Paia 9700 Semi modular synthesizer

The PAiA 9700 Series takes a decidedly high level, systems approach to Synthesizer Module design.  Rather than individual elements such as a single VCO, VCA or Envelope Generator, each PAiA module combines multiple elements and a powerful patch-over hardwired normaling scheme behind a single compact panel.  Common synth voices can be realized with few patch cords but elements can also be accessed individually for maximum versatility in creating complex, unique timbres.  A lot of synth power gets packed into a small space at a low cost.  Even a “small” system of only four modules, such as the P9700S, provides the sound generating power of as many as 15 conventional modules, including:

  • 2 VCOs
  • 2 VCFs
  • 2 VCAs
  • 1 Balanced Modulator
  • 1 Noise source
  • 2 AR Envelope Generators
  • 1 ADSR Envelope Generator
  • MIDI to CV Converter
  • Glide Processor
  • CV Scale/Offset Processor
  • Power Supply

System level design also improves performance and lowers cost.  Local voltage regulation and Star grounding on and between modules means a low noise floor and no parasitic modulations or interactions such as oscillator locking.  Distributing costs like circuit boards, panels and power connectors across multiple elements dramatically lowers per element cost.

All modules are scaled for 1Volt/octave Control Voltages with standard 100k ohm input impedance.  Nominal signal level is approximately +10dB.  Modules are designed for ±18V unregulated bipolar power, but ±15V regulated supplies can also be used.

Original 4700 and 2720 modules.

The original development project for PAiA’s 9700 series of analog music synthesizers was something of a sequel in its own right.  That work was inspired by requests from our friends to reissue modules from the 4700 and 2720 synthesizer systems.  The novelty of those modules remains because they represented something unique – a very simple and low-cost way to explore electronic sound creation.

Design of the 4700 & 2720 modules was constrained by a some very difficult requirements.  To make the kits inexpensive and easy to build, the designs had to use a minimum number of the most durable but affordable components in circuits that could be adjusted without sophisticated test equipment.

Given these constraints, the 4700 & 2720 modules were astounding successes.  Many thousands were successfully built. The price was certainly right:  4700 series module prices, circa 1978, cost between $22.50 and $38 (multiply by 3.2X to get 2009 pricing).  We know from our active service history that many of those systems live on, despite having been built by amateur enthusiasts in an amazing variety of circumstances.

John Simonton’s architecture for the original 9700 series modules was an evolutionary departure from modular synthesizer tradition (see his first chapter in The 9700 Chronicles ). He designed them to provide incredibly high functional density, with normalization that allowed many complex sound synthesis operations to be performed with very little patching.

Two features make the original 9700 series modules challenging to employ.  First, they are the most complex-to-build synthesizer module kits ever developed.  Second, the sophistication of their normalization scheme can be best appreciated by the user only after completion of the the assembly and setup of the module.

We restarted our development of 9700 series modules in 2006.  Our original goal was to provide a small set of low-cost “completer” modules allowing more elaborate synthesizer systems to be built wholly from our own catalog.  Our ground rules were:

  • Nearly goof-proof – extremely easy to build & set up
  • Easy to use
  • Very inexpensive.

Eventually, we decided that in order to please ourselves, we had to add the following requirement:

  • Performance sufficient for high-fidelity sound processing.

High-performance circuits that don’t require adjustment become more complex.  As we developed solid, better performing circuits with higher device counts, we knew there was only one way to meet our original goals: to assist the kit builder by performing some of the assembly in advance.  To turn this to the experimenter’s advantage, we worked to make the circuits customizable wherever practical.  The result was a new and unorthodox method of kit design, seen now in these second-generation 9700 series modules.

The 9700 development project continued to evolve at every turn.  Progress accelerated in 2008 when we were joined by our newest designer, Cliff Schecht.  Over the next year, Cliff took the existing design sketches and concepts and developed most of the new crop of modules with significant consultation from Geoff Schecht and feedback from the rest of us.  When David Arms joined Chuck McLeavy’s production team in 2009, these modules began to make the final huge leap from prototype to production.

Benefits from employing this new method of kit design have surpassed our expectations. The new crop of 9700 modules is utterly true to the original design goal:  basic modules at an extremely affordable price that are, by far, the easiest-to-build kits we have ever produced.  Even sweeter is that their performance rivals modules available from any manufacturer at any price.

Our final set of design goals, met with the new 9700-series modules, are:

  • Standard, basic, simple elements in a variety of functions
  • Compatible and/or easily adaptable to almost all modular synthesizer
    systems in:
    • signal levels
    • control voltages
    • supply voltages
  • Inexpensive
  • Durable & mechanically simple
  • Extremely easy to build
  • Option for affordable ready-made product
  • Premium fidelity in signal path
  • Compact & low-power
  • Low cost, comparable to original 2720/4700-series pricing
  • Easily adapted to fit any modular synthesizer format
  • Additional packaging and power options.

Each of the circuits employ the following features to improve performance and reliability:

  • Only high-quality capacitors are used in the signal path, but these components are provided as through-hole components so that owners may replace them with even more esoteric components as they may choose to suit their preference.
  • Attention is paid to signal fidelity throughout the system:
    • low-distortion op-amps
    • direct-coupled amplification wherever possible
    • local linear power regulation
    • low-noise layout
      • compact, double-sided boards with ground planes
      • excellent decoupling
      • system star grounding throughout
    • SMT components, where used, employ larger packages (0805, SO-DIP, SOT-23, etc.)
  • Extremely limited point-to-point wiring
    • power harness is pre-wired
  • Power inputs to each modules are regulated (with bypass) and protected against over-voltage.

The new modules we have released for this series are a start in a new direction for modular synthesizers.  An exciting path lies ahead of us and we are excited to have you join us for this journey.

Text (c) Paia electronics, kindly reproduced.

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