit). 

With this unit it was possible to define loops with free adjustable start and end position (the software helped to find zero-transitions for a glitch-free loop), and the unit could now be fully controlled by the computer (also pitch via high-speed DCOs). 

Also an expander/compressor was available but the improvement of this addition was very small from Dieter's own point of view.

6 x Memorycard, 6 x VCO,
6x Curtis filter

Around 300 kits were sold, partly because around the same time (1984-1988) Ensoniq released their Mirage sampler that was cheaper (and easier to use) than the Doepfer sampler.

Dieter: "To some extend this was also the beginning of the Eurorack standard (instead of Doepfers/DD Systems earlier Formant sized modules) as the front panels already had the same dimensions and mounting positions as the A-100 that started in 1995."

This module was the precursor of the A-112 that was released more than a decade later, but in the A-112 one small chip contains twice the memory of the 16 large chips of the old sampler.

Special thanks to Dieter Doepfer for all additional info