Overview Wolfgang Palm developed the 300 series modules as a replacement for his original Moog Modular like 100 series in 1976. He re-used some of the circuits and added new front panel designs. The 300 series consisted of 14 modules, plus cabinets and keyboards.
Klaus added a full set of PPG 300 analog modules and two PPG analog sequencers in 1976, and placed them on top of the Big Moog, where the ARP 2600 and EMS 8 Octave Bank usually lived. The PPG setup replaced the Synthanorma SQ312 analog sequencer, and his ARP 2600 in the live rig.
This 300 modular system probably cost £15,000 in today’s money (DM 8000 at the time), the 314 sequencer was particularly expensive. He kept the PPG Modular setup until he moved onto digital synths in the early 1980’s, and it seems to have been sold quickly, whilst the Big Moog survived in his studio until 1996.
The Moog IIIP only has a few filters, and you can see the 904C set to Band Reject, so I am sure Klaus enjoyed the additional PPG sounds. He expanded his live rig into the late 1970’s with two Minimoog’s and a Multi Moog, so he loved the Moog filter. In 1980 Klaus swapped out the 991 and 994 and put two PPG 303 VCF/VCA modules into his Big Moog.
The left hand rack contains two sets of 314 sequencers and 313 analog switches. The right hand rack contains a three VCO mono synth, consisting of;
- 301 VCO x3
- 303 VCF & VCA
- 315 Dual Analog Multiplier
- 316 Random Voltage Generator
- 308 Dual DADSR
- 311 Power Supply
Live concert pictures show the VCO, VCA and DASDR patched but the 315 and 316 not used. Klaus clearly choosing more traditional analog sounds rather than using the more experimental noise and ring mod sounds available. The dual sequencer setup was used across the whole Moog and PPG system, giving Klaus a total of four 8 – 24 step sequencers.
Recreation By mid 2021 I had successfully replicated the Big Moog using Behringer and AMSynths modules, and recreated the EMS 8 Octave Filter Bank. I began to research whether the PPG 300 modules could be replicated. There are no official schematics and any available are partial and hand drawn, unfortunately Wolfgang destroyed his hardware archives around 1999.
My recreation process is therefore based on tracing out the schematics from pictures of the PCB’s and making some assumptions on components that were used and available in 1976. Here is a full list of the PPG 300 modules:
- 301 – “heated” 3046 based VCO with 4 wave shapes, PWM and Sync.
- 303 – copy of the Minimoog VCF with the addition of a 3080 based VCA.
- 304 – Noise & LFO
- 305 – Triple LFO
- 307 – Dual ADSR that uses two 555 chips.
- 308 – Dual ADSR with Delay
- 309 – Signal Mixer with 4 inputs
- 310 – Random Voltage Generator
- 311 – Power Supply with front panel
- 313 – clever analog switch, each step can be active for 1, 2, 3, 4 or 8 clock periods, before moving onto the next step
- 314 – advanced 3×8 step analog sequencer with accurate timing subdivisions.
- 315 – Dual Analog Multiplier, 4 and 2 quadrant multipliers based on 3080 OTA chips
- 316 – traditional transistor noise source and S&H (probably 555 based).
- 317 – Two 303 filters combined into a multi mode filter.
2024 Update The project to recreate these modules was paused in 2022, after releasing an 8HP 303 VCF only module and prototyping the 313, 314 and 317. I returned to the project in the Autumn of 2024 with the advantage of SMD assembly and the choice of two panel manufacturers. The initial priority is to complete the 314 sequencer using a powder coated panel and white silk screen. Whilst the PPG 300 series look like they follow Moog designs, with bare aluminium edges and lettering, this approach is too expensive for the 314 at £100 per panel.
The plan for 2025 is to recreate the Schulze system with 2x 301 VCO, 303 VCF, 308 Dual ADSR and 315 Dual Analog Multiplier, with a 317 MultiMode filter taking the place of the 311 power supply. This setup, along with 313/314 focuses on the more interesting modules, which is potentially more commercially attractive. The synth modules are 14HP wide, enabling 6 modules in a standard 84HP Eurorack case.
The synth modules will use Moog style black and silver panels, whilst the 313/314 combination will use black powder coated panels with a white silk screen. Low cost Moog style 15mm control knobs will be used throughout which keeps the cost of modules down.
Release Plan The 313/314 will be available in early 2025, with the Schulze System available later in the year as a set of 6 modules.