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Roland System 700 Modular Synthesizer
Technology, Cloning
Overview Roland were the last
major synthesizer manufacturer to enter the analog modular market in 1976. This meant they could learn from previous designs, both in terms of electronics and user interface.
The System 700 was the result of 2
years hard work, and Roland suceeded in producing one of the best analog modulars ever. They created around 20 different modules, plus a keyboard controller and put them in a fixed configuration. The design included:
- A fixed configuration of modules in 6 cases called blocks
- Sliders used for many controls, to give improved visual feedback. VCO's used roatary controls.
- Pre-patched connections plus 1/4" jacks sockets
- Stable and wide frequency range oscillators
- A variety of VCF's - 24dB low pass and a state variable
- Fast ADSR envelopes (2ms)
- Green signal and red overload LED's on all modules
- A large and heavy format, the main modules are 280 mm high. The complete synthesizer is over 1.7m wide, 1.1m high and weighs 212Kg.
The System 700 was aimed at high ends studios in Japan and the
USA, and cost US$14,500 in 1979. Although Roland created a smaller and cheaper model (The Laboratory System - with Blocks 2 and 8 at US$3,300) it never sold in large numbers, maybe 40 were
manufactured between 1976 - 1982. The System 700 was Rolands flagship product, until the Jupiter 8 arrived in 1980.
Blocks The System 700 was an important development for Roland
as it provided a platform for pioneering new analog designs, some of which were shared with the contemporary but smaller System 100 modular (such as the same analog sequencer core). These
designs also rippled down to the SH mono synth range and ultimately the System 100M of 1979. The "blocks" are:
- 1 - Main Console with 3xVCO's, 2xVCF's
- 2 - Keyboard Controller with 5 octave keyboard
- 3 - Analog Sequencer (10 x 3)
- 4 - VCO Bank, 6xVCO's, LFO, Mixer, S&H and 2xADSR's
- 5 - VCF/VCA Bank, 2xVCF's, 3xVCA's, 2xADSR's, Gate Delay
- 6 - Interface & Mixer
- 7 - Phase Shifter and Audio Delay
- 8 - Lab version
Technology
The System 700 makes use of early 1970's analog technology, such as the uA726 dual transistor, CA3080 OTA chip (1969), and the single 741 (1968) Op Amp and its dual variety the
CA1458. This is quite a traditional and safe approach, which was certainly an improvement over Moog and ARP designs but not as advanced as the designs coming from Dave Rossum in E-mu
Systems - who was already using high quality Op Amps, and working on micro-processors and custom synth chips.
Roland did exploit the newly available FET Op Amp (CA3140), CMOS logic for the sequencer, and some strange TV chips for
decoding in the analog sequencer. Roland soon moved on from the rather weak CA3080 and used an improved OTA chip the BA662 as the basis for future mono-synth designs, including the popular
SH101. However using standard components means that a lot of the System 700 parts are still freely available, even if the 741's should be upgraded in the audio paths!
Cloning
The System 700 is a good cloning target, as some of the modules use currently available analog chips, the voltages are compatible with modern modulars (+/-15V power rails and 10V p-p
signal and control voltages) and the designs sound good too!
Let's first discount the impossible and unattractive modules:
- 701 Keyboard Controller - dual voice
- 702 VCO - ua726 heated transistor pair
- 708 Noise - traditional design with okay pink filter
- 708 Ring Modulator - basic MC1496 design but no trimmers!
- 709 Sample & Hold - FET based, similar to 100M version
- 711 Reveb & Panning - many alternative designs
- 712 Monitor - nice reference oscillator with coils
- 717 Sequencer - strange decoder chip
- 714 Interface
- 716 Mixer - modern op amps are way better!
- 720 2 CH Phase Shifter - 8 stage 741 design
- 721 2 CH Audio Delay - analog BBD device (MN3004)
This leaves the following modules that can be cloned:
- 703A Multi-mode 2-pole filter - based on CA3080
- 703E 24d Low Pass VCF - based on CA3080
- 704 VCA - traditional CA3080 design with linear/exp control
- 705 Dual Envelope- 1458 Op Amps and transistors
- 706 LFO - a dual transistor and unijunction tranny
- 713 Gate Delay - 555 timer based Lag Procesor
- 715 Fixed Filter Bank - dual Op Amp based
- 723 Analog Switch - FET based
Will we be building any clones? Well the LFO is rather cool with
delay and voltage control but it needs the BA662 replacing with a CA3080 and buffer Op Amp. The VCA is very similar to the already cloned E-mu Systems CA3080 design, and the 24dB filter is
probably better implemented by Formant. The multi-mode and fixed filters are worth cloning, as is the Gate Delay.
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Product Spec
* Analog Modular Synth
* 701 Keyboard Controller
* 702 VCO
* 703A/B/C Mult-mode Filter
* 704 VCA
* 705 Dual Envelope
* 707 Amp/Enevlope
* 709 Sample & Hold
* 711 Reveb & Panning
* 715 Multimode Filter
* 717 Analog Sequencer
* 721 2 CH Audio Delay